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263 results for “bread80”
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This feels like a good time to look at what is needed to start the #Datapoint 2200 processor.
The Datapoint has no ROM, not even a boot ROM. On reset it rewinds tape deck 1, loads the first file, and executes it. All of this is done in hardware.
🧵
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The #Datapoint 2200 gate simulator can now import data from multiple projects and I can join boards together via connectors. So I now have the Decoder, Motherboard and Processor boards imported with net data propagating across them.
Some of the nets can have multiple drivers across different boards, so the simulator needs to examine all pins across the joined nets, and propagate the results back to all pins.
I'm now adding tooling ready to try and boot the processor, such as the scaling here.
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My #Datapoint 2200 net simulator is now generating output which matches my analysis of the Decoder board schematic (see comments on the image).
One full cycle takes 80 clocks. First SYS_CLK is divided in two and split into four T states. T0 clocks a decade counter (C0..C4). Most outputs are a combination of counter and T states.
Counts 0 to 7 are when memory and/or registers are clocked (PHIxx). Counts 8 and 9 are when 'other' stuff happens (STROBEx).
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The #Datapoint processor board is large, expensive, and will take a long time to solder up. It could have errors from my transcribing the schematics or the schematics themselves. It may even have deliberate traps to stop competitors stealing the design.
I really need a way to prove the design works. I could use Logisim for that. But re-entering the whole thing would take ages, and have issues of it's own (and assuming it could cope with the design).
1/n
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Having a play with the video chip on the #Enterprise64. This is a demo from the manual which creates a text video window in the centre of the screen. The original BASIC text window is still there ‘underneath’ it. Note that the central lines of the BASIC window are still there, just being masked out by the second window.
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Having a play with the video chip on the #Enterprise64. This is a demo from the manual which creates a text video window in the centre of the screen. The original BASIC text window is still there ‘underneath’ it. Note that the central lines of the BASIC window are still there, just being masked out by the second window.
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Having a play with the video chip on the #Enterprise64. This is a demo from the manual which creates a text video window in the centre of the screen. The original BASIC text window is still there ‘underneath’ it. Note that the central lines of the BASIC window are still there, just being masked out by the second window.
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Having a play with the video chip on the #Enterprise64. This is a demo from the manual which creates a text video window in the centre of the screen. The original BASIC text window is still there ‘underneath’ it. Note that the central lines of the BASIC window are still there, just being masked out by the second window.
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Having a play with the video chip on the #Enterprise64. This is a demo from the manual which creates a text video window in the centre of the screen. The original BASIC text window is still there ‘underneath’ it. Note that the central lines of the BASIC window are still there, just being masked out by the second window.
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I finally have the Flan wired up to the RGBToHDMI. Still some sparklies on screen but otherwise looking fantastic.
And having a little explore of the BASIC. Recursive function definitions is cool. The wordiness isn’t so great though. Feels a bit like interpreted COBOL.
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I finally have the Flan wired up to the RGBToHDMI. Still some sparklies on screen but otherwise looking fantastic.
And having a little explore of the BASIC. Recursive function definitions is cool. The wordiness isn’t so great though. Feels a bit like interpreted COBOL.
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I finally have the Flan wired up to the RGBToHDMI. Still some sparklies on screen but otherwise looking fantastic.
And having a little explore of the BASIC. Recursive function definitions is cool. The wordiness isn’t so great though. Feels a bit like interpreted COBOL.
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I finally have the Flan wired up to the RGBToHDMI. Still some sparklies on screen but otherwise looking fantastic.
And having a little explore of the BASIC. Recursive function definitions is cool. The wordiness isn’t so great though. Feels a bit like interpreted COBOL.
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I finally have the Flan wired up to the RGBToHDMI. Still some sparklies on screen but otherwise looking fantastic.
And having a little explore of the BASIC. Recursive function definitions is cool. The wordiness isn’t so great though. Feels a bit like interpreted COBOL.
