elektroda.net NewsGroups Forum Index - Electronics Design - Replace MAX232CPE With FTD chip
Anti-Spam
Guest
Guest
Thu Sep 02, 2010 8:30 pm
Probably been covered a thousand times in this forum, but have been
doing other things for quite a few years now. I designed many years
ago some Serial interface boards using the MAX232CPE RS232 chip. I
have been asked by the owners of the product to change these to USB
connectivety. The FTD chips obviousley come to mind for such a task,
but need some help please. We would like to replace the RS232 port
with a USB port. What I would ideally like to do, is remove the MAX
chip altogether and replace it with a FTD chip. The problem for me is
that I did not write the Firmware for this project, so I am not in a
position to change anything as far as the Microcontroller Programming
is concerned (we do not have the source code). We use on the MAX chip
Tx, Rx and the CTS, RTS lines.
What we would like to achieve is for the end customer for the
interface board, to be able to load the FTD drivers, connect using the
USB port, and use the board like nothing had changed. Is this
possible? any pointers please?
PS I did ask FTD, but they just sent a data sheet with a few different
chips on, that I did not understand.
Mark in Spain.
Anti-Spam
Guest
Guest
Thu Sep 02, 2010 8:54 pm
On Thu, 2 Sep 2010 12:43:21 -0700 (PDT), "langwadt_at_fonz.dk"
<langwadt_at_fonz.dk> wrote:
Quote:
On 2 Sep., 21:30, Anti-Spam <A...@Spam.com> wrote:
Probably been covered a thousand times in this forum, but have been
doing other things for quite a few years now. I designed many years
ago some Serial interface boards using the MAX232CPE RS232 chip. I
have been asked by the owners of the product to change these to USB
connectivety. The FTD chips obviousley come to mind for such a task,
but need some help please. We would like to replace the RS232 port
with a USB port. What I would ideally like to do, is remove the MAX
chip altogether and replace it with a FTD chip. The problem for me is
that I did not write the Firmware for this project, so I am not in a
position to change anything as far as the Microcontroller Programming
is concerned (we do not have the source code). We use on the MAX chip
Tx, Rx and the CTS, RTS lines.
What we would like to achieve is for the end customer for the
interface board, to be able to load the FTD drivers, connect using the
USB port, and use the board like nothing had changed. Is this
possible? any pointers please?
that is kinda the point of using an ftdi chip, just skip the max232
and connect the
ftdi chip instead.
only difference should be that because of the way usb work the timing
might be slightly different.
it would be very easy to test, just buy an ftdi based rs232-usb
converter and use that instead of a "real" serial port, might even
consider that instead of doing a redesign
PS I did ask FTD, but they just sent a data sheet with a few different
chips on, that I did not understand.
Mark in Spain.
hmm.. might want to stick to buying a finished converter then .....
-Lasse
Probably been covered a thousand times in this forum, but have been
doing other things for quite a few years now. I designed many years
ago some Serial interface boards using the MAX232CPE RS232 chip. I
have been asked by the owners of the product to change these to USB
connectivety. The FTD chips obviousley come to mind for such a task,
but need some help please. We would like to replace the RS232 port
with a USB port. What I would ideally like to do, is remove the MAX
chip altogether and replace it with a FTD chip. The problem for me is
that I did not write the Firmware for this project, so I am not in a
position to change anything as far as the Microcontroller Programming
is concerned (we do not have the source code). We use on the MAX chip
Tx, Rx and the CTS, RTS lines.
What we would like to achieve is for the end customer for the
interface board, to be able to load the FTD drivers, connect using the
USB port, and use the board like nothing had changed. Is this
possible? any pointers please?
that is kinda the point of using an ftdi chip, just skip the max232
and connect the
ftdi chip instead.
only difference should be that because of the way usb work the timing
might be slightly different.
it would be very easy to test, just buy an ftdi based rs232-usb
converter and use that instead of a "real" serial port, might even
consider that instead of doing a redesign
PS I did ask FTD, but they just sent a data sheet with a few different
chips on, that I did not understand.
Mark in Spain.
hmm.. might want to stick to buying a finished converter then .....
-Lasse
Blimey that was quick, thanks.
The original product, still sells and I think that the end customers
are probably doing what you suggest. It would be a less clumsy
solution though, if they could plug straight into the interface board,
the saving on the MAX chip, going some way to pay for the USB
converter,
hamilton
Guest
Guest
Thu Sep 02, 2010 8:55 pm
On 9/2/2010 1:30 PM, Anti-Spam wrote:
Quote:
Probably been covered a thousand times in this forum, but have been
doing other things for quite a few years now. I designed many years
ago some Serial interface boards using the MAX232CPE RS232 chip. I
have been asked by the owners of the product to change these to USB
connectivety. The FTD chips obviousley come to mind for such a task,
but need some help please. We would like to replace the RS232 port
with a USB port. What I would ideally like to do, is remove the MAX
chip altogether and replace it with a FTD chip. The problem for me is
that I did not write the Firmware for this project, so I am not in a
position to change anything as far as the Microcontroller Programming
is concerned (we do not have the source code). We use on the MAX chip
Tx, Rx and the CTS, RTS lines.
What we would like to achieve is for the end customer for the
interface board, to be able to load the FTD drivers, connect using the
USB port, and use the board like nothing had changed. Is this
possible? any pointers please?
