Luke Briner
Guest
Mon Mar 06, 2006 6:24 pm
I wanted to write some software to output DMX512 (a lighting protocol) to an
RS485 PC card but have problems because of the protocol. It requires 1) a
constant data stream and 2) quite precise timings. I cannot get the timing
resolution required in software because the PC clock heartbeat is too slow.
How do people build serial controllers with precise timing and automatic
data streaming? Are these something that could be controlled on a PC in
software?
TIA
Luke
CWatters
Guest
Mon Mar 06, 2006 6:48 pm
"Luke Briner" <luke_at_lbriXSner.XSplus.com> wrote in message
news:440c7e5d$0$9270$ed2619ec_at_ptn-nntp-reader01.plus.net...
Quote:
I wanted to write some software to output DMX512 (a lighting protocol) to
an
RS485 PC card but have problems because of the protocol. It requires 1) a
constant data stream and 2) quite precise timings. I cannot get the timing
resolution required in software because the PC clock heartbeat is too
slow.
A PC running an operating system like Windows does not make a good real-time
platform. If you have to use Windows the answer might be to use a single
chip micro hanging off a port to do the real time stuff. eg have the PC send
the data to the micro at it's leisure - then have the micro send it out with
the accurate timings needed.
Luke Briner
Guest
Mon Mar 06, 2006 7:02 pm
"CWatters" <colin.watters_at_pandoraBOX.be> wrote in message
news:5u%Of.298752$IT2.9381979_at_phobos.telenet-ops.be...
Quote:
A PC running an operating system like Windows does not make a good
real-time
platform. If you have to use Windows the answer might be to use a single
chip micro hanging off a port to do the real time stuff. eg have the PC
send
the data to the micro at it's leisure - then have the micro send it out
with
the accurate timings needed.
Do you mean a single board computer with, say an 68000 processor? Would I
then need to write the program in basic and upload it? The only embedded
programming I have done was at university but it was not real-time and so
I'm not sure how to program the timing required of the port.
Thanks
Luke
Jasen Betts
Guest
Tue Mar 07, 2006 7:19 am
On 2006-03-06, Luke Briner <luke_at_lbriXSner.XSplus.com> wrote:
Quote:
I wanted to write some software to output DMX512 (a lighting protocol) to an
RS485 PC card but have problems because of the protocol. It requires 1) a
constant data stream and 2) quite precise timings. I cannot get the timing
resolution required in software because the PC clock heartbeat is too slow.
How do people build serial controllers with precise timing and automatic
data streaming? Are these something that could be controlled on a PC in
software?
they use a UART with an apropriate clock rate...
Bye.
Jasen
CWatters
Guest
Tue Mar 07, 2006 9:34 am
"Luke Briner" <luke_at_lbriXSner.XSplus.com> wrote in message
news:440c875e$0$9274$ed2619ec_at_ptn-nntp-reader01.plus.net...
Quote:
Do you mean a single board computer with, say an 68000 processor? Would I
then need to write the program in basic and upload it? The only embedded
programming I have done was at university but it was not real-time and so
I'm not sure how to program the timing required of the port.
On further investigation it looks like this has all been done before.....
Here is some software for the PC...
http://users.pandora.be/freestylerdmx/begin.htm
it says it works with various DMX512 "Dongles" that hang off the printer
port. Google found
http://users.skynet.be/kristofnys/
see also
http://www.google.com/search?hl=en&q=DMX512+dongle
Tomi Holger Engdahl
Guest
Tue Mar 07, 2006 12:16 pm
"CWatters" <colin.watters_at_pandoraBOX.be> writes:
Quote:
"Luke Briner" <luke_at_lbriXSner.XSplus.com> wrote in message
news:440c875e$0$9274$ed2619ec_at_ptn-nntp-reader01.plus.net...
Do you mean a single board computer with, say an 68000 processor? Would I
then need to write the program in basic and upload it? The only embedded
programming I have done was at university but it was not real-time and so
I'm not sure how to program the timing required of the port.
On further investigation it looks like this has all been done before.....
Here is some software for the PC...
http://users.pandora.be/freestylerdmx/begin.htm
A working software.
Another software I can recommend is DMXControl from
http://www.dmxcontrol.de/
Quote:
I have built this and used that.
This works well with DMXControl.
Quote:
More links to DMX-512 circuits and software can be found here:
http://www.epanorama.net/links/lights.html#dmx512
--
Tomi Engdahl (http://www.iki.fi/then/)
Take a look at my electronics web links and documents at
http://www.epanorama.net/
SpringDiver
Guest
Tue Mar 07, 2006 2:28 pm
Personally, I'd use a PIC, Atmel being my favorite, to manage this
rather simple protocol.
The administration software would be implemented in a PC. Interface
this to your favorite USB or RS232 protocol. Have the PIC encapsulated
and manage the DMX512 data stream.
Wayne
On Mon, 6 Mar 2006 18:24:30 -0000, "Luke Briner"
<luke_at_lbriXSner.XSplus.com> wrote:
Quote:
I wanted to write some software to output DMX512 (a lighting protocol) to an
RS485 PC card but have problems because of the protocol. It requires 1) a
constant data stream and 2) quite precise timings. I cannot get the timing
resolution required in software because the PC clock heartbeat is too slow.
How do people build serial controllers with precise timing and automatic
data streaming? Are these something that could be controlled on a PC in
software?
TIA
Luke
