Memo fact sheet

• Code : 64k Bytes / EEPROM : 2048 Bytes / RAM : 4096 Bytes
• Homepage http://www.atmel.com/devices/ATMEGA64A.aspx
• Barely more expensive than a Atmega328 (300 JPY vs 250 JPY) but MUCH more pins ! ➩ See the dedicated board Rapide64a.
• Buy here for 300 JPY http://akizukidenshi.com/catalog/g/gI-04255/
  • Note that they sell also some ATmega64(L) : same package, exchangeable. Checked the datasheet, both are similar except the ATmega64(L) if 500 JPY (close to double price). Why? Reason is here: AVR524: Migration from ATmega64 to ATmega64A. Basically this ATmega64A is the "new" version of the ATmega64, using less current (up to nearly 70% less! even if we're talking about 2mA).

PROGRAMMING - READ ME

One VERY important thing about programming atmega64a babies : you can do it via SPI but don't use the ports MISO and MOSI ! Sounds crazy ? To me too. But read the doc !


WHAAAAAT !?? Not using MISO/MOSI but 2 other pins ! WTF couldn't you say that before I send the cards to produce in China ? Ok it's a matter of 1500 JPY but still. I spent hours (literally) searching why my cards didn't work.

... and wait, there's more !

2.3.15 PEN
This is a programming enable pin for the SPI Serial Programming mode. By holding this pin low
during a Power-on Reset, the device will enter the SPI Serial Programming mode. PEN is internally
pulled high. The pullup is shown in Figure 10-1 on page 52 and its value is given in Section
28.2 “DC Characteristics” on page 327. PEN has no function during normal operation.

WHAAAAAT !?? I have ALSO to pull that pin /PEN low when I program ??!! And cherry on the cake, that pin is dedicated to that purpose, can't reuse it ... great.
Edit: In fact it seems you don't have to bring /PEN low, it works fine if not doing it with my pololu programmer. That's one annoyance less.

FUSES - READ ME

And the fun continues : if you don't remove the Atmega103 compatibility mode M103C fuse you can have ... strange behavior. Very strange. In my case, I could call a function but the code never got OUT and the method was stuck in a loop ... wicked right ? Just unset the fuse, maybe set the clock to 8MHz oscillator at the occasion. And you're done.