TS-7840 FRAM: Difference between revisions

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The EEPROM file can be found at /sys/class/spi_master/spi2/spi0.0/eeprom, and should be accessed like a normal file to store data in the FRAM.
The EEPROM file can be found at /sys/class/spi_master/spi2/spi0.0/eeprom, and should be accessed like a normal file to store data in the FRAM.
The last byte is reserved.  This is used for [[#U-Boot Bootcount|U-boot's bootcount]].

Revision as of 17:21, 2 December 2020

This platform supports a soldered-down, non-volatile Ferroelectric RAM (FRAM) device. The Cypress FM25L16B is a 2 KiB FRAM device in a configuration not unlike an SPI EEPROM. The nature of FRAM means it is non-volatile, incredibly fast to write, and is specified with 100 trillion read/write cycles (per each of the 256 sequential 8 byte rows) with a 150 year data retention at temperatures below 65 °C. The device is connected to Linux and presents itself as a flat file that can be read and written like any standard Linux file.

The EEPROM file can be found at /sys/class/spi_master/spi2/spi0.0/eeprom, and should be accessed like a normal file to store data in the FRAM.