# Programming several AVR MCUs simultaneously? (with parallel)

I was able to program three ATMEGA32 simultaneously using ISP.

In your opinion, can I program several AVRs at once with parallel? Unfortunately, I do not have a parallel programmer. Can you test it for me?

I don't know, how it's work? I already thought it shouldn't work! How many MCU can I program together?

• I made some edits, but your question is still somewhat chaotic. You may want to ask explicitly about parallel programming and why your multi-SPI programming method worked. – Rev1.0 Sep 16 '13 at 14:13
• Haha, these pictures are from 1980. Cool! – dext0rb Sep 16 '13 at 15:43
• The problem I see is the internal oscillator that runs free at around 1, 2 or 8MHz and I know by own experience that it jitters a lot. This means that the AVR output signals will not be in sync. I don't know what that means for programming, but it doesn't sound reliable. – jippie Sep 16 '13 at 15:43
• @dext0rb oh! dextorb! :D! – brian Sep 16 '13 at 16:41
• I do not know if this is still active after all that time but hey ccheck this link: from adafruit. learn.adafruit.com/mass-avr-isp-programmer – StanDaStack Oct 3 at 2:13

If you use sufficiently conservative timings and ignore the MISO pins on all but one of the MCUs, it’s possible that you could program them in parallel. However, I don’t see how you could verify them in parallel unless you break out every MISO pin onto a separate pin and somehow check them all.