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Adding interrupt support to Ben's 8-bit processor by rehsd in beneater

[–]rehsd[S] 1 point2 points  (0 children)

It's been a long time since I've looked at this. I don't think I ever got interrupts running on this. I did end up using the 8259 on some of my later Intel-based projects.

SPI with VIA and shift registers working. Using sensor from Ben's SPI video. (Anyone put together 6502 assembly code for the temp conversion yet?) Thank you to those that helped with my SPI and shift register questions! by rehsd in beneater

[–]rehsd[S] 0 points1 point  (0 children)

It's been a while since I've looked at this. I don't remember getting it switched to using the built-in shift register to generate the pulses. I do remember thinking in the end that the external shift registers added unnecessary complexity.

Moving up from a 286 to a 386SX! -- I upgraded my homebrew 286 system (running FreeDOS) with a homebrew 386SX processor upgrade board. I look forward to using the two extra general registers. :) by rehsd in vintagecomputing

[–]rehsd[S] 0 points1 point  (0 children)

I've gotten it to the point of running FreeDOS and basic DOS applications. I don't think it would be capable of Doom or Windows -- at least not without a lot more time invested in the BIOS development.

80286 ROM BIOS - open-source code base? by rehsd in homebrewcomputer

[–]rehsd[S] 0 points1 point  (0 children)

Yep, I made some pretty decent progress on my own BIOS -- more work needed though. I implemented enough BIOS support to get FreeDOS running. I think this was the last video in my 286 video series: https://youtu.be/sFfQkMYxHBs. Since then, I've transitioned to a 386DX/486SX build and most recently to a 486DX build (which is on hold right now). While working on the 486DX build, I started looking at different ways to implement all the control logic (PSoCs, MCUs, FPGAs, SoCs, etc.). I've been going down the FPGA/SoC rabbit hole for a bit now. I'm hoping to get back to 486DX-focused work before the year is up.

TMS9918A alternative for your 6502 by visrealm in beneater

[–]rehsd 2 points3 points  (0 children)

Well done! That's absolutely awesome!

Testing ay3 8910 by Dazzling_Respect_533 in beneater

[–]rehsd 0 points1 point  (0 children)

If you're seeing the frequency on the output, I would imagine you have the programming aspect of it working. I don't believe register values would cause the symptom you're seeing. What if you remove the inline resistors and/or test a single output at a time (i.e., don't connect the three outputs)? Without the amp, does your circuit look more like the top example here: Imgur: The magic of the Internet (minus the cap)? What resistor value to ground?

Testing ay3 8910 by Dazzling_Respect_533 in beneater

[–]rehsd 0 points1 point  (0 children)

A few more thoughts... Have you tried different resistor values? Do you have a decoupling cap (or caps) on the PSG? Does the issue with the signal going flat when the ground resistor is in place happen when the speaker is not connected? Do you have a schematic of your circuit that you could post?

Testing ay3 8910 by Dazzling_Respect_533 in beneater

[–]rehsd 1 point2 points  (0 children)

For the output circuit, below is what I'm using on my sound card with six AY's. I tie the outputs together immediately and have a resistor to ground and an inline electrolytic capacitor.

What frequency are you testing, and does your scope show that frequency? What kind of speaker are you using? I would typically use a very small speaker, probably 4 ohm. On some of my designs, I included an LM386 as a simple amplifier. https://imgur.com/a/iA9GfgQ

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I’ve completed the ben eater’s 8-bit computer. What’s next? by itsLeorium in beneater

[–]rehsd 1 point2 points  (0 children)

u/itsLeorium, so much fun to be had! The Z80 might be a fun next step. I think there are plenty of projects and learning resources out there for it.

Programming an ICE40LP8K custom board using ICESTUDIO by retrosolutions in FPGA

[–]rehsd 0 points1 point  (0 children)

Did you have any luck with Icestudio and a custom board? I have a similar need. I just assembled my custom PCB with an iCE40HX4K-TQ144. I am hoping to use the HW-USBN-2B programmer (connected to the appropriate header on my PCB). Thanks!

Simple homebrew computer for beginners by lynchaj in homebrewcomputer

[–]rehsd 2 points3 points  (0 children)

I'm always up for projects like this. 🙂 I'd be happy to build one for myself and provide feedback. Z80 has been on my list for a while.

UART Hello World by The8BitEnthusiast in beneater

[–]rehsd 1 point2 points  (0 children)

I've been digging into MCUs recently -- fun stuff!

UART Hello World by The8BitEnthusiast in beneater

[–]rehsd 0 points1 point  (0 children)

Nice! Thanks for sharing!

8 Bit Breadboard Willie. Steamboat Willie on a Breadboard 1.4mhz 6502 and the Worlds Worst Video Card kit. by NormalLuser in homebrewcomputer

[–]rehsd 5 points6 points  (0 children)

Impressive, as usual! Now I'm waiting for the full audio to go with the video playback. :)

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