PS I did ask FTD, but they just sent a data sheet with a few different
chips on, that I did not understand.
Mark in Spain.
doing other things for quite a few years now. I designed many years
ago some Serial interface boards using the MAX232CPE RS232 chip. I
have been asked by the owners of the product to change these to USB
connectivety. The FTD chips obviousley come to mind for such a task,
but need some help please. We would like to replace the RS232 port
with a USB port. What I would ideally like to do, is remove the MAX
chip altogether and replace it with a FTD chip. The problem for me is
that I did not write the Firmware for this project, so I am not in a
position to change anything as far as the Microcontroller Programming
is concerned (we do not have the source code). We use on the MAX chip
Tx, Rx and the CTS, RTS lines.
What we would like to achieve is for the end customer for the
interface board, to be able to load the FTD drivers, connect using the
USB port, and use the board like nothing had changed. Is this
possible? any pointers please?
PS I did ask FTD, but they just sent a data sheet with a few different
chips on, that I did not understand.
Mark in Spain.
Yes, this has been done many times.
Look at someone's project and just copy it.
http://www.sparkfun.com/commerce/product_info.php?products_id=9115
Its FTDIs design and code, so copy to your hearts content.
h
Jim Thompson
Guest
Guest
Thu Sep 02, 2010 8:55 pm
On Thu, 02 Sep 2010 21:30:57 +0200, Anti-Spam <Anti_at_Spam.com> wrote:
Quote:
Probably been covered a thousand times in this forum, but have been
doing other things for quite a few years now. I designed many years
ago some Serial interface boards using the MAX232CPE RS232 chip. I
have been asked by the owners of the product to change these to USB
connectivety. The FTD chips obviousley come to mind for such a task,
but need some help please. We would like to replace the RS232 port
with a USB port. What I would ideally like to do, is remove the MAX
chip altogether and replace it with a FTD chip. The problem for me is
that I did not write the Firmware for this project, so I am not in a
position to change anything as far as the Microcontroller Programming
is concerned (we do not have the source code). We use on the MAX chip
Tx, Rx and the CTS, RTS lines.
What we would like to achieve is for the end customer for the
interface board, to be able to load the FTD drivers, connect using the
USB port, and use the board like nothing had changed. Is this
possible? any pointers please?
PS I did ask FTD, but they just sent a data sheet with a few different
chips on, that I did not understand.
Mark in Spain.
doing other things for quite a few years now. I designed many years
ago some Serial interface boards using the MAX232CPE RS232 chip. I
have been asked by the owners of the product to change these to USB
connectivety. The FTD chips obviousley come to mind for such a task,
but need some help please. We would like to replace the RS232 port
with a USB port. What I would ideally like to do, is remove the MAX
chip altogether and replace it with a FTD chip. The problem for me is
that I did not write the Firmware for this project, so I am not in a
position to change anything as far as the Microcontroller Programming
is concerned (we do not have the source code). We use on the MAX chip
Tx, Rx and the CTS, RTS lines.
What we would like to achieve is for the end customer for the
interface board, to be able to load the FTD drivers, connect using the
USB port, and use the board like nothing had changed. Is this
possible? any pointers please?
PS I did ask FTD, but they just sent a data sheet with a few different
chips on, that I did not understand.
Mark in Spain.
Maybe like this...
http://www.google.com/imgres?imgurl=http://makecircuits.com/blog/wp-content/uploads/2008/12/rs232-serial-to-usb-converter-cable-schematic.gif&imgrefurl=http://makecircuits.com/blog/2008-12-25-rs232-to-usb-converter.html&h=641&w=694&sz=22&tbnid=G_FwwXHShiWdxM:&tbnh=128&tbnw=139&prev=/images%3Fq%3D%2522RS232%2Bto%2BUSB%2522&zoom=1&q=%22RS232+to+USB%22&hl=en&usg=__cwXc5KKbkszWyY0GfC1q7fvTa1s=&sa=X&ei=fQCATLHKLoa-sAPXnfj1Cg&ved=0CDUQ9QEwAw
It's a lengthy URL, so beware if it wraps in your reader.
...Jim Thompson
--
| James E.Thompson, CTO | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |
Democrats are best served up prepared as a hash
Otherwise my dogs will refuse to eat them
Rich Webb
Guest
Guest
Thu Sep 02, 2010 9:25 pm
On Thu, 02 Sep 2010 21:30:57 +0200, Anti-Spam <Anti_at_Spam.com> wrote:
Quote:
Probably been covered a thousand times in this forum, but have been
doing other things for quite a few years now. I designed many years
ago some Serial interface boards using the MAX232CPE RS232 chip. I
have been asked by the owners of the product to change these to USB
connectivety. The FTD chips obviousley come to mind for such a task,
but need some help please. We would like to replace the RS232 port
with a USB port. What I would ideally like to do, is remove the MAX
chip altogether and replace it with a FTD chip. The problem for me is
that I did not write the Firmware for this project, so I am not in a
position to change anything as far as the Microcontroller Programming
is concerned (we do not have the source code). We use on the MAX chip
Tx, Rx and the CTS, RTS lines.
