I did buy a compatible 24-pin DIP clip to make it a little easier, and a little bit more reliable, to hook up the logic analyzer. The YM2612 sits on the Z80 Bus, and so there’s lots of communication not intended...
Archive - 2017
OT: Century III Mall, not quite a dead mall, but sure heading that way
Century III Mall is an ailing enclosed shopping mall located in the southern Pittsburgh suburb of West Mifflin, Pennsylvania. I lived nearby this mall, and this was definitely “our” mall for kids like me...
Learning the YM2612 with a Sega Genesis Model 1
I’m planning on using the Yamaha YM2612 FM synthesizer chip that has been used in both keyboard synthesizers, but also in the Sega Genesis consoles. The purpose is to add audio capability to my DIY Tablet computer...
Performance of the Hope Badge Computer
I’ve just managed to get some key components working this year, and as a result, the machine is becoming more usable. I wanted to measure the performance of this Frankenstein machine. Ideally, I’d use...
move.w vs move.l: The culprit of my circle problems
If you saw my recent post about malformed circles, you’ll see that I was pulling my hair out. I identified the root cause. It turns out that I was writing 0x00000fff, which caused the pixel I was setting to be...
Graphics Primitives are working, at least mostly.
So we’ve got a frame buffer now which means we can start writing 68K routines to write graphics into it. So here I’m playing around with lines and circles. I’m using a random line drawing routine from...
Frame Buffer and Text Generation now working…
Now that I have the 4MB SRAM board installed, I now have a frame buffer that can keep up with the video bandwidth rate. The resolution and color depth is currently 800 x 480 x 12-bit. The computing shield I’m...
Interesting snippet from FPGA Prototyping by Chu
This is exactly the problem that I’ve been facing for the last couple weeks. I could get the memory tests to pass at 100% if only the CPU was talking with the external SRAM. As soon as I added in my time slot...
SRAM Frame Buffer is now up and running!
Exciting times for the Hope Badge Computer. Tonight, I’ve worked out most of the kinks with interfacing the new SRAM module which you can see in posts below this, to the J68 soft-core CPU. This means that I can...
SRAM PCB built, populated, and is testing good!
The circuit board arrived from Elecrow PCB in China, and it works without modification! My friend Brian from Canada helped me out again, laying out this PCB in short order. He did a great job! Soldering the half-mm...