Firmware, SCM S2

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

NameSmall Computer Monitor
ConfigurationS2
Release2018-10-27
DownloadSCM S2 2018-10-27 (HEX)
Device Programming:
Code size32k bytes
Checksum (MiniPro 6.6)005D 5D8B
Recommended ICAT27C256R-45PU
Core Components:
MonitorVersion 1.0.0
BIOSS2 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)
  • Digital I/O at 0x00
  • Compact Flash at 0x10 for loading CP/M
  • Bit-bang serial port at 0x28
  • Status LED at 0x08

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

  • Timer:
    • not supported

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