What we would like to achieve is for the end customer for the
interface board, to be able to load the FTD drivers, connect using the
USB port, and use the board like nothing had changed. Is this
possible?
doing other things for quite a few years now. I designed many years
ago some Serial interface boards using the MAX232CPE RS232 chip. I
have been asked by the owners of the product to change these to USB
connectivety. The FTD chips obviousley come to mind for such a task,
but need some help please. We would like to replace the RS232 port
with a USB port. What I would ideally like to do, is remove the MAX
chip altogether and replace it with a FTD chip. The problem for me is
that I did not write the Firmware for this project, so I am not in a
position to change anything as far as the Microcontroller Programming
is concerned (we do not have the source code). We use on the MAX chip
Tx, Rx and the CTS, RTS lines.
What we would like to achieve is for the end customer for the
interface board, to be able to load the FTD drivers, connect using the
USB port, and use the board like nothing had changed. Is this
possible?
Yes, it is. It's also possible that it won't work at all.
If the RTS/CTS lines are used "as intended," that is, for serial flow
control, then the probability that it will work correctly and
transparently is very high, approaching 1.
If, however, the RTS/CTS pair are used as a "side channel" for signaling
and if the signals are required to be synchronized with the serial data
stream or with each other, then you may have a problem.
One other possible problem is that some applications limit the number of
COM ports that they can "see." For example, the FlukeView software for
their ScopeMeters will only connect up through COM8. USB serial ports,
on the other hand, can be up in much higher-numbered ports depending on
how many different USB-serial gadgets a given machine has used in the
past.
It is possible to work around this, if necessary, by going into the
Windows Device Manager and manually assigning a "visible" COM port
number to a particular USB-serial instance. In this case, the change
from a hardware RS-232 port to a virtual USB-serial port would work
(subject to the RTS/CTS caveats above) but could require the end user to
take an extra step or two to set it up.
--
Rich Webb Norfolk, VA
Anti-Spam
Guest
Guest
Thu Sep 02, 2010 9:51 pm
On Thu, 02 Sep 2010 16:25:16 -0400, Rich Webb
<bbew.ar_at_mapson.nozirev.ten> wrote:
Quote:
On Thu, 02 Sep 2010 21:30:57 +0200, Anti-Spam <Anti_at_Spam.com> wrote:
Probably been covered a thousand times in this forum, but have been
doing other things for quite a few years now. I designed many years
ago some Serial interface boards using the MAX232CPE RS232 chip. I
have been asked by the owners of the product to change these to USB
connectivety. The FTD chips obviousley come to mind for such a task,
but need some help please. We would like to replace the RS232 port
with a USB port. What I would ideally like to do, is remove the MAX
chip altogether and replace it with a FTD chip. The problem for me is
that I did not write the Firmware for this project, so I am not in a
position to change anything as far as the Microcontroller Programming
is concerned (we do not have the source code). We use on the MAX chip
Tx, Rx and the CTS, RTS lines.
What we would like to achieve is for the end customer for the
interface board, to be able to load the FTD drivers, connect using the
USB port, and use the board like nothing had changed. Is this
possible?
Yes, it is. It's also possible that it won't work at all.
If the RTS/CTS lines are used "as intended," that is, for serial flow
control, then the probability that it will work correctly and
transparently is very high, approaching 1.
If, however, the RTS/CTS pair are used as a "side channel" for signaling
and if the signals are required to be synchronized with the serial data
stream or with each other, then you may have a problem.
One other possible problem is that some applications limit the number of
COM ports that they can "see." For example, the FlukeView software for
their ScopeMeters will only connect up through COM8. USB serial ports,
on the other hand, can be up in much higher-numbered ports depending on
how many different USB-serial gadgets a given machine has used in the
past.
It is possible to work around this, if necessary, by going into the
Windows Device Manager and manually assigning a "visible" COM port
number to a particular USB-serial instance. In this case, the change
from a hardware RS-232 port to a virtual USB-serial port would work
(subject to the RTS/CTS caveats above) but could require the end user to
take an extra step or two to set it up.
Probably been covered a thousand times in this forum, but have been
doing other things for quite a few years now. I designed many years
ago some Serial interface boards using the MAX232CPE RS232 chip. I
have been asked by the owners of the product to change these to USB
connectivety. The FTD chips obviousley come to mind for such a task,
but need some help please. We would like to replace the RS232 port
with a USB port. What I would ideally like to do, is remove the MAX
chip altogether and replace it with a FTD chip. The problem for me is
that I did not write the Firmware for this project, so I am not in a
position to change anything as far as the Microcontroller Programming
is concerned (we do not have the source code). We use on the MAX chip
Tx, Rx and the CTS, RTS lines.
What we would like to achieve is for the end customer for the
interface board, to be able to load the FTD drivers, connect using the
USB port, and use the board like nothing had changed. Is this
possible?
Yes, it is. It's also possible that it won't work at all.
If the RTS/CTS lines are used "as intended," that is, for serial flow
control, then the probability that it will work correctly and
transparently is very high, approaching 1.
If, however, the RTS/CTS pair are used as a "side channel" for signaling
and if the signals are required to be synchronized with the serial data
stream or with each other, then you may have a problem.
One other possible problem is that some applications limit the number of
COM ports that they can "see." For example, the FlukeView software for
their ScopeMeters will only connect up through COM8. USB serial ports,
on the other hand, can be up in much higher-numbered ports depending on
how many different USB-serial gadgets a given machine has used in the
past.
