Search found 22 matches

by Sugarplum
25 Jul 2021, 22:38
Forum: Escape Meta Alt Control Shift
Topic: Suggestions/ideas for my possible Gigatron-similar machine
Replies: 0
Views: 31

Suggestions/ideas for my possible Gigatron-similar machine

I still haven't started my Verilog CPU project. I'd like to make something that can run vCPU code, but with a different architecture. I'm looking for comments on various aspects or any considerations. Separation of video/sound/keyboard using DMA -- This will use the redirection table for the video. ...
by Sugarplum
03 Jun 2021, 19:23
Forum: Hardware and software hacking
Topic: Gigatron on an FPGA
Replies: 10
Views: 4484

Re: Gigatron on an FPGA

The image above shows this bug with all the spikes in the image around all horizontal edges. I am not sure if the double-buffering is the cause since the original design was made to work with HDMI.
by Sugarplum
25 May 2021, 21:33
Forum: Hardware and software hacking
Topic: 10MHz, 12.5MHz and Beyond!
Replies: 35
Views: 17630

Re: 10MHz, 12.5MHz and Beyond!

To go beyond a little past 12 Mhz, that is where you start to rethink other things. Redesigning the ALU to use a carry-skip adder configuration would likely help because that would allow both carry possibilities to be calculated at the same time with a minor switching delay rather than calculating t...
by Sugarplum
22 May 2021, 02:07
Forum: Hardware and software hacking
Topic: Possible ways of speeding up the Gigatron
Replies: 32
Views: 2458

Re: Possible ways of speeding up the Gigatron

Going that far, if one wants to merge the repeater board and the I/O board, one might as well boost the ALU speed too. The adders are right below the repeater, and the high adder is the one I'd replace with a reduced latency adder board. You can use 2 adders and a multiplexer in place of the upper a...
by Sugarplum
12 May 2021, 12:14
Forum: Hardware and software hacking
Topic: Possible ways of speeding up the Gigatron
Replies: 32
Views: 2458

Re: Possible ways of speeding up the Gigatron

The above is why in my FPGA design, I'd be using DMA with hardware-only syncs and moving all I/O to hardware. So everything that needs the syncs would have direct physical access to them. That would prevent hardware races. Software races would be more difficult to avoid. In this configuration, you'd...
by Sugarplum
26 Apr 2021, 20:26
Forum: Hardware and software hacking
Topic: Possible ways of speeding up the Gigatron
Replies: 32
Views: 2458

Re: Possible ways of speeding up the Gigatron

My own idea is to have concurrent DMA of some sort and clock the video side at 6.25 and/or 12.5, and generate the correct syncs. To prevent I/O races, it would probably be easier to put sound and keyboard support in hardware too. Otherwise, one would need to do parallel syncs in software, add haltin...
by Sugarplum
29 Mar 2021, 15:19
Forum: Hardware and software hacking
Topic: Hardware Interrupts
Replies: 0
Views: 496

Hardware Interrupts

While planning for doing an FPGA design, I've considered the feasibility of doing hardware interrupts. That would make it easier to separate out the video since the syncs could trigger interrupts, and it could make native coding a little easier. Now, the first thing to do is reflect on all the opera...
by Sugarplum
29 Mar 2021, 14:53
Forum: Hardware and software hacking
Topic: Possible ways of speeding up the Gigatron
Replies: 32
Views: 2458

Possible ways of speeding up the Gigatron

1. Use a faster clock rate, lower latency chips, more compact board. 2. Separating the video. This change could allow the core unit to be clocked faster than the video. I may use some type of DMA and make the controller indirection table aware in my own variation. That should keep compatibility. The...
by Sugarplum
13 Jan 2021, 19:23
Forum: Hardware and software hacking
Topic: 6Bit audio:
Replies: 9
Views: 1415

Re: 6Bit audio:

Neat! That looks a bit cleaner. I would love to hear a comparison.
by Sugarplum
23 Dec 2020, 17:22
Forum: Hardware and software hacking
Topic: List of possible Gigatron mods
Replies: 13
Views: 2919

Re: List of possible Gigatron mods

I'm still gaining ideas and working out logistics before embarking on my own creation. On the vCPU coprocessor idea, a smaller step might be just to enhance the native opcodes to have more hardware available for the vCPU, focusing on opcodes and minimal hardware that would make the current vCPU code...