5 ms·
I’ve replaced battery backed SRAM in several game consoles and other devices with FRAM (Neo Geo CD, Sega Saturn, an HP oscilloscope) and for some it’s drop-in,
by polpo 2y ago
I’ve replaced battery backed SRAM in several game consoles and other devices with FRAM (Neo Geo CD, Sega Saturn, an HP oscilloscope) and for some it’s drop-in, and in a few you have to bodge some lines.
- rbanffy 2y agoWon’t that negatively impact the life expectancy of the device? FRAM is rated for trillions of reads and, if the SRAM is frequently read, a trillion reads isn’t that much.
- formerly_proven 2y ago>100 trillion reads per location over 30 years still means you gotta read locations at over 100 kHz 24/7. Not good enough for main memory, sufficient even for frequently accessed configuration values.
- rbanffy 2y agoDefinitely not for running code directly from it (unless it's shadowed to RAM), but for storing config data or checkpoints, it makes sense.
- seritools 2y agoI guess it depends on whether the game cartridges only use it for storing savegames, or as actual additional RAM.
- rbanffy 2y agoYes. It'd be a problem for running code directly from it - it'd be better to cache it to DRAM so that all reads would come from DRAM and only writes would make it to FE-RAM. IIRC, it was a common trick with 286 and 386 PCs, because BIOS ROMs were 8-bit wide and shadowing the BIOS in RAM made it much faster.