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Use USBtinyISP to read and write Microchip 25LCxx EEPROM devices

If you find yourself in a need to read out, or program contents of 25LC series EEPROM, and already have USBTinyISP programmer for AVR microcontrollers then this page is for you.

For schematics of USBtinyISP, see Adafruit site.

Hardware wise, it would be wise to replace R7 and R4 on USTtinyISP with a lower value somewhere around 500 ohms, as 1.5K may cause the clock signal distortion to the point wher false clock pulses will be detected, depending on your setup.

Get the software from GitHub. It is written in Python and also demonstrates use of PyUSB using USBtiny as USB connected I/O device. You may find clever new ways for using The USBtinyISP programmer.

For reference:

 AVR PORTB bit numbers            25LCxxx wiring
 in USBtinyISP                      
                                    +--------+
 0 - LED                      VCC  -+ 1    8 +- VCC
 1                            MISO -+ 2    7 +- VCC
 2                            VCC  -+ 3    6 +- SCK
 3                            GND  -+ 4    5 +- MOSI
 4 - RESET                          +--------+
 5 - MOSI
 6 - MISO
 7 - SCK

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