Search found 1026 matches

by fordp
Thu Feb 08, 2018 7:55 am
Forum: off-topic
Topic: Why did CISC prevail?
Replies: 21
Views: 1421

Re: Why did CISC prevail?

When designing the ARM Steve Furber was saying how the other processors of the day could not effectively use the available memory bandwidth and this was part of the rationale for simpler, faster instructions, i.e. RISC. RISC took off - all the Unix workstation manufacturers went for it, it was only...
by fordp
Tue Feb 06, 2018 8:23 am
Forum: hardware
Topic: Open Source Logic Analyzer Experiments
Replies: 253
Views: 17525

Re: Open Source Logic Analyzer Experiments

Seems like a plan, I do occasionally need to find out what went wrong on hardware that isn't reproducible on an emulator and this seems like one way of debugging really nasty timing issues. I also have a few beebs that need looking at, which will also be easier with this. This set-up with your ROM ...
by fordp
Sun Feb 04, 2018 11:48 am
Forum: hardware
Topic: Myelin's FX2 Tube/Cartridge Adapter - Development and Support
Replies: 46
Views: 3008

Re: Myelin's FX2 Tube/Cartridge Adapter - Development and Support

It's a pity that SYNC doesn't go through the CPLD, because it would be really easy to just latch it on the rising edge of the clock! Maybe I should have just started off with a 64-pin xc9572xl after all :) I don't suppose it's possible to configure the FX2 to sample on both edges of the clock, is i...
by fordp
Thu Feb 01, 2018 9:28 pm
Forum: wanted
Topic: Lx9pro fpga copro
Replies: 23
Views: 1645

Re: Lx9pro fpga copro

RobC wrote:
fordp wrote:Can it run PDP Basic ?
Do you mean this?

If so, yes.
Cool. I am guessing you do it via the Native Copro however?
by fordp
Thu Feb 01, 2018 9:22 am
Forum: wanted
Topic: Lx9pro fpga copro
Replies: 23
Views: 1645

Re: Lx9pro fpga copro

RobC wrote:For those without a Matchbox, I do have a PDP-11 emulator running in software on the native ARM core of the Pi-copro. It'll run a few variants of UNIX (albeit a bit slowly).
Can it run PDP Basic ?
by fordp
Tue Jan 30, 2018 1:23 pm
Forum: emulators
Topic: Keyboard Stickers
Replies: 2
Views: 517

Re: Keyboard Stickers

If they are reverse printed then they would be very durable. They are selling the sets for less than $10. If you have a spare black PC keyboard lying round I think it would be a good option.

I would guess they would fit on the cherry key caps for those wanting to make a brand new Atom keyboard too.
by fordp
Tue Jan 30, 2018 8:02 am
Forum: hardware
Topic: Electron 6502 desolder / socket pics + Max 10 FPGA in CPU socket
Replies: 34
Views: 2765

Re: Electron 6502 desolder / socket pics

When I was much much younger, I wrote to Slogger to suggest that they take the Electron mainboard out of it's case and give it a bigger one (a bit like the master compact), leaving the Keyboard where it was. Maybe someone could do this as their next project giving you highrise options for your CPU ...
by fordp
Mon Jan 29, 2018 12:54 pm
Forum: emulators
Topic: Keyboard Stickers
Replies: 2
Views: 517

Keyboard Stickers

I just noticed this from a Spectrum post on Facebook: http://www.4keyboard.com/commodore/647-3006-sinclair-zx-spectrum-non-transparent-keyboard-stickers.html#/21-size_key-11x13/32-background_color-black spectrum_overlay.jpg Maybe there would be interest in designing/ ordering something similar for A...
by fordp
Mon Jan 29, 2018 9:47 am
Forum: hardware
Topic: RGB to HDMI using a Pi Zero and a small CPLD
Replies: 787
Views: 39871

Re: RGB to HDMI using a Pi Zero and a small CPLD

It would be great to try this on my Beeb FPGA DE1, without the need for a CPLD ;)
by fordp
Thu Jan 25, 2018 9:02 am
Forum: hardware
Topic: Beeb FPGA
Replies: 498
Views: 41370

Re: Beeb FPGA

My TV works at both TV and VGA rates through the VGA input. I then use the Scart input for my real Beebs.
by fordp
Sat Jan 20, 2018 8:41 pm
Forum: hardware
Topic: Myelin's FX2 Tube/Cartridge Adapter - Development and Support
Replies: 46
Views: 3008

