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My retro computer is an SC126 designed by Stephen C. Cousins. It has two serial ports. I am using 1 serial port to interface with my retro amber monitor. That leaves the second one open to use as a way to transfer programs and data from my laptop to the retro computer. The port circled in orange is the primary serial port. I have mine plugged into the amber terminal. The one outlined in blue is used to communicate with the PC. [Read More]

I have been working with my FPGA boards to attempt to display a test pattern on a VGA monitor. For my experiments, I bought a small VGA monitor*. It has a VGA input, as well as a HDMI input, so I can use it with all of my FPGAs, since the Zybo only has HDMI ports. Hardware I am using my Mercury 2 with the Mercury baseboard attachment, as it has a VGA port on it. [Read More]

I am a big fan of retro homebrew computers. I have a few kits that I ordered from Tindie.com based on the RC2014 model (SC126). To keep it completely retro, I bought a classic amber terminal so I could have that classic user experience. After a few hours of troubleshooting, I determined that the default baud rate on the computer (115,200) was too fast for the terminal. I had to find a way to slow it down. [Read More]

I spent the evening fiddling with my Mercury 2 FPGA. I also have the Mercury Baseboard that has a VGA port (among other ports) broken out. I connected it to my monitor and started to figure out how to make it draw something. Anything would do, so I went searching for a VGA on an FPGA project that I could follow. I found one here. I had to make slight modifications to it to make it work with the Mercury 2. [Read More]

Writing C programs for speech on the SC126 (RC2014 Compatible) with a SPO256-AL2 Speech Synthesis Chip I spent some time yesterday working with ChatGPT to assist me in writing a moderately complex (based on my personal experience) C program. The program needed to be a port of the following BASIC program: 10 DATA 27,7,45,15,53,3,46,51,45,1,21,3 20 LET LE=12 30 DIM XX(LE) 40 FOR Y = 1 TO LE 50 READ XX (Y) 60 NEXT Y 70 FOR Z=1 TO LE 80 IF (INP(31) AND 2) = 2 THEN GOTO 100 90 GOTO 80 100 OUT 31,XX(Z) 110 NEXT Z This program sends the correct allophones to the speech synthesizer to make it say “Hello, World”. [Read More]