05/21/2022 at 14:53 •
New video covering the design, assembly and testing of my new TMS9918A card just landed.
Thanks to @PCBWay Official
05/17/2022 at 01:43 •
My new 65C02 CPU card. Thanks to @PCBWay Official who has provided me with a handful of custom PCBs to replace my old hand-wired cards.
I have captured the trials and tribulations of converting the old hand-wired card to a custom PCB in the following video:
As always, schematics and code are in my GitHub repository.
05/02/2022 at 06:44 •
A new batch of five different PCBs just arrived for my HBC-56 homebrew computer courtesy of PCBWay. They look fantastic. Time to start assembling.
The five new designs (front and back from left to right)
- RAM/ROM with shadow RAM
- 65C02 / VIA / SPI / Interrupt controller
- TMS9918A VDP
- Dual AY-3-8910 audio
- PS/2 keyboard + dual NES controller
TMS9918A VDP card new versus old
Close-up view of the dual AY-3-8910 sound card.
#hbc56 #homebrew #pcbway
03/30/2022 at 04:39 •
More tinkering on the emulator for my 65C02 / TMS9918A homebrew build has resulting in many improvements to the debugger, including being able to step through the source assembly code, set and clear breakpoints, break on interrupts, examine variables and constants, RAM and VRAM, click to labels, etc.
You can try it online here: https://visrealm.github.io/hbc-56/emulator/wasm/?rom=breakout
03/02/2022 at 02:47 •
You can now run BASIC, Invaders or my Breakout clone in your browser. All 6502 / TMS9918A code is available too. A couple of limitations:
- Requires a keyboard
- No audio in the browser emulator
Try it here: Breakout on the HBC-56
02/28/2022 at 07:34 •
I've been working on some TMS9918A content for YT and in the process, threw together a Breakout clone for my HBC-56.
As always, all source code is available: https://github.com/visrealm/hbc-56
02/02/2022 at 23:43 •
I've added a MC68B50 UART to my HBC-56 and have started developing a memory monitor to run on it. Since the memory monitor can write to memory using hex strings, I've modified ACME Assembler to output in Intel HEX format and transform the output to memory monitor commands.
The result? Can now load programs (games) over serial.
I've also added UART support to my emulator and can connect to both the emulator and the real machine using PuTTY.
01/15/2022 at 10:56 •
I've finally gotten around to building out a card to hold my PS/2 keyboard controller and dual NES controller ports. This circuit has been hanging off the front of my build on breadboards for months!
12/12/2021 at 00:24 •
So, now I have a keyboard, I decided to do something to make use of it. BASIC seems appropriate, so I "ported" EhBASIC to my system, including TMS9918, character LCD and 128x64 graphics LCD drivers.
In doing so, I discovered a bug in my emulator. The BIT opcode in the 6502 library I was using didn't set the processor flags correctly. So, I tracked that down and fixed it.
All the code is available and you can follow along using my HBC-56 emulator (also in the GitHub repo).
If you've been thinking about BASIC for your 6502 build, it's not too hard to do.
12/05/2021 at 04:29 •
I've had a number of people asking for a better look at the backplane and cards. Here's a quick spin around Troy's HBC-56. A quick tour...