Search found 204 matches

by myelin
Fri Dec 15, 2017 11:58 pm
Forum: hardware
Topic: Open Source Logic Analyzer Experiments
Replies: 98
Views: 3641

Re: Open Source Logic Analyzer Experiments

Boards are here! May have time to get one built and tested next week, otherwise sometime after Xmas :)
2017-12 fx2tube sm.jpeg
by myelin
Thu Dec 14, 2017 7:42 pm
Forum: hardware
Topic: Fast serial port/SD card adapter for the 1MHz Bus
Replies: 5
Views: 395

Re: Fast serial port/SD card adapter for the 1MHz Bus

Let's talk about construction here! Daniel has his boards, which means Dominic's probably arrived a week or so ago. Firstly: the details are always at http://myelin.nz/acorn/bbcserial -- that'll always redirect to the best location for the board. I'll update that with a proper bill of materials some...
by myelin
Thu Dec 07, 2017 9:00 am
Forum: hardware
Topic: Open Source Logic Analyzer Experiments
Replies: 98
Views: 3641

Re: Open Source Logic Analyzer Experiments

I just sent off the PCB order for the fx2_tube_cartridge_adapter to Seeed. Fingers crossed! I ended up managing to implement everything I was hoping for -- - FX2 wiring for BBC via Tube port, Electron via cartridge interface (with clock fixup), Master via cartridge interface - PiTubeDirect level shi...
by myelin
Sat Dec 02, 2017 1:12 am
Forum: hardware
Topic: Fast serial port/SD card adapter for the 1MHz Bus
Replies: 5
Views: 395

Re: Fast serial port/SD card adapter for the 1MHz Bus

I just posted one of these off to Dominic Beesley, and it appears that a single PCB just counts as a "letter" to the USPS, which means I can post them out pretty cheaply to anyone who wants one. I don't have time to assemble them, but if anyone wants a bare PCB, PM me an address and I'll p...
by myelin
Fri Dec 01, 2017 10:32 pm
Forum: hardware
Topic: Tube Detect code
Replies: 14
Views: 322

Re: Tube Detect code

It looks like the 65SC12 can take TTL levels on all its pins except PHI2. Good shout - I didn't know that - I'd read that the SC was all TTL somewhere but possibly not. I'm working away next week but when I get back I will be taking the master down to my other house to desolder the CPU, I will see ...
by myelin
Fri Dec 01, 2017 6:54 pm
Forum: hardware
Topic: Tube Detect code
Replies: 14
Views: 322

Re: Tube Detect code

PiTubeDirect and the Matchbox Co Pro use the 74LVC4245 Gosh. Those are usefully cheaper, thanks. ... and also TTL compatible. The 74LVC*T245 chips have Vih=0.7*VCC for the 4.5-5.5V range, so they won't work with TTL signal levels (they'll output 5V but won't register a 2.5V input level as high). Th...
by myelin
Thu Nov 30, 2017 11:33 pm
Forum: hardware
Topic: Open Source Logic Analyzer Experiments
Replies: 98
Views: 3641

Re: Open Source Logic Analyzer Experiments

That's a two drive (40 conductor) IDE cable. I guess that answers my question! No point adding a second Tube connector onto the board if any IDE cable will do the same thing. It looks like some IDE cables have pin 19 blocked out, and some have pin 28 open circuit on the far end of the connector, fo...
by myelin
Thu Nov 30, 2017 5:59 pm
Forum: hardware
Topic: Open Source Logic Analyzer Experiments
Replies: 98
Views: 3641

Re: Open Source Logic Analyzer Experiments

Will it be possible to pass-thru the tube _and_ have a logic analyser at the same time? I might be looking to debug tube transfers and code running on the I/O processor...if not I'd say it is probably an edge case. It should absolutely be possible to do that if your Tube device is a Raspberry Pi, o...
by myelin
Thu Nov 30, 2017 1:21 am
Forum: hardware
Topic: Open Source Logic Analyzer Experiments
Replies: 98
Views: 3641

Re: Open Source Logic Analyzer Experiments

You could save one pin by dispensing with RST out from the CPLD, and then level shifting RST in another way, e.g. a schottky diode and a pullup resistor to 3.3V. I like this plan. I think this would actually save two pins, because the CPLD doesn't have any state aside from the clock latch, so it ca...
by myelin
Tue Nov 28, 2017 1:49 am
Forum: hardware
Topic: 6809 experiments
Replies: 132
Views: 6702

Re: 6809 experiments

crj wrote:How do I know this? Well... it's possible we should be avoiding duplication of effort!


