Headland HT12
| Bus type | ISA |
|---|---|
| Bus width | 16-bit |
| Bus speed | 32 MHz |
| 8-bit ISA compatible? | Yes |
| Manufacturer | Headland Technologies |
| Chipset | Headland Technologies HT12 |
| Compatible with | AT |
| Connectors | AT Keyboard |
| Requires -5VDC? | Unknown "Unknown" is not recognized as a Boolean (true/false) value. |
| Requires -12VDC? | Unknown "Unknown" is not recognized as a Boolean (true/false) value. |
| Config method | Jumpers, Software |
| Motherboard | |
| Form factor | Baby AT |
| Power connector | |
| CPU socket | Unknown "Unknown" is not in the list (Socket 5, Socket 7, Socket 8, Slot 1, Socket 370, PLCC68, Socket 3, PGA132, Slot 2, Slot A, ...) of allowed values for the "Has CPU socket" property. |
| ISA slots | 1 @ 8-bit 6 @ 16-bit |
| RAM slots | 4 @ 30-pin |
| Maximum RAM | 4MB 4,194,304 B |
| Boot ROM | Socket, 28-pin JEDEC, read-only |
| Manual | Vogonsdrivers |
| Driver | Vogonsdrivers |
The Headland HT12 was a chipset commonly found in many late 286 motherboards from the early 90s. These boards have either socketed or soldered CPUs, mainly Harris or AMD, which can reach up to 16MHz operation.
The maximum amount of RAM is 4MB, with hardware EMS support. These boards usually came with AMIBIOS and onboard diagnostics written into the ROM.
The manufacturer of some of these board is unknown, so it has been documented here as the Headland HT12.
Additional photos
Underside
Octek FOX II 286
- HT12 AMIBIOS.png
CMOS setup
- HT12 DIAGNOSTICS.png
Diagnostics menu
Another HT12 board
Memory
Hardware EMS
This motherboard works with the HT12 chipset drivers, which provide an EMS interface allowing a chosen amount of memory above 1MB to be accessed as EMS. Thus it is possible for this board to be configured to have conventional, EMS, XMS and Int15 extended memory available, all at the same time.
UMBs
The chipset does not natively support backfilling unused parts of upper memory with UMBs. However if EMS support is not required, third party drivers can use the hardware EMS facility to make a small amount of memory available in as UMBs.