It is possible to work around this, if necessary, by going into the
Windows Device Manager and manually assigning a "visible" COM port
number to a particular USB-serial instance. In this case, the change
from a hardware RS-232 port to a virtual USB-serial port would work
(subject to the RTS/CTS caveats above) but could require the end user to
take an extra step or two to set it up.
The guy who wrote the Firmware for this project was an older, very
serious Polish guy, so the CTS and RTS implimentation was more than
probably, text book RS232 implimentation.
Nico Coesel
Guest
Guest
Thu Sep 02, 2010 10:01 pm
Anti-Spam <Anti_at_Spam.com> wrote:
Quote:
Probably been covered a thousand times in this forum, but have been
doing other things for quite a few years now. I designed many years
ago some Serial interface boards using the MAX232CPE RS232 chip. I
have been asked by the owners of the product to change these to USB
connectivety. The FTD chips obviousley come to mind for such a task,
but need some help please. We would like to replace the RS232 port
with a USB port. What I would ideally like to do, is remove the MAX
chip altogether and replace it with a FTD chip. The problem for me is
that I did not write the Firmware for this project, so I am not in a
position to change anything as far as the Microcontroller Programming
is concerned (we do not have the source code). We use on the MAX chip
Tx, Rx and the CTS, RTS lines.
What we would like to achieve is for the end customer for the
interface board, to be able to load the FTD drivers, connect using the
USB port, and use the board like nothing had changed. Is this
possible? any pointers please?
doing other things for quite a few years now. I designed many years
ago some Serial interface boards using the MAX232CPE RS232 chip. I
have been asked by the owners of the product to change these to USB
connectivety. The FTD chips obviousley come to mind for such a task,
but need some help please. We would like to replace the RS232 port
with a USB port. What I would ideally like to do, is remove the MAX
chip altogether and replace it with a FTD chip. The problem for me is
that I did not write the Firmware for this project, so I am not in a
position to change anything as far as the Microcontroller Programming
is concerned (we do not have the source code). We use on the MAX chip
Tx, Rx and the CTS, RTS lines.
What we would like to achieve is for the end customer for the
interface board, to be able to load the FTD drivers, connect using the
USB port, and use the board like nothing had changed. Is this
possible? any pointers please?
No problem at all. There are many chips like these. I often use the
CP210x series from Silabs.
--
Failure does not prove something is impossible, failure simply
indicates you are not using the right tools...
nico_at_nctdevpuntnl (punt=.)
--------------------------------------------------------------
Joel Koltner
Guest
Guest
Thu Sep 02, 2010 10:06 pm
"Anti-Spam" <Anti_at_Spam.com> wrote in message
news:pd3086dp85j70uodfup6k0vughjuol7joj_at_4ax.com...
Quote:
The guy who wrote the Firmware for this project was an older, very
serious Polish guy, so the CTS and RTS implimentation was more than
probably, text book RS232 implimentation.
serious Polish guy, so the CTS and RTS implimentation was more than
probably, text book RS232 implimentation.
In all likelihood, you'll be fine then -- just use an FT232R in place of your
Max232 chip. If you don't bother changing the content of the FT232R's EEPROM,
it'll just show up as a "generic serial port" (and Windows will dutifully
assign a COM port to it) -- this is probably what you want, although if feel
like it you can use FTDI's (free) FT_PROG program to change the FT232R's
EEPROM so as to provide a custom description for your board or even use a
non-standard product ID code so that it's easier to "find" from your PC-side
application (...but leveraging this requires changing the PC-side software, of
course).
If you want to test out the idea before comitting to a board spin, just buy an
off-the-shelf USB to serial port converter cable that advertises itself as
using the FTDI chips and heck things up a bit.
---Joel
Dave Platt
Guest
Guest
Thu Sep 02, 2010 10:14 pm
In article <81uv76depol85peptunrg4lh60vc4o3gkp_at_4ax.com>,
Anti-Spam <Anti_at_Spam.com> wrote:
Quote:
Probably been covered a thousand times in this forum, but have been
doing other things for quite a few years now. I designed many years
ago some Serial interface boards using the MAX232CPE RS232 chip. I
have been asked by the owners of the product to change these to USB
connectivety. The FTD chips obviousley come to mind for such a task,
but need some help please. We would like to replace the RS232 port
with a USB port. What I would ideally like to do, is remove the MAX
chip altogether and replace it with a FTD chip. The problem for me is
that I did not write the Firmware for this project, so I am not in a
position to change anything as far as the Microcontroller Programming
is concerned (we do not have the source code). We use on the MAX chip
Tx, Rx and the CTS, RTS lines.
What we would like to achieve is for the end customer for the
interface board, to be able to load the FTD drivers, connect using the
USB port, and use the board like nothing had changed. Is this
possible? any pointers please?
doing other things for quite a few years now. I designed many years
ago some Serial interface boards using the MAX232CPE RS232 chip. I
have been asked by the owners of the product to change these to USB
connectivety. The FTD chips obviousley come to mind for such a task,
but need some help please. We would like to replace the RS232 port
with a USB port. What I would ideally like to do, is remove the MAX
chip altogether and replace it with a FTD chip. The problem for me is
that I did not write the Firmware for this project, so I am not in a
position to change anything as far as the Microcontroller Programming
is concerned (we do not have the source code). We use on the MAX chip
Tx, Rx and the CTS, RTS lines.