Excellent... I'll stop thinking about this one and concentrate on finishing the six or so things I'm already pottering around on!
by myelin
Tue Nov 28, 2017 12:55 am
Forum: hardware
Topic: 6809 experiments
Replies: 132
Views: 6702

Re: 6809 experiments

Yes exactly, the only remaining stocks have 2x female DIL headers on the bottom, not the 40-pin DIP male header. I don't think any more are being made. Time for us to make our own miniature FPGA board perhaps? The XC6SLX9-2CSG225 is 13x13mm, which will (just) fit between two rows of 15.24mm pins. A...
by myelin
Mon Nov 27, 2017 10:58 pm
Forum: hardware
Topic: Open Source Logic Analyzer Experiments
Replies: 98
Views: 3641

Re: Open Source Logic Analyzer Experiments

That would be a very nice board! How do you get to 34 I/Os? PiTubeDirect needs 15 on each side: D[7:0] A[2:0] nRST nTUBE RnW Phi2 (aka 2MhzE) Which is 30 in total, plus the 16MHz clock makes 31. (A3 is nice to have, but not essential, IRQ into the host is not used) You can see them here: https://gi...
by myelin
Mon Nov 27, 2017 7:55 pm
Forum: hardware
Topic: Open Source Logic Analyzer Experiments
Replies: 98
Views: 3641

Re: Open Source Logic Analyzer Experiments

I've done three runs of the Dormann tests on each configuration and, once locked on to the instruction stream, the bus decoding was error free in all cases. Which is confirmation that the only issue was the Phi0 clock quality, and that the AP5's clock regeneration scheme is reliable. Excellent! Sou...
by myelin
Mon Nov 27, 2017 4:40 pm
Forum: hardware
Topic: Open Source Logic Analyzer Experiments
Replies: 98
Views: 3641

Re: Open Source Logic Analyzer Experiments

I wonder if something like this would help (run off 3.3V, otherwise the switching threshold is a bit high)? https://www.ti.com/lit/ds/symlink/sn74lvc1g17-q1.pdf Or would it be better to stick to the slower 74LS14? Alternatively a 9536 with the clock cleanup VHDL you wrote for the AP5, maybe? There'...
by myelin
Sun Nov 26, 2017 8:04 pm
Forum: hardware
Topic: Open Source Logic Analyzer Experiments
Replies: 98
Views: 3641

Re: Open Source Logic Analyzer Experiments

Dave — you’ve probably already given this a try, but if not, can you verify that PHI0 works as well as PHI2 as the capture clock? I assume you’re using an IC clip to do your Elk captures, in which case you should just be able to move two pins over to switch clocks. This is the last thing that could ...
by myelin
Sun Nov 26, 2017 7:12 pm
Forum: hardware
Topic: Open Source Logic Analyzer Experiments
Replies: 98
Views: 3641

Re: Open Source Logic Analyzer Experiments

Thanks Dave! Looks like I don’t need to worry about adding extra components, which is nice. I’ll update the netlist to match your last post. Will have some time to lay out the PCB today or Tuesday!
by myelin
Sat Nov 25, 2017 7:59 am
Forum: hardware
Topic: Open Source Logic Analyzer Experiments
Replies: 98
Views: 3641

Re: Open Source Logic Analyzer Experiments

If we’re not shooting for a wires-only design, the ideal would probably be to put a small CPLD (9536/72?) between the tube/cartridge interface and the FX2, and buffer *all* the signals at 2MHz, not just 16 of them. If the FX2 can trigger off the falling PHI0/2 edge, maybe we can use its third input ...
by myelin
Fri Nov 24, 2017 6:57 pm
Forum: hardware
Topic: Open Source Logic Analyzer Experiments
Replies: 98
Views: 3641

Re: Open Source Logic Analyzer Experiments

Could the cartridge adapter also have space for the level shifters and a pizero? You want one of my Elk PiTubeDirect boards, which uses a CPLD for level shifting and to provide the /TUBE signal. Dave Hitchins has a few of them — ping him and he’ll post you one. They’re just bare boards but as long ...
by myelin
Thu Nov 23, 2017 10:54 pm
Forum: hardware
Topic: Open Source Logic Analyzer Experiments
Replies: 98
Views: 3641

Re: Open Source Logic Analyzer Experiments

If you do come up with a working open source PCB (say in KiCad). I would be happy to commission a batch of boards from China and distribute those in the UK for free or at cost. ( https://pcbshopper.com/ ) :D That would be excellent! Not done yet, but here's the current design: https://github.com/go...
by myelin
Thu Nov 23, 2017 8:48 pm
Forum: hardware
Topic: Open Source Logic Analyzer Experiments
Replies: 98
Views: 3641

