Firmware, SCM S5

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

NameSmall Computer Monitor
ConfigurationS5
Release 2019-06-02
DownloadSCM S5 2019-06-02
Device Programming:
Code size32k bytes
Checksum (MiniPro 6.6)07D6 357F
Recommended IC SST39SF040
Core Components:
MonitorVersion 1.0.2
BIOSZ180 native 1.0.1
Included Apps:
– ROM BASICVersion 4.7b.1
– CP/M loader from CF cardVersion 1.0

The firmware 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.

The Small Computer Monitor’s Components and Apps are described here.

Source code can be found in the Small Computer Workshop download.

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 0x00

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 Modules

  • Self-test status display:
    • RC2014, digital I/O module

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 0x40 to 0x7F.

SCM assemble and disassemble commands only support official Z80 instructions, not the extended Z180 instruction set.

Homebrew 8-bit retro computing