84PCE:Ports:1000

Synopsis

Port Number: 1000-1FFF

Memory-mapped Address: E00000

Function: Flash Controller

Parallel Controller

For more information see the parallel commands.

Port	Default	Bits	Information
1000	01	01	Reset bit 0 to crash. Seems to reduce minimum flash wait states to 2.
1001	00	??	Freeze if write value greater than 3F
1002	06	0F	Mapped flash chip address space size.
1003	00	FF	Latches value written
1004	00	FF	Latches value written
1005	00	FF	Added flash wait states over 5.
1006	00	FF	Latches value written
1007	FF	FF	Latches value written
1008	00	01	Latches value written
1009	00	FF	Ports 1009-100F latch value written

Serial Controller

Only used in HW revisions M and later (NB: all python edition calcs are M+).

For more information see the serial commands.

Port	Default	Bits	Information
1005	00	FF	Probably ignored for compatibility with the parallel interface.
1010	00	01	Latches value written
1011	00	FF	Ports 1011-1017 latch value written
1800	00000000	FFFFFFFF	Extra data to send after command byte (usually used for a flash address).
1804	00	07	How many bytes from ports $1800-$1803 to send after the command byte.
1805	00	00	Unknown, something to do with the current flash command, always seems to be $00.
1806	00	07	Number of dummy bytes after command byte.
1807	00	11	Unknown, something to do with the current flash command. Bit 0 is always set and bit 4 is rarely set.
1808	00000000	FFFFFFFF	Number of bytes to transfer through port $1900 with the current flash command.
180C	00	C6	Bit 1 might be direction (0 = in, 1 = out). Other bits unknown.
180D	0000	B000	Unknown, something to do with the current flash command, usually $0000, rarely $B000.
180F	00	FF	Current command byte.
1818	00	03	Bit 0/1 is set when bytes can be written/read through port $1900.
1824	00	01	Bit 0 set when the command finishes and the busy bit is cleared, write 1 to clear.
182C-182F	FFC00000	FFFFFFFF	Address mask for memory-mapped access to flash.
1830	00000000	FFFFFFFF	Unknown.
1900	00	FF	Read or write command data.