Re: Open Source Logic Analyzer Experiments

Tube lcsoft board Cartridge ------ ------------ ---------------- Pin 2 (RnW) -> PD0 <- (RnW) Pin A4 (Elk)/Pin A11 (Master) PD2 <- (Rdy) Pin A11 (Elk)/via wire/test Clip (Master) Note that the cartridge pin for RnW differs between the Elk and Master. Sounds good. I'll add in some jumpers so you can ...
by myelin
Wed Nov 22, 2017 11:57 pm
Forum: hardware
Topic: Open Source Logic Analyzer Experiments
Replies: 98
Views: 3641

Re: Open Source Logic Analyzer Experiments

Maybe a PCB with both a tube connector and a cartridge slot can be made to allow Beeb, Master and Electron to be monitored? Good thinking. It would look a bit odd but would work well! Cartridge connector on one side, Tube cable header on the other, and header for the lcsoft FX2 board in between. I'...
by myelin
Wed Nov 22, 2017 6:36 pm
Forum: hardware
Topic: Open Source Logic Analyzer Experiments
Replies: 98
Views: 3641

Re: Open Source Logic Analyzer Experiments

An Electron version could use the cartridge interface, too. And there's always the Electron and Master Compact expansion connectors, although I haven't really looked at the latter in any depth, but I guess that it is easily good enough for this hardware's requirements. The cartridge interface shoul...
by myelin
Tue Nov 21, 2017 10:08 pm
Forum: hardware
Topic: loading UEF images into the Elk with UPCFS on EUP
Replies: 48
Views: 3316

Re: loading UEF images into the Elk with UPCFS on EUP

You could do this without a second cartridge by loading UPURS into one SWRAM bank, loading one ROM image into the other bank with *UPLOAD, loading the second ROM image at &2000 with *UPLOAD, then copying the second ROM image over the top of UPURS in your first SWRAM bank. That said, the sweet sp...
by myelin
Tue Nov 21, 2017 9:41 pm
Forum: hardware
Topic: Electron 6502 desolder / socket pics
Replies: 11
Views: 548

Re: Electron 6502 desolder / socket pics

Maybe someone could do this as their next project giving you highrise options for your CPU boards. :lol: Could work! My keyboard extender cable (the rainbow coloured ribbon visible in the pic) has effectively split my Elk into a two box solution, and with a bit of 3D printing it could be made that ...
by myelin
Tue Nov 21, 2017 8:13 pm
Forum: hardware
Topic: Electron 6502 desolder / socket pics
Replies: 11
Views: 548

Re: Electron 6502 desolder / socket pics

OK . . . Now let's see a photo with the keyboard in place =D> :lol: Hah! It won't even close with the *single* riser board (two photos up; the one with the CPU on it). I was hoping to be able to make a board that would give me all this stuff (shadow RAM, internal SD, Tube) without running into the ...
by myelin
Tue Nov 21, 2017 6:20 pm
Forum: hardware
Topic: Electron 6502 desolder / socket pics
Replies: 11
Views: 548

Re: Electron 6502 desolder / socket pics

That is... you have full control (within the limits of the CPLD... so if you want to push a 16MHz clock out through the /NMI pin, you could do that), over everything except A12:0 and D7:0. The A and D pins are wired to 74LVC245 buffers, and you have control of the /OE and DIR pins, so you can put a ...
by myelin
Tue Nov 21, 2017 5:37 pm
Forum: hardware
Topic: Electron 6502 desolder / socket pics
Replies: 11
Views: 548

Re: Electron 6502 desolder / socket pics

And is there a way to "take over" the cpu signals i.e. RnW, A, D for DMA? No plans to sell them, but if you’re happy to solder one up yourself, I can send you a PCB! I added in the ability to separate A15:13 from the CPU, so you can implement shadow ram by removing the OS ROM and driving ...
by myelin
Tue Nov 21, 2017 8:27 am
Forum: hardware
Topic: Electron 6502 desolder / socket pics
Replies: 11
Views: 548

Re: Electron 6502 desolder / socket pics

More pics to come once I get a good one of the whole setup in daylight, but here's a start: 2017-11-installed-in-electron.jpeg This is my expansion board that buffers everything from the CPU socket out for 3.3V daughterboards. It's working very nicely right now with one big chunky board sitting on t...
by myelin
Mon Nov 20, 2017 4:27 am
Forum: hardware
Topic: Mods and ROMS
Replies: 13
Views: 534

Re: Mods and ROMS

Eep, hope you feel better soon!
by myelin
Sun Nov 19, 2017 2:11 am
Forum: hardware
Topic: Mods and ROMS
Replies: 13
Views: 534

Re: Mods and ROMS

MartinB wrote:....on the Beeb and Master, all the UPURS utilities except UPCFS also have disc-based versions so the rom, whilst more convenient, isn’t essential.


Hah! I'm prone to forgetting about the existence of discs... I'll add a note to that post!

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