Search found 7113 matches

by hoglet
Sat Jun 16, 2018 5:14 pm
Forum: software: other
Topic: BBC Micro Compendium by Jeremy Ruston
Replies: 33
Views: 943

Re: BBC Micro Compendium by Jeremy Ruston

Ed,

It would be interesting to see the sum/max error without the fix for Basic 4.32.

Dave
by hoglet
Sat Jun 16, 2018 12:55 pm
Forum: for sale / freebies
Topic: Moving House - Items to go
Replies: 21
Views: 604

Re: Moving House - Items to go

PM sent...
by hoglet
Fri Jun 15, 2018 3:27 pm
Forum: hardware
Topic: RGB to HDMI using a Pi Zero and a small CPLD
Replies: 97
Views: 4985

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

To late to add optional scanline generator features I wonder. e.g. Not all all.... All you need to do is comment out this line: https://github.com/hoglet67/RGBtoHDMI/blob/0db17454599bea046c7e65bc1d6ad7a449088b1a/src/rgb_to_fb.S#L273 I'm sure we could make it a UI configurable option. I'll add this ...
by hoglet
Thu Jun 14, 2018 9:15 pm
Forum: software: other
Topic: Using BBC BASIC on a Homebrew Computer
Replies: 9
Views: 373

Re: Using BBC BASIC on a Homebrew Computer

roland wrote:
Thu Jun 14, 2018 8:37 pm
You can start by modifying the Atom BBC MOS rom as this contains most functions (api calls)!for running BBC Basic. I was looking for the source but I could not find it.
The source is here:
https://github.com/hoglet67/AtomSoftwar ... /ATMOS.asm

Dave
by hoglet
Wed Jun 13, 2018 6:41 pm
Forum: projects
Topic: 640x512 50 fps Bad Apple on a B... how?!
Replies: 28
Views: 750

Re: 640x512 50 fps Bad Apple on a B... how?!

cmorley wrote:
Wed Jun 13, 2018 6:37 pm
I could render 10s or 20s of video into an instruction stream say. I'll PM you a link.
Thanks, I might have a play with this tomorrow.
by hoglet
Wed Jun 13, 2018 6:31 pm
Forum: projects
Topic: 640x512 50 fps Bad Apple on a B... how?!
Replies: 28
Views: 750

Re: 640x512 50 fps Bad Apple on a B... how?!

There is DMA, but I'm not sure how it would help here. I think as a first step it would be worth coding this as a tight ARM-only loop, and see how it's affected by cache misses. We might just get away with it, and possibly there might be pre-fetching that would mask the true DRAM latency. This would...
by hoglet
Wed Jun 13, 2018 6:21 pm
Forum: hardware
Topic: Cheap web-modem for the beeb/master (and arc if ya like!)
Replies: 77
Views: 2727

Re: Cheap web-modem for the beeb/master (and arc if ya like!)

I'd be interested in the whole error log message please.
by hoglet
Wed Jun 13, 2018 5:59 pm
Forum: projects
Topic: 640x512 50 fps Bad Apple on a B... how?!
Replies: 28
Views: 750

Re: 640x512 50 fps Bad Apple on a B... how?!

No reason why it couldn't be made to run from a pi-tube direct i suppose. I don't think it would be easy though.... in fact I would go as far as saying it would be very tricky. The main difficulty is preventing the cache misses the Pi will experience from interrupting/crashing the instruction strea...
by hoglet
Wed Jun 13, 2018 4:50 pm
Forum: hardware
Topic: RGB to HDMI using a Pi Zero and a small CPLD
Replies: 97
Views: 4985

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

Having the option is good and we might be able to sneak a feature or two in when Hoglet isn't looking. One "feature" I was thinking about was a poor-mans Video NuLA, because the Pi's palette allows each of the eight colours to be redefined. I've also got a simple OSD-Menu system working, so that do...
by hoglet
Wed Jun 13, 2018 4:26 pm
Forum: hardware
Topic: RGB to HDMI using a Pi Zero and a small CPLD
Replies: 97
Views: 4985

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

HDMI will never look as good as a CRT. These machines were not designed with HD in mind, so will look awful when stretched on a big HDTV. There's not really any stretching going on, it uses the correct margins so the 4:3 aspect ratio is preserved. There are some screen shots earlier in the thread: ...
by hoglet
Wed Jun 13, 2018 12:45 pm
Forum: hardware
Topic: RGB to HDMI using a Pi Zero and a small CPLD
Replies: 97
Views: 4985

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

And the current prototype:
IMG_1323_small.JPG
Dave
by hoglet
Wed Jun 13, 2018 12:36 pm
Forum: hardware
Topic: RGB to HDMI using a Pi Zero and a small CPLD
Replies: 97
Views: 4985

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

Here's the final board design that has just been sent off to Seeed:
rgb-to-hdmi1.png
rgb-to-hdmi2.png
rgb-to-hdmi3.png
Total cost for ~10 boards was $15.28, including postage.

