I have a question about the programmer and also wonder if any of the more experienced users can give a guess at what the problem is.
My old (and formerly) trusty AVR ISP, the one that uses RS-232 and has an AT90S8535 inside, finally went toes up. I have all the parts necessary to make a new one, except the AT90S8535 is a DIP, not surface mount, and I am not sure of what code I should use to flash it.
I built a circuit according to that shown in Atmel's schematic of the ISP. Unfortunately, I could not find a hex file that I could identify as ISP code for the '8535. I have a very strong suspicion that the code is the same as that in the '8535 in the STK-500. If have a version of the STK-500 firmware that Colin O'Flynn posted a long time ago and it is identical to the code that I dumped from my working STK-500, so I am confident that I have good copies of the STK-500 code.
I have wired and checked out the board, and buzzed out all the connections, checked all the voltages against what I would expect. I flipped on the power on a target board and although something is happening, its doesn't look like an AVRISP. Both LEDs are on dimly, blinking for milliseconds at a time, at about 200 Hz. Code is clearly running because when I ground one of the pins that's pulled up (PD6) it waits until I let the pin go high again.
It is not recognized by the programming software in AVR Studio 4, even though the identical firmware in the STK-500 board is recognized.
I have checked and re-checked every aspect of the circuit that I can. The only fuse I could find on the AT90S8535 is the ISP enable fuse, and of course the ISP is working.
Here are my questions:
1) Does anybody who reads this have a good enough memory to know whether AVR ISP uses the same firmware as the STK-500?
2) From my description, both red and green LEDs blinking at about 200 Hz with a low duty cycle, does this symptom suggest to anybody what is missing?
For those who would ask "Why not go to Digikey and just get a new programmer?" -Its because Digikey is 8,000 miles away and I don't want to wait weeks to continue with my current project.
I want to copy the old ISP functionality so that I can continue to use programming software in AVR STudio 4 IDE.
Thank you in advance for any constructive advice.