pyi2cflash 0.2.2

I2C eeprom device drivers (pure Python)

I2C eeprom device drivers (pure Python)

I2C flash devices, also known as DataFlash are commonly found in embedded products, to store firmware, microcode or configuration parameters.

PyI2CFlash comes with several pure Python drivers for those flash devices, that demonstrate use of I2C devices with PyFtdi. It could also be useful to dump flash contents or recover from a bricked devices.

Supported I2C flash devices

Vendor	Microchip	Microchip	Microchip	Microchip	Microchip	Microchip	Microchip	Microchip	Microchip	Microchip
EEPROM	24AA01	24AA02	24AA04	24AA08	24AA16	24AA32A	24AA64	24AA128	24AA256	24AA512
Status	?	?	No	No	No	Ok	?	?	?	?
Size	128	256	512	1Ki	2Ki	4Ki	8Ki	16Ki	32Ki	64Ki

Notes about performances

• Read operation is synchronous with I2C bus clock: it therefore only depends on the achievable frequency on the I2C bus, which is bound to the highest supported frequency of the flash device.

• Write operation depends mostly on the flash device performance, whose upper limit comes mostly from the maximum write packet size of the device, as the device needs to be polled for completion after each packet: the shorter the packet, the higher traffic on the I2C and associated overhead.

Notes about 24AA32

This device is declared obsolete by the manufacturer and is not supported.

Only 24AA32A revision is supported.

Supported I2C flash commands

Read

Read byte sequences of any size, starting at any location from the I2C flash device

Write

Write arbitrary byte sequences of any size, starting at any location to the I2C flash device

Dependencies

• Python 3.5 or above is required.

• PyFtdi 0.42 or above is required.