This module from Shiela Dixon (Peacock Media) is a graphics card for the RCBus.

I highly recommend this module

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Update, May 2025

A new version of the TMSEMU3 firmware adds a configuration screen to set terminal text colour, terminal text rows (24/48), and keyboard layout (US/UK). The firmware update is really quick and easy. Great update.

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Original review, Mar 2025

The module provides colour graphics (256×192) and an 80 column serial terminal. It is available from Tindie and is supplied assembled and tested. You will need a USB adapter cable – see product documentation.

I use the module without the mode jumper fitted. In this configuration it starts up in 80 column serial terminal mode, using the primary serial port at 115200 baud. Note, you may need to add jumpers to the serial module to connect the serial port to the RCBus. When graphics software is executed the module automatically switches to graphics mode (see below for limitations of automatic mode switching).

The module should work with most, if not all, RCBus systems with a Z80 CPU running at 7.3728 MHz. When using a faster CPU, such as a Z180 running at 18.432 MHz, it can be unreliable in graphics mode. However, it does appear reliable if wait states are added. To add wait states to a Z180 system running RomWBW (tested with RomWBW v3.4), enter the following command before using graphics mode:
CPUSPD Full,2,2

Testing

I’ve given this module some basic testing with several of my systems: SC600 based Z80 system and SC126 based Z180 system. I tested terminal mode (with RomWBW 3.4 and SCM v1.3) and graphics mode (with the example programs Simon and Plasma). I’ve only tested with the I/O ports set to 0x08/09.

Terminal mode works great except the keyboard mapping appears to be USA standard, not UK standard, so a couple of character positions are swapped. This can be corrected with a firmware update.

Graphics mode works well for 7 MHz Z80 systems and Z180 systems with wait states added.

Limitations

Typically, RCBus systems use a modern computer as a serial terminal. This has the benefit of allowing file transfer to and from the modern computer. When the serial terminal function is provided by the TMSEMU3 module instead of the modern computer you can no longer transfer data. One solution is to connect the modern computer to a second serial port when file transfer is required.

Automatic mode switching generally works well but not in all cases. It is desirable to fit a jumper or mode switch to lock the required mode. Another option is to run a very simple program to make a clean switch before graphics software is run.

Warnings

This module’s component height makes fitting in my compact style backplanes (0.6 inch module spacing) rather tight. If fitted between other modules I recommend putting some insulating material between the modules to prevent shorting. eg. a sheet of paper.