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First Steps

A project log for Cat-644

An 8-bit computer based around an AVR ATMega-644 and junk-box SRAM.

Mark ShermanMark Sherman 08/06/2014 at 16:280 Comments


USPS package tracking: belmont-> san francisco->oakland->emeryville->oakland->emeryville->oakland
I live in oakland. The mail truck is driving in circles!

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Well, I have 64k of flash, 4 k of ram and 1mhz 8 bit cpu... blinking an LED.

No dev board kit or arduino babyware, just a raw microcontroller on a protoboard with a self-built programming cable. Next up, 20 mhz external oscillator, and an rs232 port. Actually the max232 chip has 4 level converters in it, so why not, I'll give this 8 bit machine com1 and com2, in an age where you're lucky if your new computer accepts a usb to comm adapter without windows barfing error messages at you.

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It seems to be working. 20 mhz 8-bit Atmel AVR with 64k flash, 4K sram, currently single rs232 port. The empty socket is where the 128K sram will go. One instruction per clock vs the 6502's 2 clocks per instruction, making this 22 times faster than a 1.8 Mhz Nintendo.

20.001 MHz external clock  ( shown on old heathkit freq. counter. )

This old Heathkit frequency I got from ebay is proving useful.


Breadboard:

A simple serial test program running over Hyperterminal.

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