There is a new release of AVRISP Emulation for Arduino. This is an Arduino firmware that allows you to program other AVR microcontrollers.

The new zip file (avrisp.01.zip) should compile on the current Arduino IDE, and I changed the comments that put the wrong labels on the SPI pins. Go ahead with this file if you use Tiny13, Tiny2313 etc. (any AVR with a 32 byte/16 word page size)

I'm building an Arduino for William on the Evil Mad Scientist business card. Monday I added the six pin ISP port to the card and built a cable for it. I took a 40 pin IDE cable and cut off one end of it. Then I soldered the other end to a pin header that I could plug into the Arduino.

I thought that my Mega8 chip was damaged because when I flashed it parts of the memory were not written. I tried using a fresh Mega168 chip and got similar results, so I took a second look at the software. When I developed the Arduino AVRISP emulation I was using chips with a 16 word page size. That means you write the flash 16 words (32 bytes) at a time. I had hardcoded that page size in my software. But the Mega8 uses a 32 word page size. My software would fill the zero page fine, then skip the bottom of page 1, resulting in the empty memory rows.
I already had the page size (AVRDUDE sends it to the programmer) so I just needed to change a function to return the correct current page based on the page size (instead of the hard coded 16 word page size).

It took some work to figure this all out. I even used Powershell at one point: I was wishing for a list of Atmel AVR chips with their flash page sized, when I realized that all the information is in avrdude.conf. I just had to find a way to summarize it. Powershell select-string saved the day select-string ("description", "paged", "page_size") avrdude.conf.

I saw that the various chips with paged flash use pages from 16 to 128 words, so I updated the current_page() function with the appropriate sizes and bitmasks. I would like to just calculate the bitmask, but with just a handful it was clearer just to return a value based on the current page size.

The updated code works with Mega8 (and should for Mega168 and other AVR Mega chips) and is available in the project SVN.

I'm building a project using the AVR ATMega8 microcontroller. Once I got the thing wired up to where I could write firmware to it I found that it was always failing. I made a .hex file full of 0x10 values (256 bytes worth) and tried uploading that to the chip. The 0x20, 0x60, 0xa0, and 0xe0 lines were still blank (0xff). I guess the chip has some problems, so I rewrote my firmware to avoid the bad sections. I put the main routine at 0x30 and the sleep routine at 0x70. I found that the assembler uses word addresses, and that .org 0x70/2 is a valid address. I changed it to 0x38 just because the calculated address was weirding me out.

Then it also turns out I forgot to initialize the stack pointer (two bytes on Mega8 by the way). Got that fixed, adjusted the timing, and now it's working. Unfortunately I didn't select matching LEDs when I build the circuit board, so I think I'm going to start over with a new board, new LEDs and maybe even a fully functional Mega8 chip.

I'm building an Arduino-compatible board for William. I'm building it on the Evil Mad Scientist MegaXX8 business card. It will have four built-in LEDs and a USB interface. It will also have connectors so he can use it with a breadboard. Perhaps we can connect it to some of his LEGO projects.

William wants a laptop. He thinks it would be cool if we could build one for him...