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The Puppy can now handle both 16 and 8 bit values. I ended up making everything 8-bit. 16 bit operations simply need to work on both halves of their data.
So moving DE to HL know generates solutions using EX HL,DE as well as two LDs. The solution with an extra load is valid since it causes different collateral. The real question is why it doesn't generate the HL L,E alternative.
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The Puppy can now handle both 16 and 8 bit values. I ended up making everything 8-bit. 16 bit operations simply need to work on both halves of their data.
So moving DE to HL know generates solutions using EX HL,DE as well as two LDs. The solution with an extra load is valid since it causes different collateral. The real question is why it doesn't generate the HL L,E alternative.
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It's also very easy to change the font size with #Firemonkey. Here's the source code displayed using 1 point text - the smallest available.
It would be very easy to use this to add one of those fancy overview windows that posh code editors have.
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I have a couple of projects which could benefit from some kind of owner draw text control. I've never done that before using #Delphi #Firemonkey.
It's actually really easy so I've been writing a simple text editor. About three days work of to get all the main cursor movements, editing, selections and scroll bars is impressive.
A bit more work with cut/paste and mouse dragging and this will be ready to use.
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Polishing off a PCB design a started a while back. This is a breadboard breakout for #AgonLight2
Silkscreen includes a cheat-sheet for port addresses and pin configurations.
High speed pins (SD card, CPU clock) are connected via normally-open solder links because you probably don't want them anywhere near a breadboard.
Top connector has the standard pinout for onwards expansion.
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Polishing off a PCB design a started a while back. This is a breadboard breakout for #AgonLight2
Silkscreen includes a cheat-sheet for port addresses and pin configurations.
High speed pins (SD card, CPU clock) are connected via normally-open solder links because you probably don't want them anywhere near a breadboard.
Top connector has the standard pinout for onwards expansion.
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Polishing off a PCB design a started a while back. This is a breadboard breakout for #AgonLight2
Silkscreen includes a cheat-sheet for port addresses and pin configurations.
High speed pins (SD card, CPU clock) are connected via normally-open solder links because you probably don't want them anywhere near a breadboard.
Top connector has the standard pinout for onwards expansion.
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Polishing off a PCB design a started a while back. This is a breadboard breakout for #AgonLight2
Silkscreen includes a cheat-sheet for port addresses and pin configurations.
High speed pins (SD card, CPU clock) are connected via normally-open solder links because you probably don't want them anywhere near a breadboard.
Top connector has the standard pinout for onwards expansion.
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Polishing off a PCB design a started a while back. This is a breadboard breakout for #AgonLight2
Silkscreen includes a cheat-sheet for port addresses and pin configurations.
High speed pins (SD card, CPU clock) are connected via normally-open solder links because you probably don't want them anywhere near a breadboard.
Top connector has the standard pinout for onwards expansion.
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That’s the surface mount soldering finished on the #d2200 memory card. When I say finished, I’ve verified that every LEDs are the same way around. I’ve not checked they’re the correct way around. I think I’ll do some testing before moving onto the through holes. #datapoint #TTLComputer
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And the current routing status. Nine pages of schematics done. Three left to go.
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And the current routing status. Nine pages of schematics done. Three left to go.
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And the current routing status. Nine pages of schematics done. Three left to go.
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And the current routing status. Nine pages of schematics done. Three left to go.
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And the current routing status. Nine pages of schematics done. Three left to go.
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I think that's enough routing for one day. This is the second page of instruction decoding. Here we have:
* HALT opcodes - there's three of them, &00, &01, &ff. I don't know why they felt the need for three. Those octal NANDs are one gate per chip which. But &ff would, otherwise, decode to LD (HL),(HL). Z80 peoples will be proud of that.
* Some branching stuff.
* Some general stuff.
* Shift and I/O stuff.(I know those comments aren't helpful. I'm tired).