I've got hold of a few IS66WVS16M8FBLL chips (3.3V 16MByte), and have managed to get the
cores
to initialise them correctly. Two of them show up as 32MB, and the standard PSRAM test passes. I don't have a lot of Teensy 4.1s knocking about, so the current setup will need to be torn down to test 16+8MB, and 16+Flash. I have
not yet looked at fixing LittleFS to play nicely, but I'm hopeful that the previous wisdom in this thread will set me on the right path!
Code changes can be found
here. It'll become a PR as and when I've done more testing, and have a candidate LittleFS update to go with it. Currently it only accepts 8MB and 16MB parts, but could readily be changed to accommodate a wider range of manufacturters and sizes.
Key changes are:
- detect and size PSRAM on both sets of pads
- update FLEXSPI2 registers accordingly, if the size is not 8MB
- FLEXSPI2 region size increased to 32MB (that caused me some head-scratching for a while...)
- Linker file updated to make ERAM region 32MB