Performs a best-effort attempt to detect attached PSRAM, configure it and
*add* it to the MicroPython heap. If PSRAM is not present, should fall
back to use internal RAM.
Introduce two new port/board defines:
- MICROPY_HW_ENABLE_PSRAM to enable PSRAM.
- MICROPY_HW_PSRAM_CS_PIN to define the chip-select pin (required).
Changes are:
- ports/rp2/rp2_psram.[ch]: Add new PSRAM module.
- ports/rp2/main.c: Add optional PSRAM support.
- ports/rp2/CMakeLists.txt: Include rp2_psram.c.
- ports/rp2/mpconfigport.h: Add MICROPY_HW_ENABLE_PSRAM.
- ports/rp2/modmachine.c: Reconfigure PSRAM on freq change.
Co-authored-by: Kirk Benell <kirk.benell@sparkfun.com>
Co-authored-by: Mike Bell <mike@mercuna.com>
Signed-off-by: Phil Howard <phil@gadgetoid.com>
