The latest release of this Firmware is detailed in the table below.
| Name | Small Computer Monitor |
| Configuration | S6 |
| Release | 2019-07-15 |
| Download ROM image | SCM S6 2019-07-15 |
| Download source code | SCW 2019-09-07 |
| Device Programming: | |
| Code size | 32k bytes |
| Checksum (MiniPro 6.6) | 07D6 2FB1 |
| Recommended IC | SST39SF040 |
| Core Components: | |
| Monitor | Version 1.1.0 |
| BIOS | Z180 native 1.1.0 |
| Included Apps: | |
| – ROM BASIC | Version 4.7b.1 |
| – CP/M loader from CF card | Version 1.0 |
The ROM image is supplied (above) as an Intel HEX format file, which is suitable for use by most PROM programmers. Intel HEX files are a text format, not a binary format. As a result they are larger than the stated code size in the table above.
Source code is supplied (above) complete with the Small Computer Workshop development environment for Windows.
The Small Computer Monitor’s Components and Apps are described here.
Diagnostic display
At reset, the 8 LEDs next to the power LED are used to display the results of the self-test diagnostics. Each LED should light for a fraction of a second and the test should end with all 8 LEDs being turned off. Failures are indicated as follows.
| Display | Issue |
| Light sequence repeats indefinitely | RAM test failed |
| LED bit 0 remains on | Serial port test failed |
| No light sequence | CPU not running, or output port failed |
Supported devices
- Z180 CPU (eg. Z8S180xx)
- Z180’s asynchronous serial ports
- Z180’s timer (for idle events)
- Digital I/O at 0x00
- Compact Flash at 0x10 for loading CP/M
- Status LEDs at 0x0D
The lack of specific support does not exclude the use of other hardware. It just means the ROM does not do anything specific with it.
Supported hardware
- Processor:
- SC126, Z180 Motherboard (Z180 CPU at 18.432 MHz)
- Memory:
- SC126, Z180 Motherboard (512k RAM, 512k ROM)
- Serial port:
- SC126, Z180 Motherboard (2 x ASCI ports)
- Timer:
- SC126, Z180 Motherboard (16-bit counter/timer)
- Baud rate generation:
- SC126, Z180 Motherboard (150 to 115200 baud)
- Digital I/O:
- SC129, Digital I/O module (8 out, 8 in, all with LEDs)
- RC2014, digital I/O module (8 x LEDs, 8 x switches)
- CP/M storage:
- Self-test status display:
- SC126, Z180 Motherboard (8 x LEDs)
The lack of specific support does not exclude the use of other hardware. It just means the ROM does not do anything specific with it.
Release notes
The Z180’s internal I/O is set to the range 0xC0 to 0xFF.
SCM assemble and disassemble commands only support official Z80 instructions, not the extended Z180 instruction set.
