Another memory type that could be useful for the balloon probe is ferromagnetic RAM, or FRAM. This memory has very desirable characteristics, including low power operation, high speed, and a virtually unlimited number of read/write cycles. In fact, FRAM could be used as system memory in some applications because of these characteristics.
To test this technology out, I selected the Adafruit 32kbyte FRAM. Here is the vendor link: FRAM chip
Here are the features of this chip:
- I2C interface running at 1Mhz
- Unlike Flash or EEPROM there are no pages
- Read/write 10,000,000,000,000 times
- 256 Kbits (32 KBytes) of storage
- Individual bytes can be read or written instantly
- Data retention (without battery) for 95 years at room temperature
- Can be used with either 3 volt or 5 volts
- low power consumption especially if there are lots of reads/writes
I ran some quick tests of this board using their default code library from here: library.
There are higher capacity chips out there (256k plus bytes) but they are kind of expensive so this part will be used for testing and if there is a need the higher capacity parts can be added.