What we would like to achieve is for the end customer for the
interface board, to be able to load the FTD drivers, connect using the
USB port, and use the board like nothing had changed. Is this
possible? any pointers please?
I'm assuming that your board is, in effect, the "target" of the USB
connection. That is to say:
- Currently, it has a serial port on it. This has a MAX232CPE chip,
sitting between your system's onboard microcontroller and the
serial-port connector (DB-9). The onboard microcontroller has TX
and RX line (and perhaps flow-control as well), operated with
standard TTL/CMOS voltages and conventions, that are wired to the
MAX232CPE. The MAX232CPE is converting these CMOS-level signals to
standard RS-232 voltages and polarities, and feeding them to the
DB-9 connector.
If that's the case, you've got a pretty easy solution with the FTDI
chips. Your on-board micro will not require any firmeware changes at
all... in fact it won't realize that anything has changed.
All you need to do is replace the DB-9 and the MAX232CPU, with one of
the FTDI chips and a USB jack (and you can buy modules which have both
of these in a single unit). Simply connect TX, RX, and the
flow-control signals from your on-board micro to the corresponding
pins on the FTDI chip or module.
Your users will then need to install the FTDI USB driver on their PC
(it's available as a built-in module on Linux, by the way). Once they
plug in the cable to the FTDI, their system will recognize the chip
and create a "virtual serial port" that the user's communication
software can connect to. They'll need to set the baud rate, data
encoding, flow control, etc. for this, just as they would already be
doing for the "real" serial port.
--
Dave Platt <dplatt_at_radagast.org> AE6EO
Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!
langwadt@fonz.dk
Guest
Guest
Thu Sep 02, 2010 10:43 pm
On 2 Sep., 21:30, Anti-Spam <A...@Spam.com> wrote:
Quote:
Probably been covered a thousand times in this forum, but have been
doing other things for quite a few years now. I designed many years
ago some Serial interface boards using the MAX232CPE RS232 chip. I
have been asked by the owners of the product to change these to USB
connectivety. The FTD chips obviousley come to mind for such a task,
but need some help please. We would like to replace the RS232 port
with a USB port. What I would ideally like to do, is remove the MAX
chip altogether and replace it with a FTD chip. The problem for me is
that I did not write the Firmware for this project, so I am not in a
position to change anything as far as the Microcontroller Programming
is concerned (we do not have the source code). We use on the MAX chip
Tx, Rx and the CTS, RTS lines.
What we would like to achieve is for the end customer for the
interface board, to be able to load the FTD drivers, connect using the
USB port, and use the board like nothing had changed. Is this
possible? any pointers please?
doing other things for quite a few years now. I designed many years
ago some Serial interface boards using the MAX232CPE RS232 chip. I
have been asked by the owners of the product to change these to USB
connectivety. The FTD chips obviousley come to mind for such a task,
but need some help please. We would like to replace the RS232 port
with a USB port. What I would ideally like to do, is remove the MAX
chip altogether and replace it with a FTD chip. The problem for me is
that I did not write the Firmware for this project, so I am not in a
position to change anything as far as the Microcontroller Programming
is concerned (we do not have the source code). We use on the MAX chip
Tx, Rx and the CTS, RTS lines.
What we would like to achieve is for the end customer for the
interface board, to be able to load the FTD drivers, connect using the
USB port, and use the board like nothing had changed. Is this
possible? any pointers please?
that is kinda the point of using an ftdi chip, just skip the max232
and connect the
ftdi chip instead.
only difference should be that because of the way usb work the timing
might be slightly different.
it would be very easy to test, just buy an ftdi based rs232-usb
converter and use that instead of a "real" serial port, might even
consider that instead of doing a redesign
Quote:
PS I did ask FTD, but they just sent a data sheet with a few different
chips on, that I did not understand.
Mark in Spain.
chips on, that I did not understand.
Mark in Spain.
hmm.. might want to stick to buying a finished converter then .....
-Lasse
TTman
Guest
Guest
Thu Sep 02, 2010 10:43 pm
SNIP
Quote:
Your users will then need to install the FTDI USB driver on their PC
(it's available as a built-in module on Linux, by the way). Once they
plug in the cable to the FTDI, their system will recognize the chip
and create a "virtual serial port" that the user's communication
software can connect to. They'll need to set the baud rate, data
encoding, flow control, etc. for this, just as they would already be
doing for the "real" serial port.
--
That's all well and good so long as the application software doesn't
read/write directly to the legacy (ISA) com port addresses....
hamilton
Guest
Guest
Thu Sep 02, 2010 11:26 pm
On 9/2/2010 2:51 PM, Anti-Spam wrote:
Quote:
On Thu, 02 Sep 2010 16:25:16 -0400, Rich Webb
bbew.ar_at_mapson.nozirev.ten> wrote:
On Thu, 02 Sep 2010 21:30:57 +0200, Anti-Spam<Anti_at_Spam.com> wrote:
Probably been covered a thousand times in this forum, but have been
doing other things for quite a few years now. I designed many years
ago some Serial interface boards using the MAX232CPE RS232 chip. I
have been asked by the owners of the product to change these to USB
connectivety. The FTD chips obviousley come to mind for such a task,
but need some help please. We would like to replace the RS232 port
with a USB port. What I would ideally like to do, is remove the MAX
chip altogether and replace it with a FTD chip. The problem for me is
that I did not write the Firmware for this project, so I am not in a
position to change anything as far as the Microcontroller Programming
is concerned (we do not have the source code). We use on the MAX chip
Tx, Rx and the CTS, RTS lines.
