84PCE:OS:Serial Flash Commands

The Python Edition calculator contains a new serial flash chip with an entirely new interface. For pre-Python calculators see the old parallel interface.

For reference, pages are 256 bytes, sectors are 4KB, and blocks are 64KB.

Basic Flash Commands

You write a command to the range $E00800-$E0080F and then wait until $E00824 bit 0 is set at which point you acknowledge by setting the same bit.

Erasing

00000000 00000001 00000000 02000006
XXXXXXXX 03000001 00000000 020000D8
00000000 00000001 00000000 04000005

X is the address of the block to erase.

Writing

Writes can only happen within a single page at a time.

00000000 00000001 00000000 02000006
XXXXXXXX 03000001 YYYYYYYY 42000032

X is the address to write to.

Y is the number of bytes to write, at most the number of bytes remaining in the page.

Afterwards, write each byte to $E00900, followed by a normal wait.