Now for the 3-4 week wait.

Dave
by hoglet
Tue Jun 12, 2018 6:24 pm
Forum: hardware
Topic: Meanwell PSU in a model B
Replies: 6
Views: 314

Re: Meanwell PSU in a model B

Edit: Sorry, I realize now you are asking about the Model B. I'll leave this info up anyway. Storrtech sells the Master ones on eBay: https://www.ebay.co.uk/itm/BBC-Master-Micro-Computer-Meanwell-PT-65A-Power-Supply-Brackets/113040838591 They are Simon's open source design, from this thread: https:/...
by hoglet
Tue Jun 12, 2018 6:23 am
Forum: hardware
Topic: Electron unstable/fails to boot when Plus 1 is connected
Replies: 21
Views: 1804

Re: Electron unstable/fails to boot when Plus 1 is connected

Glad you got it sorted.

Dave
by hoglet
Mon Jun 11, 2018 8:30 pm
Forum: acorn atom
Topic: ICE T65/Z80/6809
Replies: 634
Views: 42885

Re: ICE T65/Z80/6809

Great it's working for you. For anyone else who's interested: There are still a couple of level shifter boards available (£12) in Jason's shop: http://www.xeropage.co.uk/shop/index.php?id_product=16&controller=product And the "eepizza" boards are still available ($31) on eBay: https://www.ebay.com/i...
by hoglet
Mon Jun 11, 2018 5:12 pm
Forum: hardware
Topic: Electron unstable/fails to boot when Plus 1 is connected
Replies: 21
Views: 1804

Re: Electron unstable/fails to boot when Plus 1 is connected

I'm guessing a faulty IC, because a short to anything actually driven should pull it all the way down to ground, I would imagine. Pity I don't have any 14-pin sockets to play with! Guess it's desoldering time... Usually with this sort of issue, there is a low resistance path to ground inside the fa...
by hoglet
Mon Jun 11, 2018 2:09 pm
Forum: hardware
Topic: Open Source Logic Analyzer Experiments
Replies: 147
Views: 9481

Re: Open Source Logic Analyzer Experiments

I am using sigrok PulseView on 64 bit Windows 10 and have copied your python 6502 files into a new directory mos6502 under C:\Program Files (x86)\sigrok\PulseView\share\decoders but when I run Pulseview it does not pick up your analyser. I have also tried copying it to C:\Program Files (x86)\sigrok...
by hoglet
Mon Jun 11, 2018 5:31 am
Forum: acorn atom
Topic: Atom 2k18 ?
Replies: 19
Views: 500

Re: Atom 2k18 ?

Can the video and audio signals that are now routed with a separate cable from the top of the Godil also be routed via the header pins? Yes the can. The only reason for using those pins on the GODIL is it avoids passing the VGA video signal through level shifters, which greatly affected the quality...
by hoglet
Wed Jun 06, 2018 7:29 am
Forum: emulators
Topic: MAME: Speech
Replies: 17
Views: 855

Re: MAME: Speech

(Snap!)

It's a 74LS629, data sheet is here:
http://www.ti.com/lit/ds/symlink/sn54ls628.pdf
by hoglet
Wed Jun 06, 2018 6:41 am
Forum: emulators
Topic: Video Timing
Replies: 58
Views: 1810

Re: Video Timing

It would be very handy to have a minimal test case for this, then I'll try and fix it in BeebFPGA (which I think probably also has the issue).

Is there are conclusion as to what "additional" behaviour actually needs to be implemented to match the real 6845?

