Firmware, SCM S6

The latest release of this Firmware is detailed in the table below.

NameSmall Computer Monitor
ConfigurationS6
Release 2019-07-15
Download ROM imageSCM S6 2019-07-15
Download source codeSCW 2019-09-07
Device Programming:
Code size32k bytes
Checksum (MiniPro 6.6)07D6 2FB1
Recommended ICSST39SF040
Core Components:
MonitorVersion 1.1.0
BIOSZ180 native 1.1.0
Included Apps:
– ROM BASICVersion 4.7b.1
– CP/M loader from CF cardVersion 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.

DisplayIssue
Light sequence repeats indefinitelyRAM test failed
LED bit 0 remains onSerial port test failed
No light sequenceCPU 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

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.

Homebrew 8-bit retro computing