Re: Myelin's FX2 Tube/Cartridge Adapter - Development and Support

My board arrived, many thanks. My colleague has fitted all the small SMT components but commented there was no legend to say which round the diode should go. He was about to fit the CPLD when he realised I had got the 64pin QFP version instead of the 44 pin QFP, Doh! I will order some more chips and...
by fordp
Thu Jan 04, 2018 10:57 pm
Forum: other vintage computer hardware, software and games
Topic: Early 70s Calculators
Replies: 52
Views: 4888

Re: Early 70s Calculators

My perception from BITD: Sinclair: remarkable Commodore: affordable TI: capable HP: unattainable For some reason, Casio and Sharp didn't pique my interest much. Later on, I came to like Sharp. From my perspective, it was rather different... At school when I discovered that electronic calculators ex...
by fordp
Thu Jan 04, 2018 10:20 pm
Forum: software & utilities for the pc, mac or unix
Topic: BBC micro style keycaps for modern keyboard
Replies: 26
Views: 3282

Re: BBC micro style keycaps for modern keyboard

Maybe having the extra Atom keys made too would make it more interesting. Atoms are rare and expensive and worth remaking I think. Did I see a perspex atom case somewhere or am I making that up?
by fordp
Sat Dec 16, 2017 10:25 am
Forum: hardware
Topic: Open source firmware for Gotek floppy emulator released
Replies: 179
Views: 18768

Re: Open source firmware for Gotek floppy emulator released

https://www.ebay.co.uk/itm/3-5-Floppy-Disk-Drive-USB-Emulator-Simulation-For-GOTEK-Music-Electronic-Organ/232081793751?_trkparms=aid%3D555017%26algo%3DPL.CASSINI%26ao%3D1%26asc%3D20151016114640%26meid%3D90b66f5378c64da38f5b516a35c3c1e6%26pid%3D100507%26rk%3D1%26rkt%3D1%26&_trksid=p2045573.c100507.m...
by fordp
Fri Dec 15, 2017 3:33 pm
Forum: hardware
Topic: BBC Master screen interference PiTube direct
Replies: 57
Views: 3526

Re: BBC Master screen interference PiTube direct

Hi, When designing the first version of the master card I had the same problem, but I thought it was noise on the datalines. Because when I added the inline 330ohm resistors on the data lines the noise was gone. I will change the design and make new cards. I will see what we can do with replacing t...
by fordp
Fri Dec 15, 2017 3:31 pm
Forum: hardware
Topic: BBC Master screen interference PiTube direct
Replies: 57
Views: 3526

Re: BBC Master screen interference PiTube direct

I have have seen this on my Master with internal PI CoPro.
by fordp
Thu Dec 14, 2017 12:52 pm
Forum: hardware
Topic: Acorn's Second Processors and the Tube - what, and why
Replies: 47
Views: 5108

Re: Acorn's Second Processors and the Tube - what, and why

Nice write up Ed. Although I do need to pick up on a few points. The Tube hardware in the Beeb is not that special. There are plenty of other computers from the 1980s and 1990s that have equivalent signals available on an expansion port. And if someone wanted to, the Beeb's 1MHz bus could do a simi...
by fordp
Mon Dec 11, 2017 11:11 pm
Forum: hardware
Topic: Beeb FPGA port to Spectrum Next
Replies: 48
Views: 3309

Re: Beeb FPGA port to Spectrum Next

afraid am gonna be slacking a bit, this week. its crazy party season going on here! am booked up for the next 7 days (well 6+1 star wars film) ` an external tube connection` am a bit confused with your wording there. thats an actual circuit in the fpga? btw, with regard to cores....is there a maste...
by fordp
Mon Dec 11, 2017 2:41 pm
Forum: hardware
Topic: Beeb FPGA port to Spectrum Next
Replies: 48
Views: 3309

Re: Beeb FPGA port to Spectrum Next

That diagram does include 0 and 1 for earlier pi's they had to do some swapping about for later pi's and I think it was i2c ports that got swapped.
by fordp
Sat Dec 09, 2017 10:50 pm
Forum: emulators
Topic: Music 5000 in B-Em
Replies: 225
Views: 19210