(I've slightly lost the plot)

Dave
by hoglet
Tue Jun 05, 2018 6:38 pm
Forum: off-topic
Topic: Microsoft to buy Github
Replies: 30
Views: 521

Re: Microsoft to buy Github

Back to the Github purchase... One thing to note is MS gets to control github through this purchase, but not git itself. So it's not going to affect the use of git as a local revision control system. There are many alternative places (git hosting services) you can use to share projects: GitLab, BitB...
by hoglet
Tue Jun 05, 2018 1:09 pm
Forum: hardware
Topic: RGB to HDMI using a Pi Zero and a small CPLD
Replies: 97
Views: 4985

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

I've had a think about Dominic's suggestion (adding support for programming from the Pi). I agree this would be a nice feature to have, but I'm inclined not to do add this for now, for a couple of reasons: 1. Trying to find space for 4 links plus the associated routing is painful 2. I don't really h...
by hoglet
Tue Jun 05, 2018 11:47 am
Forum: acorn atom
Topic: Atom 2k18 ?
Replies: 19
Views: 500

Re: Atom 2k18 ?

Are you thinking then that this would be incremental changes to the current design? I was wondering if it would be worth going for a 3.3V only design. You could then dispense with level shifers and use a £20-£30 Spartan 6 FPGA module to: - replace the GODIL - replace the CPLDs - replace the 244/245s...
by hoglet
Tue Jun 05, 2018 11:14 am
Forum: hardware
Topic: Open Source Logic Analyzer Experiments
Replies: 147
Views: 9481

Re: Open Source Logic Analyzer Experiments

I was a bit late to the party on this one. With regards to the work on the decoder for sigrok. I might have missed it but I am not sure I can see anything as to why it was not fast enough in Python. What I mean is if the Z80 cpu could be decoded why was the 6502 so much of an issue. Or was it jsut ...
by hoglet
Mon Jun 04, 2018 9:44 pm
Forum: hardware
Topic: RGB to HDMI using a Pi Zero and a small CPLD
Replies: 97
Views: 4985

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

Hi Guys, My third attempt at a PCB for this has been more successful - I've managed to reduce the form factor to the size of the Pi Zero: rgbtohdmi1.png rgbtohdmi2.png rgbtohdmi3.png The two upward pointing connectors are for debugging, and won't need to be fitted in the final system. This is using ...
by hoglet
Mon Jun 04, 2018 6:33 am
Forum: hardware
Topic: RGB to HDMI using a Pi Zero and a small CPLD
Replies: 97
Views: 4985

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

You beat me to suggesting a Weston deinterlacer - but I suspect the grunt required may put it out of reach? I don't think there is any way we will be able to implement any kind of advanced deinterlacing in software on the ARM. There just isn't the spare time, or the spare memory bandwidth. I think ...
by hoglet
Sun Jun 03, 2018 5:23 pm
Forum: upcoming and recent events & exhibitions
Topic: ABUG SOUTH 1 to 3 June 2018 (Hampshire) BOOKING THREAD
Replies: 125
Views: 6156

Re: ABUG SOUTH 1 to 3 June 2018 (Hampshire) BOOKING THREAD

Back in sunny Bristol now. I had a great weekend and it was nice that things were able to start slightly earlier on the Friday. The venue was excellent, very spacious, great food, great beer and great company. A big thank you again to Robert for organising this, and to the venue for being so accommo...
by hoglet
Sun Jun 03, 2018 4:57 pm
Forum: hardware
Topic: A3000 ROM schematic
Replies: 4
Views: 180

Re: A3000 ROM schematic

This zip I think contains the A3000 schematics: http://chrisacorns.computinghistory.org.uk/docs/Acorn/Manuals/Acorn_A3000TRM_drawings.zip And here's the accompanying technical reference manual: http://chrisacorns.computinghistory.org.uk/docs/Acorn/Manuals/Acorn_A3000TRM.pdf There is also the service...
by hoglet
Fri Jun 01, 2018 1:46 pm
Forum: upcoming and recent events & exhibitions
Topic: ABUG SOUTH 1 to 3 June 2018 (Hampshire) BOOKING THREAD
Replies: 125
Views: 6156

Re: ABUG SOUTH 1 to 3 June 2018 (Hampshire) BOOKING THREAD

I wonder if someone who has not left yet could bring along a 9-pin Atari style Joystick (switched)

I forgot to pack mine #-o

Many thanks and a Beer will be waiting!
by hoglet
Fri Jun 01, 2018 10:23 am
Forum: upcoming and recent events & exhibitions
Topic: ABUG SOUTH 1 to 3 June 2018 (Hampshire) BOOKING THREAD
Replies: 125
Views: 6156

Re: ABUG SOUTH 1 to 3 June 2018 (Hampshire) BOOKING THREAD

Google hangouts is not bad, then other parties can join in as well, if there is any interest.