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Help about El Cheapo PICmicro Programmer

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.

Reply to
Jack// ani
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Hi Jack. Does this require your chip to have a bootloader already downloaded onto it?

"3FFF" is equivalent to "not programmed" so what it's saying is, if the chip is supposed to have data there, it is either blank or not being programmed.

Make sure the PIC's MCLR pin is being driven to +13v during the programming cycle. Also MCLR should have a 33k pullup resistor to Vcc. Hope that helps.

-- "We cannot expect to stumble into happiness; it must come from within." MCJ

20050119
Reply to
Mark Jones

is

Ooops, by Vcc I meant Vdd. Connect MCLR --> 33k --> +5v, not +13.

Reply to
Mark Jones

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

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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.

Reply to
Jack// ani

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.

Reply to
Mark Jones

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