Olivetti · M
Olivetti M300-15
25 MHz 386SX desktop with OPTi 82C283, separate 82C206 and integrated OAK OTI-067 video.
History
BA320 was initially documented with an Intel 386SX at 25 MHz; AMD 80386SX-25 was a later board-compatible alternative. Its AT bus runs at 8.33 MHz and memory populations are 4/8/10/14/16 MB.
Hardware
- Processor
- Intel 80386SX 25 MHz; AMD 80386SX-25 alternative
- Memory
- 4/8/10/14/16 MB
- Chipset
- OPTi 82C283 + separate 82C206
- Bus
- ISA/AT 8.33 MHz
- Video
- Integrated OAK OTI-067
Catalogue classification
- Form factor
- Desktop
- Mobility
- Stationary
- Processor generation
- 80386SX class
- Graphics standard
- VGA
Research
This page separates documented hardware facts, behavior observed in original firmware, and the current fidelity of BluMach emulation.
Sales and commercial configurations
Evidence: documented or confirmed hardware
- Commercial models
BA320 board with 4 MB. The service guide later adds the AMD 80386SX-25 and the ACER 87310 controller as alternatives, without changing the board level.
Architecture and memory
Evidence: documented or confirmed hardware
- CPU and bus
25 MHz Intel 386SX (or AMD 80386SX-25, a later alternative) on the BA320 board, with an i387SX socket. OPTi 82C283 memory and bus controller, and 82C206 for RTC, DMA, interrupts and timer. Four 16-bit ISA slots on the IN133 bus board.
- Memory
2 MB soldered in bank 0 and another 2 MB in SIMMs in bank 1 (4 MB standard); banks 2 and 3 take 1 M × 9 (2 MB) or 4 M × 9 (8 MB) SIMMs: 4 to 16 MB. 6 and 12 MB are not possible, and with 16 MB the 2 MB soldered are lost.
- Video
Integrated OAK OTI-067 VGA with 512 KB.
- Storage
Floppy controller and serial and parallel ports in the 87310; buffered IDE interface on the board. Documented disks are 40 to 240 MB. The BIOS reads the IDE disk geometry at startup.
BIOS and firmware
Evidence: observed in preserved firmware and boot testing
- Known revisions
BIOS 1.08 (12/04/92), 64 KB, is preserved, with a separate 32 KB EVC video ROM. The M300-08 and M300-15 images differ in only five bytes. The service guide stops at 1.07.
Emulation status
Evidence: current BluMach status; not necessarily a description of the original circuit
- Verified
POST, Calendar PASS, floppy access and MS-DOS 3.30a boot validated. With an IDE disk set to AUTO, the BIOS detects it and boots from it.
- Pending or approximate
Bootable partial emulation. The 82C283 is modelled and the AT bus is fixed at 8.33 MHz; the 82C206 and discrete controllers are represented by compatible devices. If drive 2 is set to AUTO with no disk, the BIOS waits about 11 s for it to answer, as the real machine would; with drive 2 set to "–" it does not probe it. Setup only opens on a cold boot with a configuration error and is left with ESC.
Sources
Preserved research material
Evidence: primary sources and research notes