atmega644v-10pu - Anyone know how to get this chip working with Arduino IDE?

I thought I ordered 4 644p's, however it turned out to be 644v's, the Sanguino stuff supports the 644 and 644p, but nothing mentioned at all about the v, also the v is rated for 10mhz, but can it do 16mhz or 20mhz?

According to the datasheets there is no difference (at least that I can tell) other then clock speed between the p and v chip...

Well, the signature bytes are different, which is fairly easily addressed.

644 0x1E 0x96 0x09 One UART

644V: 1E 96 09 One UART up to 10 MHz at 5V. May work at higher clocks, or may be unreliable as these parts likely failed screening and didn't become 644 chips.

644A: 1E 96 09 Two UARTs

644P: 1E 96 0A Two UARTs

644PA: 1E 96 0A Two UARTs

Other differences can be found with careful reading of the different datasheets. They will be subtle and likely not of interest to most users, such as brownout level operation.

Well I am pretty much new to MCU programming and hardware programming in general, so I do not really know exactly what I need to do to make the Arduino IDE talk to this chip if you could point me in a direction to take what you told me and do something useful with it :).

Are you saying the v only has 1 uart and not 2?

Yes, 644V only has 1 UART.

Install these files into your IDE https://github.com/maniacbug/mighty-1284p

check your version of avrdude.conf to make sure there is an entry that looks like this:

#------------------------------------------------------------
# ATmega644
#------------------------------------------------------------

# similar to ATmega164

part
    id               = "m644";
    desc             = "ATMEGA644";
    has_jtag         = yes;
    stk500_devcode   = 0x82; # no STK500v1 support, use the ATmega16 one
    avr910_devcode   = 0x74;
    signature        = 0x1e 0x96 0x09;

Make a new entry like this in Arduino1.0\ardware\mighty-1284p\boards.txt file

mega644.name=Mega644
mega644.upload.protocol=arduino
mega644.upload.maximum_size=64512
mega644.upload.speed=115200
mega644.bootloader.low_fuses=0xff
mega644.bootloader.high_fuses=0xde
mega644.bootloader.extended_fuses=0xfd
mega644.bootloader.path=optiboot
mega644.bootloader.file=optiboot_atmega1284p.hex
mega644.bootloader.unlock_bits=0x3F
mega644.bootloader.lock_bits=0x0F
mega644.build.mcu=atmega644
mega644.build.f_cpu=16000000L // change this to reflect the crystal you use.  I'd suggest 8 MHz.
#mega644.build.core=arduino:arduino
mega644.build.core=standard
mega644.build.variant=bobuino

The last line, mega644.build.variant=bobuino determines the pinout that will be used. Look in the variants folders Arduino1.0\ardware\mighty-1284p\variants for the pins_arduino.h file to see what those are.

"Should" be good to go from there. I don't have a 644 to try it.

Cool, I will try this out tomorrow when my crystals arrive. I just realized yesterday too that all of the datasheets I have been accumulating where just summaries, and not the entire ones!!! So now I have all of the full datasheets for the chips I have, lot’s of interesting info going on in them! (300 pages on average!!!)