Misc projectsProjects

RC2014 SC Extensions (Backplane, I/O, Proto-Board)

SC129 testing

This second part about the RC2014 acording to Stephen C. Cousins deals with a few extensions.

I actually wanted to add a CF module to use CP/M, but I started with a few other additions first. Since the small 3-slot backplane was quite limited, the next step was the modular 6-slot backplane.

SC112 – Modular Backplane (6 Slots)

The SC112 module is almost identical to the SC116 module, but now provides 6 slots instead of 3. Inputs for the power supply (2.1mm barrel connector and screw terminal), as well as on/off switch and reset button are available. In addition to the 6 slots for the modules, the backplane can be expanded by attaching another backplane (e.g. the SC113 module) with the angled 2x40p socket strip attached to the edge of the backplane. To use the 3-slot backplane as an extension, you would have to replace its last slot with a 2x40p angled pin header.

As always, a detailed description and information about the module can be found on the Cousins website.

As an additional goodie, the slots can be isolated from each other with some of the signal lines using jumpers (User1-3, as well as TX2 and Rx2). Since I still haven't really understood what this is for (maybe I will find out later), I bridged the jumpers with jumpers.

Assembly was unproblematic - this time I found a cheap source  for the 2x40p socket strips (Eckstein company at Bay) and therefore did not have to file.

SC129 – Digital I/O Board

The Digital I/O Board (SC129) provides the following features:

  • 8 digital Inputs (with red status LED)
  • 8 digital Outputs (with yellow status LED)
  • Header-Pins for all In- and Output Signals
  • Configurable I/O-Adress from 0 to 255 (0x00 to 0xFF)

With the header pins, you can easily connect and experiment with a breadboard using Dupont cables.

More information at the Website of Cousins.

Also this assembly was unproblematic. You only have to pay attention to the (of course) correct polarity of the many LEDs (would be annoying to desolder 16 pieces again), as well as the horizontal mounting of the electrolytic capacitor C5 (so that the board does not become too high and does not conflict with other modules.

The test of the module is, as always, very well described on the Cousins website. In short:

The inputs can be tested quickly using the header pins. Connect the inputs with 5V - then the corresponding LED should light up. From Basic you can also quickly query the inputs via.

PRINT INP(0)

The best way to test the outputs is also using Basic

OUT 0, x

where x indicates as decimal value which LED should light up: with 1 the first, with 2 the second, with 3 the first two, etc.

SC115 – Prototype Breakout Board

The SC115 module can be used to carry out further experiments, which simply provides all the necessary bus signals via pin headers, in order to then connect them to a breadboard using Dupont cables. In addition to the taps for the bus signals, the module allows simple address decoding for the I/O ports and provides the signals /IOWR, /IORD and /IOEN.

Test of the entire system

The entire system was tested, using the new backplane, i.e. CPU module, serial module and digital I/O module. All tests were successful. The SCM monitor started and the I/Os could be addressed with Basic commands.

Future Eytensions

Since Cousins' system is compatible with the original RC2014 system, you can of course also use the modules available there for extensions. For example the CF module to implement CP/M.

However: then you should also have tried and built the original system first - just my 2 cents! But this is something for next time.

Leave a Reply

Your email address will not be published. Required fields are marked *