What we would like to achieve is for the end customer for the
interface board, to be able to load the FTD drivers, connect using the
USB port, and use the board like nothing had changed. Is this
possible?
Yes, it is. It's also possible that it won't work at all.
If the RTS/CTS lines are used "as intended," that is, for serial flow
control, then the probability that it will work correctly and
transparently is very high, approaching 1.
If, however, the RTS/CTS pair are used as a "side channel" for signaling
and if the signals are required to be synchronized with the serial data
stream or with each other, then you may have a problem.
One other possible problem is that some applications limit the number of
COM ports that they can "see." For example, the FlukeView software for
their ScopeMeters will only connect up through COM8. USB serial ports,
on the other hand, can be up in much higher-numbered ports depending on
how many different USB-serial gadgets a given machine has used in the
past.
It is possible to work around this, if necessary, by going into the
Windows Device Manager and manually assigning a "visible" COM port
number to a particular USB-serial instance. In this case, the change
from a hardware RS-232 port to a virtual USB-serial port would work
(subject to the RTS/CTS caveats above) but could require the end user to
take an extra step or two to set it up.
The guy who wrote the Firmware for this project was an older, very
serious Polish guy, so the CTS and RTS implimentation was more than
probably, text book RS232 implimentation.
bbew.ar_at_mapson.nozirev.ten> wrote:
On Thu, 02 Sep 2010 21:30:57 +0200, Anti-Spam<Anti_at_Spam.com> wrote:
Probably been covered a thousand times in this forum, but have been
doing other things for quite a few years now. I designed many years
ago some Serial interface boards using the MAX232CPE RS232 chip. I
have been asked by the owners of the product to change these to USB
connectivety. The FTD chips obviousley come to mind for such a task,
but need some help please. We would like to replace the RS232 port
with a USB port. What I would ideally like to do, is remove the MAX
chip altogether and replace it with a FTD chip. The problem for me is
that I did not write the Firmware for this project, so I am not in a
position to change anything as far as the Microcontroller Programming
is concerned (we do not have the source code). We use on the MAX chip
Tx, Rx and the CTS, RTS lines.
What we would like to achieve is for the end customer for the
interface board, to be able to load the FTD drivers, connect using the
USB port, and use the board like nothing had changed. Is this
possible?
Yes, it is. It's also possible that it won't work at all.
If the RTS/CTS lines are used "as intended," that is, for serial flow
control, then the probability that it will work correctly and
transparently is very high, approaching 1.
If, however, the RTS/CTS pair are used as a "side channel" for signaling
and if the signals are required to be synchronized with the serial data
stream or with each other, then you may have a problem.
One other possible problem is that some applications limit the number of
COM ports that they can "see." For example, the FlukeView software for
their ScopeMeters will only connect up through COM8. USB serial ports,
on the other hand, can be up in much higher-numbered ports depending on
how many different USB-serial gadgets a given machine has used in the
past.
It is possible to work around this, if necessary, by going into the
Windows Device Manager and manually assigning a "visible" COM port
number to a particular USB-serial instance. In this case, the change
from a hardware RS-232 port to a virtual USB-serial port would work
(subject to the RTS/CTS caveats above) but could require the end user to
take an extra step or two to set it up.
The guy who wrote the Firmware for this project was an older, very
serious Polish guy, so the CTS and RTS implimentation was more than
probably, text book RS232 implimentation.
The embedded side won't be a problem.
Does this board connect to a PC ??
If so, does the PC software toggle the CTS/RTS lines by writing the I/O
ports on the PC buss ??
If this is true, you will not be able to use a USB serial port.
You will need to re-write the PC software.
h
Anti-Spam
Guest
Guest
Fri Sep 03, 2010 6:19 am
On Thu, 2 Sep 2010 22:43:27 +0100, "TTman" <pcw1.cad_at_ntlworld.com>
wrote:
Quote:
SNIP
Your users will then need to install the FTDI USB driver on their PC
(it's available as a built-in module on Linux, by the way). Once they
plug in the cable to the FTDI, their system will recognize the chip
and create a "virtual serial port" that the user's communication
software can connect to. They'll need to set the baud rate, data
encoding, flow control, etc. for this, just as they would already be
doing for the "real" serial port.
--
That's all well and good so long as the application software doesn't
read/write directly to the legacy (ISA) com port addresses....
Some history, I at the time of the design, could not write firmware.
Your users will then need to install the FTDI USB driver on their PC
(it's available as a built-in module on Linux, by the way). Once they
plug in the cable to the FTDI, their system will recognize the chip
and create a "virtual serial port" that the user's communication
software can connect to. They'll need to set the baud rate, data
encoding, flow control, etc. for this, just as they would already be
doing for the "real" serial port.
--
That's all well and good so long as the application software doesn't
read/write directly to the legacy (ISA) com port addresses....
Some history, I at the time of the design, could not write firmware.
