Firmware, SCM S3

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

NameSmall Computer Monitor
ConfigurationS3
Release2018-12-13
DownloadSCM S3 2018-12-13 (HEX)
Device Programming:
Code size32k bytes
Checksum (MiniPro 6.6)005D 0A3E
Recommended ICAT27C256R-45PU
Core Components:
MonitorVersion 1.0.0
BIOSS3 version 1.0.0
Included Apps:
– ROM BASICVersion 4.7.1
– 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

  • Z80 CPU (eg. Z84C00xx)
  • ACIA #1 at 0x80 (eg. 68B50)
  • ACIA #2 at 0x40 (eg. 68B50)
  • SIO #1 at 0x80 (eg. Z84C42xx)
  • CTC #1 at 0x88 (eg. Z84C30xx)
  • Digital I/O at 0x00
  • Compact Flash at 0x10 for loading CP/M

The SIO can either use the RC2014 addressing scheme or the typical Zilog scheme (as used by Dr. S. Baker’s SIO 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.

Supported Modules

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.

Homebrew 8-bit retro computing