keith
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...
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...
New SRAM PCB is being built
So up to two SRAMs can be installed on this tiny 2″ x 2″ board. To the right is the connector, and the SRAMs are on the left. With current SRAM sizes, you can install 32-megabit SRAMs. That’s 4...
J68 can now speak with BEMICRO MAX 10 onboard SDRAM
So for the longest time, I’ve wanted to use the onboard 8MB SDRAM that is present on the BEMICRO MAX 10 fpga eval board. This is now a reality! I’ve successfully integrated a controller with some glue logic...
Modified memory controller now functioning on BEMICRO MAX 10 board
So after some minor heartache, I’ve managed to get a working memory controller on the BEMICRO Max 10 board that is easy to use. It uses a wishbone interface. The heart of the controller is from here but there were...
Something old, something new: building a NAS with a few older parts
About eight years ago, I bought a Dell XPS 420 pictured above. This was an Intel Core 2 Quad Q9550 running at 2.83ghz. With 8GB of ram. Despite running reliably for over 8 years, the main problem was that the case was a...
New project: modifying Logitech C920 webcam for PCB inspection
I’ve recently spent some time modifying a Logitech C920 webcam for PCB inspection and soldering. Head over to the page for project pictures, links to the various components, tricky gotchas I found during...
Memory controller work continues….workaround 4MB SRAM add-on
SO here’s a couple hundred dollars of SRAM parts ordered to add on to the FPGA. It goes like this: the memory controller isn’t fully integrated yet into the J68 soft-core, so I’ve decided to whack on 4...
Cirrus Logic CS4335 DAC problems finally identified and fixed.
I had some assistance in fixing this problem. My always helpful friend Brian from Canada as well as some help from Steve @ the Audacity forums contributed to solving the problem. They filled in some blanks for me, and...
left-justified DAC problems continue
Here you see the analog sound waveform coming out of the DAC at the top in yellow. I think I’m getting closer……I switched from the I2S DAC to a left-justified DAC just because the LJ one is a little...
