Cloud-9 miniFLASH, User Manual

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There is a parameter block at $7100 that is referenced by the FLASH.BIN routine. That parameter
block contains the following offsets:
Offset Value
$7100 Read/Write Mode ($00 = Read ROM, $01 =
Read FLASH, $FF = Write FLASH)
$7101 Multi-Pak Slot where FLASH or ROM is
located (0-3, or $FF if no Multi-Pak is present)
$7102 FLASH bank to read/write (0-3)
$7103 Page to read/write (0-125 on a CoCo 1/2, 0-
123 on a CoCo 3)
$7104 Page size (should be 128)
$7105-06 ROM base address (usually $C000)
$7107-08 Address of FLASH Bank Selection Register
($FF49, $FF59, $FF69 or $FF79)
$7109-0A Address of a 128 byte buffer. This buffer
either contains data to write to the FLASH (in
write mode) or will hold the contents of a
FLASH or ROM page (read mode).
$710B-0C Two byte checksum of the contents of the
FLASH/ROM page (in Read Mode).
Once the parameters from $7100 to $710A have been set, the caller may JSR into the subroutine at
$7000 and the selected operation will be performed.
After reading a page of FLASH or ROM, a two byte checksum of that page is automatically computed
and stored at $710B-0C. This value is the sum of all bytes in the page, and can be used as a
verification mechanism.
Special Considerations
It is important to note that not all of the ROM can be read, nor all of the FLASH programmed. On a
CoCo 2, all but the last 256 bytes ($FF00-$FFFF) of FLASH can be read/written. On a CoCo 3, all
but the last 512 bytes ($FE00-$FFFF) of FLASH can be read/written.
The included BASIC software automatically detects the type of Color Computer being used, and
makes the proper adjustments when reading/writing FLASH. Refer to the source code for
consideration when writing your own FLASH programming software.