Help about El Cheapo PICmicro Programmer

[Jack// ani]

Hi all,

I'm using El Cheapo PICmicro Programmer by Mike Predko's for learning
uC. I don't know whether the software work in WindowsXP or not?? But
while programming I get error: Programming Failure at Address 0x00,
0x02805 was written, but 0x03fff was Read Back. And when I try to
verify I get, PICmicro MCU does not have Correct Instruction at Address
0x00, 0x02805 was expected, but 0x03fff is the actual. What could be
the problem? Is this hardware problem or operating system problem?
Any help is highly appreciated.

Thanks a lot.

 

[Jack// ani]

Hi Mark,

Thanks for reply. I'm a newbie I don't know what do you mean by
bootloader? Please tell me what it is? Please see the schematic here
http://www.myke.com/elcheapo.htm, it is having no pullup resistor, so
do I really need it, as you said? There is one more doubt regarding the
schematic, I hope you will clarify it, is pin9 and pin10 of 74LS05
connected to the same pullup resistor(R7) or not?

Thanks again.

 

[Mark Jones]

Jack// ani wrote:

Hi Mark,

Thanks for reply. I'm a newbie I don't know what do you mean by
bootloader? Please tell me what it is? Please see the schematic here
http://www.myke.com/elcheapo.htm, it is having no pullup resistor, so
do I really need it, as you said? There is one more doubt regarding the
schematic, I hope you will clarify it, is pin9 and pin10 of 74LS05
connected to the same pullup resistor(R7) or not?

Thanks again.

Aah okay. A bootloader is a program that is programmed onto a PIC so that it
can be re-programmed (arguably) much easier, using a different method and
without the need for +13v. Myke's schematic is for a regular programmer, which
is what you need.

Indeed, that schematic does not show a pullup resistor on MCLR. Let me explain
what MCLR is used for. When this pin is at +5v, the PIC operates normally. When
it is at 0v, this resets the PIC. When it is at +13v, the PIC goes into
programming mode. But in this design there is no pullup resistor. It should work
[here] just fine without it, but if you have problems try putting a 33k pullup
from MCLR to what is labeled as Vcc (+5v.)

As for operating the PIC after it is programmed, obviously for it to work in
your target circuit the MCLR pin has to have the 33k pullup to +5v. Connecting a
pushbutton switch from MCLR to GND makes a nice reset button. I recommend a
0.01uF cap across the switch also, to help smooth out any voltage spikes.

Good Luck.