AVR-Chat

Similar problem I had found with the ISP wrt to the STK500 & STK501 (atmega128 adapter), was that when you have the RXD0/TXD0 from porte of the 128 on the stk501 jumpered to the spare MAX3232 and a RS232 cable plugged in the stk501 adapter pcb to a terminal, the ISP fails… and chip signatures read 0’s…

Disconnect/unjumper the 3nd serial port (“RS232 SPARE #2”) whilst using the ISP and all is ok.

/~Darren

I had a problem last week with ISP programming, or so I thought. It turned out that I had a ground problem that wiped out some Mega16s. The signature was reported as being incorrect for the blown chips, generally all 0s. Some of those that I could not program with the ISP turned out to be okay when I plugged them into the STK500 then erased/programmed them in parallel mode. You might try that.

Those that would not program with the ISP, but would after parallel erase then program, had a strange signature but not 0s.


REB


John Samperi wrote:
At 02:05 PM 3/06/2005, you wrote:

All the others report the incorrect chip signature (it changes). The chip 

that I can program reports the correct signature.

I am really lost, not sure what to try!

I don't have a STK500 so I can't be sure of the following.

However I have an AVRISP which I believe is similar and

you may want to check your programmer's clock speed. Keep it

at about 230KHz as it can only be a maximum of 1/4 the

chip's clock frequency. As the chip usual come with the

internal 1MHz clock enabled, the programmer will play up

if it is set too high, say 500KHZ or 930KHz.

Regards

John Samperi