MID codes for machine identification

MID codes for machine identification

These are useful in order to support the different machines within the F256 class of machines, as they don't have the exact same devices, sound options and whatnot. For a detailed list of what is supposed to be available, read on this page on hardware details. Additionally, the specific FPGA core that is currently running will affect the following ID that is found in this table. For completeness, other computers from the Foenix Retro Systems are included, but they are not otherwise covered in this wiki you're currently reading. The current wiki tries to cover the F256Jr., F256K, F256 Jr.Jr. and F256K2. For all other computers mentioned in this table, you can refer to the older wiki found at [| wiki.c256foenix.com].

To get one of the following Machine ID, check the read-only register address of 0xD6A7 and check bits from 0 to 4. Initially, a 0x1F mask was applied to the value read from 0xD6A7.

However, bit 5 was recently added to account for some cores of the Jr.2 so that they are different from the equivalent of the original Jr. Bits 6 to 7 are unused for this process.

Bit5	Bit4	Bit3	Bit2	Bit1	Bit0	Hex using 0x1F mask	CPU	Machine
0	0	0	0	0	0	0x00	65816	C256 FMX
0	0	0	0	0	1	0x01	65816	C256 U
0	0	0	0	1	0	0x02	6502/65816/6809	F256 Jr. with classic mmu
0	0	0	0	1	1	0x03	65816	F256 Jr. extended memory map
1	0	0	0	1	1	0x02	65816	F256 Jr.Jr. with classic mmu (65816)
1	0	0	0	1	1	0x03	65816	F256 Jr.Jr. with extended memory map (65816)
0	1	1	0	1	0	0x1A	6809	F256 Jr.Jr. with 6809 core
0	0	0	1	0	0	0x04	65816	Gen X
0	0	0	1	0	1	0x05	65816	C256 U+ (4M SRAM)
0	0	0	1	1	0	0x06		Reserved
0	0	0	1	1	1	0x07		Reserved
0	0	1	0	0	0	0x08	68xx0xx	A2560 X (GenX 32Bits Side)
0	0	1	0	0	1	0x09	68EC000	A2560 U+
0	0	1	0	1	0	0x0A	68LC060	A2560 M (launch in 2025)
0	0	1	0	1	1	0x0B	68040RC25V	A2560 K (classic)
0	0	1	1	0	0	0x0C	68040FE33V	A2560 K40
0	0	1	1	0	1	0x0D	68LC060	A2560 K60
0	0	1	1	1	0	0x0E		Undefined
0	0	1	1	1	1	0x0F		Undefined
0	1	0	0	0	0	0x10	65816	F256P (future portable?)
0	1	0	0	0	1	0x11	65816	F256K2 with classic mmu map
0	1	0	0	1	0	0x12	6502/65816/6809	F256K with classic mmu map
0	1	0	0	1	1	0x13	6502/65816	F256K with extended map
0	1	0	1	0	0	0x14	65816	F256K2 with extended map
0	1	0	1	0	1	0x15		Reserved
0	1	0	1	1	0	0x16	6809	F256K2 with 6809 core
0	1	0	1	1	1	0x17		Reserved

Additional registers for machine information

Note that these are all read-only registers.

Address	Name	Description
0xD6A8	PCBID0	ASCII character 0: "B"
0xD6A9	PCBID1	ASCII character 0: "0"
0xD6AA	CHSV0	TinyVicky subversion in BCD (low)
0xD6AB	CHSV1	TinyVicky subversion in BCD (high)
0xD6AC	CHV0	TinyVicky version in BCD (low)
0xD6AD	CHV1	TinyVicky version in BCD (high)
0xD6AE	CHN0	TinyVicky number in BCD (low)
0xD6AF	CHN1	TinyVicky number in BCD (high)
0xD6EB	PCBMA	PCB Major Rev (ASCII)
0xD6EC	PCBMB	PCB Minor Rev (ASCII)
0xD6ED	PCBD	PCB Day (BCD - Binary Coded Decimal)
0xD6EE	PCBM	PCB Month (BCD)
0xD6EF	PCBY	PCB Year (BCD)

Special case of the F256K2 optical keyboard with a small LCD screen

Since the machine can lock up if you try to access the case-embedded LCD screen found (so far) only on the F256K2 with an optical keyboard, you must test a special bit in order to find whether it is an older style mechanical keyboard, or the newer style optical keyboard. All K2 at release in 2025 and on have them, so for those, testing the machine MID code would be enough. However, there are K2b boards released in late 2024 which were meant to give early access to the K2 machines, but they were meant to be temporarily used in the older F256K cases that have mechanical keyboards. Therefore, this following test must be performed to avoid locking up a machine that would attempt to access a non-present case embedded LCD.

Poll address 0xDDC1 and test bit 1 (second to last least significant bit).

If bit1 is set to 1 (ie 0bxxxxxx1x), the keyboard is mechanical and the embedded LCD is not available.

If bit1 is cleared to 0 (ie 0bxxxxxx0x), the keyboard is optical and the embedded LCD is available.