So how exactly the CTS/RTS lines on the RS232 port is being used, I am
not able to answer.
In answer to an earlier question, as far as I know, existing customers
of this interface board, are using PC based equipment.
What we would like to achieve if possible, is for existing customers
to carry on using the product without change to the software they have
had written for their host PC (just load the FTD drivers).
We also want any new potential customers, not to be put off trying the
interface, just because it does not have a USB port.
Anti-Spam
Guest
Guest
Fri Sep 03, 2010 6:24 am
On Thu, 2 Sep 2010 14:14:03 -0700, dplatt_at_radagast.org (Dave Platt)
wrote:
Quote:
In article <81uv76depol85peptunrg4lh60vc4o3gkp_at_4ax.com>,
Anti-Spam <Anti_at_Spam.com> wrote:
Probably been covered a thousand times in this forum, but have been
doing other things for quite a few years now. I designed many years
ago some Serial interface boards using the MAX232CPE RS232 chip. I
have been asked by the owners of the product to change these to USB
connectivety. The FTD chips obviousley come to mind for such a task,
but need some help please. We would like to replace the RS232 port
with a USB port. What I would ideally like to do, is remove the MAX
chip altogether and replace it with a FTD chip. The problem for me is
that I did not write the Firmware for this project, so I am not in a
position to change anything as far as the Microcontroller Programming
is concerned (we do not have the source code). We use on the MAX chip
Tx, Rx and the CTS, RTS lines.
What we would like to achieve is for the end customer for the
interface board, to be able to load the FTD drivers, connect using the
USB port, and use the board like nothing had changed. Is this
possible? any pointers please?
I'm assuming that your board is, in effect, the "target" of the USB
connection. That is to say:
- Currently, it has a serial port on it. This has a MAX232CPE chip,
sitting between your system's onboard microcontroller and the
serial-port connector (DB-9). The onboard microcontroller has TX
and RX line (and perhaps flow-control as well), operated with
standard TTL/CMOS voltages and conventions, that are wired to the
MAX232CPE. The MAX232CPE is converting these CMOS-level signals to
standard RS-232 voltages and polarities, and feeding them to the
DB-9 connector.
If that's the case, you've got a pretty easy solution with the FTDI
chips. Your on-board micro will not require any firmeware changes at
all... in fact it won't realize that anything has changed.
All you need to do is replace the DB-9 and the MAX232CPU, with one of
the FTDI chips and a USB jack (and you can buy modules which have both
of these in a single unit). Simply connect TX, RX, and the
flow-control signals from your on-board micro to the corresponding
pins on the FTDI chip or module.
Your users will then need to install the FTDI USB driver on their PC
(it's available as a built-in module on Linux, by the way). Once they
plug in the cable to the FTDI, their system will recognize the chip
and create a "virtual serial port" that the user's communication
software can connect to. They'll need to set the baud rate, data
encoding, flow control, etc. for this, just as they would already be
doing for the "real" serial port.
Anti-Spam <Anti_at_Spam.com> wrote:
Probably been covered a thousand times in this forum, but have been
doing other things for quite a few years now. I designed many years
ago some Serial interface boards using the MAX232CPE RS232 chip. I
have been asked by the owners of the product to change these to USB
connectivety. The FTD chips obviousley come to mind for such a task,
but need some help please. We would like to replace the RS232 port
with a USB port. What I would ideally like to do, is remove the MAX
chip altogether and replace it with a FTD chip. The problem for me is
that I did not write the Firmware for this project, so I am not in a
position to change anything as far as the Microcontroller Programming
is concerned (we do not have the source code). We use on the MAX chip
Tx, Rx and the CTS, RTS lines.
What we would like to achieve is for the end customer for the
interface board, to be able to load the FTD drivers, connect using the
USB port, and use the board like nothing had changed. Is this
possible? any pointers please?
I'm assuming that your board is, in effect, the "target" of the USB
connection. That is to say:
- Currently, it has a serial port on it. This has a MAX232CPE chip,
sitting between your system's onboard microcontroller and the
serial-port connector (DB-9). The onboard microcontroller has TX
and RX line (and perhaps flow-control as well), operated with
standard TTL/CMOS voltages and conventions, that are wired to the
MAX232CPE. The MAX232CPE is converting these CMOS-level signals to
standard RS-232 voltages and polarities, and feeding them to the
DB-9 connector.
If that's the case, you've got a pretty easy solution with the FTDI
chips. Your on-board micro will not require any firmeware changes at
all... in fact it won't realize that anything has changed.
All you need to do is replace the DB-9 and the MAX232CPU, with one of
the FTDI chips and a USB jack (and you can buy modules which have both
of these in a single unit). Simply connect TX, RX, and the
flow-control signals from your on-board micro to the corresponding
pins on the FTDI chip or module.
Your users will then need to install the FTDI USB driver on their PC
(it's available as a built-in module on Linux, by the way). Once they
plug in the cable to the FTDI, their system will recognize the chip
and create a "virtual serial port" that the user's communication
software can connect to. They'll need to set the baud rate, data
encoding, flow control, etc. for this, just as they would already be
doing for the "real" serial port.
Your statement at the beginig of your post is correct, and yes it does
use the CTS/RTS lines for flow control. I really need help on which
FTD chip to use, and any examples of known working circuitry, I can
copy, err sorry I meant emulate.