Re: Music 5000 in B-Em

Steve, I've just been doing a bit of regression testing on the code in the sf/m4000 branch. (And also trying to get the right packages installed on my new Ubuntu 16.04 (64 bit) system.) I currently have the following in b-em.cfg: [midi] jack_enabled = 0 alsa_seq_enabled = 0 alsa_raw_enabled = 0 als...
by fordp
Fri Dec 08, 2017 9:47 am
Forum: hardware
Topic: Beeb FPGA port to Spectrum Next
Replies: 48
Views: 3309

Re: Beeb FPGA port to Spectrum Next

hoglet wrote:
Does Spectrum Next make use of Xilinx multi-boot (i.e. multiple cores in the same flash ROM)?
Dave
From what I read they seem to have some system for loading cores from the MicroSD card.

I have no idea how that could work however :(
by fordp
Fri Dec 08, 2017 9:43 am
Forum: hardware
Topic: Beeb FPGA port to Spectrum Next
Replies: 48
Views: 3309

Re: Beeb FPGA port to Spectrum Next

I am hoping this is going to be my favourite thread ever. My first computer was a Spectrum, my second a BBC B, my next toy after that a 32016 Second Processor.

The Spectrum Next should be able to do all of that ;)

Are you a backer Dave (hoglet) ?
by fordp
Fri Dec 08, 2017 8:04 am
Forum: other vintage computer hardware, software and games
Topic: ZX Spectrum next... Anybody backing ?
Replies: 143
Views: 13792

Re: ZX Spectrum next... Anybody backing ?

Maybe we need a new thread for BeebFPGA on the Next?

I have a feeling this platform will be more popular than all the others put together and more. At least for me ;)

As it is a Beeb it can go in the 8 bit hardware section :D
by fordp
Thu Dec 07, 2017 9:38 pm
Forum: emulators
Topic: Music 5000 in B-Em
Replies: 225
Views: 19210

Re: Music 5000 in B-Em

Thanks.

Each Midi byte take 320us so 3 bytes is 960us of latency as a minimum. This is for Midi from a keyboard over a traditional midi cable.
by fordp
Thu Dec 07, 2017 1:19 pm
Forum: emulators
Topic: Music 5000 in B-Em
Replies: 225
Views: 19210

Re: Music 5000 in B-Em

How does the latency compare to a pro midi synth?
by fordp
Wed Dec 06, 2017 9:03 am
Forum: hardware
Topic: Beeb FPGA
Replies: 498
Views: 41370

Re: Beeb FPGA

by fordp
Wed Dec 06, 2017 8:16 am
Forum: hardware
Topic: Pi-based Co-Pro on the cheap - 100MHz 6502 for £10? (now 274MHz)
Replies: 1159
Views: 117848

Re: Pi-based Co-Pro on the cheap - 100MHz 6502 for £10? (now 274MHz)

Hard drive access is polled, so the data is flung at the Tube at exactly the speed the hard drive chooses to make data available to the CPU. This is an issue as the ADFS hard drive transfer loop is very tight and depends almost entirely on the instructions themselves for the inter-byte delay, so if...
by fordp
Tue Dec 05, 2017 7:03 pm
Forum: hardware
Topic: Pi-based Co-Pro on the cheap - 100MHz 6502 for £10? (now 274MHz)
Replies: 1159
Views: 117848

Re: Pi-based Co-Pro on the cheap - 100MHz 6502 for £10? (now 274MHz)

Does anyone know if solidisk at 4MHz ends up overclocking the tube? If so I'm afraid it is very unlikely to ever work. I'd doubt that but it may interfere with phi1 like the WE 32K RAM does. That could throw your timing off as 2MHzE is derieved from phi1 not phi2O on the Beeb IIRC. I'd love to see ...
by fordp
Tue Dec 05, 2017 9:47 am
Forum: emulators
Topic: Music 5000 in B-Em
Replies: 225
Views: 19210

Re: Music 5000 in B-Em

Coeus will be a much better software engineer than me if he can get some code working first time without any way of testing it ;)
by fordp
Tue Dec 05, 2017 8:17 am
Forum: emulators
Topic: Music 5000 in B-Em
Replies: 225
Views: 19210

Re: Music 5000 in B-Em

I just looked at the code and it looks good to me. I am also waiting on my interface. I will try and give it a whirl when it arrives. I have no idea how to use ample / M500/M5000 however.