CoCo on a chip

So that I don’t lose track of what I have done I am going to start posting the steps I’ve gone through to get my CoCo on a Chip working.

CoCo on a Chip is a re-implementation of the Tandy Color Computer 3 using a Terasic DE0 FPGA development board and a daughterboard for connecting peripherals. The project was created by Roger Taylor and is documented at

So far I have put together all of the hardware and gotten the machine booting. Hardware setup and programming is best explained by the blog post and I followed those steps exactly.

At that point things get more difficult. You have a booting CoCo but no software. There is an SD card interface but currently the SD card must be formatted with a special format used for the DrivePak hardware that Roger created for actual Color Computer hardware.

At first I tried to use the bluetooth serial connection to connect a virtual drive using the CoCoNet server software ( I was able to get my PC to recognize the HC05 bluetooth module that is connected to the CoCo on a Chip but was unable to get a connection to the coconet software. This is something I need to explore further.

What finally worked was to download a disk image that Roger posted ( and use win32diskimager to burn it to a 2GB SD card.

Now I am trying to figure out what software is in that image and how to use it. I’ll have future posts describing my adventures with this hardware.