Anti-Spam
Guest
Guest
Fri Sep 03, 2010 6:27 am
On Thu, 02 Sep 2010 16:26:50 -0600, hamilton <hamilton_at_nothere.com>
wrote:
Quote:
On 9/2/2010 2:51 PM, Anti-Spam wrote:
On Thu, 02 Sep 2010 16:25:16 -0400, Rich Webb
bbew.ar_at_mapson.nozirev.ten> wrote:
On Thu, 02 Sep 2010 21:30:57 +0200, Anti-Spam<Anti_at_Spam.com> wrote:
Probably been covered a thousand times in this forum, but have been
doing other things for quite a few years now. I designed many years
ago some Serial interface boards using the MAX232CPE RS232 chip. I
have been asked by the owners of the product to change these to USB
connectivety. The FTD chips obviousley come to mind for such a task,
but need some help please. We would like to replace the RS232 port
with a USB port. What I would ideally like to do, is remove the MAX
chip altogether and replace it with a FTD chip. The problem for me is
that I did not write the Firmware for this project, so I am not in a
position to change anything as far as the Microcontroller Programming
is concerned (we do not have the source code). We use on the MAX chip
Tx, Rx and the CTS, RTS lines.
What we would like to achieve is for the end customer for the
interface board, to be able to load the FTD drivers, connect using the
USB port, and use the board like nothing had changed. Is this
possible?
Yes, it is. It's also possible that it won't work at all.
If the RTS/CTS lines are used "as intended," that is, for serial flow
control, then the probability that it will work correctly and
transparently is very high, approaching 1.
If, however, the RTS/CTS pair are used as a "side channel" for signaling
and if the signals are required to be synchronized with the serial data
stream or with each other, then you may have a problem.
One other possible problem is that some applications limit the number of
COM ports that they can "see." For example, the FlukeView software for
their ScopeMeters will only connect up through COM8. USB serial ports,
on the other hand, can be up in much higher-numbered ports depending on
how many different USB-serial gadgets a given machine has used in the
past.
It is possible to work around this, if necessary, by going into the
Windows Device Manager and manually assigning a "visible" COM port
number to a particular USB-serial instance. In this case, the change
from a hardware RS-232 port to a virtual USB-serial port would work
(subject to the RTS/CTS caveats above) but could require the end user to
take an extra step or two to set it up.
The guy who wrote the Firmware for this project was an older, very
serious Polish guy, so the CTS and RTS implimentation was more than
probably, text book RS232 implimentation.
The embedded side won't be a problem.
Does this board connect to a PC ??
If so, does the PC software toggle the CTS/RTS lines by writing the I/O
ports on the PC buss ??
If this is true, you will not be able to use a USB serial port.
You will need to re-write the PC software.
h
Thanks, do you have any example circuits?
On Thu, 02 Sep 2010 16:25:16 -0400, Rich Webb
bbew.ar_at_mapson.nozirev.ten> wrote:
On Thu, 02 Sep 2010 21:30:57 +0200, Anti-Spam<Anti_at_Spam.com> wrote:
Probably been covered a thousand times in this forum, but have been
doing other things for quite a few years now. I designed many years
ago some Serial interface boards using the MAX232CPE RS232 chip. I
have been asked by the owners of the product to change these to USB
connectivety. The FTD chips obviousley come to mind for such a task,
but need some help please. We would like to replace the RS232 port
with a USB port. What I would ideally like to do, is remove the MAX
chip altogether and replace it with a FTD chip. The problem for me is
that I did not write the Firmware for this project, so I am not in a
position to change anything as far as the Microcontroller Programming
is concerned (we do not have the source code). We use on the MAX chip
Tx, Rx and the CTS, RTS lines.
What we would like to achieve is for the end customer for the
interface board, to be able to load the FTD drivers, connect using the
USB port, and use the board like nothing had changed. Is this
possible?
Yes, it is. It's also possible that it won't work at all.
If the RTS/CTS lines are used "as intended," that is, for serial flow
control, then the probability that it will work correctly and
transparently is very high, approaching 1.
If, however, the RTS/CTS pair are used as a "side channel" for signaling
and if the signals are required to be synchronized with the serial data
stream or with each other, then you may have a problem.
One other possible problem is that some applications limit the number of
COM ports that they can "see." For example, the FlukeView software for
their ScopeMeters will only connect up through COM8. USB serial ports,
on the other hand, can be up in much higher-numbered ports depending on
how many different USB-serial gadgets a given machine has used in the
past.
It is possible to work around this, if necessary, by going into the
Windows Device Manager and manually assigning a "visible" COM port
number to a particular USB-serial instance. In this case, the change
from a hardware RS-232 port to a virtual USB-serial port would work
(subject to the RTS/CTS caveats above) but could require the end user to
take an extra step or two to set it up.
The guy who wrote the Firmware for this project was an older, very
serious Polish guy, so the CTS and RTS implimentation was more than
probably, text book RS232 implimentation.
The embedded side won't be a problem.
Does this board connect to a PC ??
If so, does the PC software toggle the CTS/RTS lines by writing the I/O
ports on the PC buss ??
If this is true, you will not be able to use a USB serial port.
You will need to re-write the PC software.
h
Thanks, do you have any example circuits?
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