Search found 401 matches

by IanB
Thu Nov 07, 2019 7:35 pm
Forum: hardware
Topic: RGB to HDMI using a Pi Zero and a small CPLD
Replies: 800
Views: 44202

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

-B- wrote:
Thu Nov 07, 2019 8:14 am
Ah, you beat me to it. I am using your ZX81 circuit with the old version of the board...
That's very neat, I assume it works OK? (I was concerned that the extra heat inside the PI case might make the threshold adjustments a bit unstable.)
by IanB
Thu Nov 07, 2019 7:17 pm
Forum: hardware
Topic: RGB to HDMI using a Pi Zero and a small CPLD
Replies: 800
Views: 44202

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

I fitted 330R termination resistors, and it can just about descriminate the three level RGB signals, due to the differeing thresholds of the 74LS08 buffer and the CPLD. That's a clever trick although it may not be reliably repeatable. Am I right in thinking that as well as plugging in to the 2x5 wa...
by IanB
Thu Nov 07, 2019 3:16 am
Forum: hardware
Topic: RGB to HDMI using a Pi Zero and a small CPLD
Replies: 800
Views: 44202

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

While I was waiting for the PCBs, I did some preliminary design on an analog interface add-on which should increase the number of old computers supported. The design uses some fast comparators and D to A converters to set the thresholds from the menus instead of the potentiometers used in my origina...
by IanB
Wed Nov 06, 2019 11:04 pm
Forum: hardware
Topic: PS/2 keyboard & mouse to Archimedes adapter MK II
Replies: 33
Views: 5201

Re: PS/2 keyboard & mouse to Archimedes adapter MK II

So both error lights come on when pressing record. The mouse and keyboard still don't respond after the recording has finished. (I can do a reset with windows key + break, which I don't think I could do before). Is it possible to disable to timeout?, the standard arc keyboard appears to handle inte...
by IanB
Wed Nov 06, 2019 9:21 pm
Forum: hardware
Topic: PS/2 keyboard & mouse to Archimedes adapter MK II
Replies: 33
Views: 5201

Re: PS/2 keyboard & mouse to Archimedes adapter MK II

It does look like interrupts are disabled (makes sense, as they are probably polling the A/D converter). With an original Arc keyboard the caps lock doesn't respond during recording. I found a possible problem where the protocol error flag wasn't being cleared on a restart which would cause an infi...
by IanB
Wed Nov 06, 2019 8:54 pm
Forum: hardware
Topic: PS/2 keyboard & mouse to Archimedes adapter MK II
Replies: 33
Views: 5201

Re: PS/2 keyboard & mouse to Archimedes adapter MK II

On a real Arc keyboard the mouse freezes during recording, but then moves again after the recording has finished. With the PS/2 adapter, when you click record, both error lights come on, and the mouse and keyboard won't work again until after a power cycle. Two leds means an error occurred with the...
by IanB
Wed Nov 06, 2019 7:11 pm
Forum: hardware
Topic: RGB to HDMI using a Pi Zero and a small CPLD
Replies: 800
Views: 44202

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

Nice work! but it's only for Elk and PC, or it works with Micros and Masters too? Yes BBC, Master 128 and most Electrons. (I've just edited the post to make that a bit clearer) There may be an issue with some early Electrons as I had to remove the buffer Dave used to get his early Electron working ...
by IanB
Wed Nov 06, 2019 6:44 pm
Forum: hardware
Topic: RGB to HDMI using a Pi Zero and a small CPLD
Replies: 800
Views: 44202

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

I received my new six bit PCBs from JLC today: boards.jpg I built one up and it worked first time including self programming of the CPLD by the PI so no programmer was needed: (Shown with a PC lead for MDA, CGA and EGA) assembled.jpg This shows the underside with the new IDC header to mount the cabl...
by IanB
Sun Nov 03, 2019 9:44 pm
Forum: hardware
Topic: PS/2 keyboard & mouse to Archimedes adapter MK II
Replies: 33
Views: 5201

Re: PS/2 keyboard & mouse to Archimedes adapter MK II

IanS wrote:
Sat Nov 02, 2019 11:55 pm
Not a show-stopper, but was supprised that with only a mouse connected the mouse buttons don't work, it appears to need a keyboard connected to allow any button presses (keyboard or mouse) to register.
Here's V0.17 with the mouse button bug fixed:
arc2ps2-v0-17.zip
(12.65 KiB) Downloaded 3 times
by IanB
Sun Nov 03, 2019 2:21 am
Forum: hardware
Topic: PS/2 keyboard & mouse to Archimedes adapter MK II
Replies: 33
Views: 5201

Re: PS/2 keyboard & mouse to Archimedes adapter MK II

Pin 4 appears to have a fairly high input resistance. I tried adding a 4K7 pull-up, with a jumper to pull it low, but with just the resistor, the voltage on pin4 was only about 1.5V, which wasn't enough to register it as high. The prototyping board I used above had a 10K pullup on that line and I n...
by IanB
Sat Nov 02, 2019 10:08 pm
Forum: hardware
Topic: PS/2 keyboard & mouse to Archimedes adapter MK II
Replies: 33
Views: 5201

Re: PS/2 keyboard & mouse to Archimedes adapter MK II

I'm not sure what the Reset link for the mode selection on the original PCB does to pin 4. Is it pulled high/low or open circuit. Does it need pulling high or low to change mode? The "reset" line is just used as a normal input port in this design, actual power on reset relies on internal timeconsta...
by IanB
Fri Oct 18, 2019 9:42 pm
Forum: hardware
Topic: RGB to HDMI using a Pi Zero and a small CPLD
Replies: 800
Views: 44202

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

Well I finally learned how to use Kicad and this is my first attempt at a 6 bit version of the PCB using a 5x2 IDC connector. rgb-to-hdmi.jpg The signals on the header are 2 bits each for RGB, Sync, Vsync, +5v & 0v. All 8 inputs are now pulled low by resistor packs so there will be no floating input...
by IanB
Sat Sep 28, 2019 11:15 pm
Forum: hardware
Topic: CF Card Issues
Replies: 5
Views: 323

Re: CF Card Issues

It works fine, but I can't seem to get the card to be recognised on ADFS explorer. It has a 4gb card in it, it is recognised as just a single 4gb partition. Any idea how I can back it up and/or add files to it from any machine. It isn't recognised on mac or windows. First thing is to make sure you ...
by IanB
Tue Aug 27, 2019 11:41 am
Forum: emulators
Topic: MAME: Video Digitisers
Replies: 13
Views: 767

Re: MAME: Video Digitisers

For the Hand Scanner I think I'll need to know what's inside the interface. Anyone have one? I have one but it's a PLD and I don't have the equations. The only info I have is the technical description of the 1Mhz bus location usage posted above so you might be able to use that to derive the functio...
by IanB
Tue Aug 27, 2019 11:40 am
Forum: emulators
Topic: MAME: Video Digitisers
Replies: 13
Views: 767

Re: MAME: Video Digitisers

Pernod wrote:
Sun Aug 25, 2019 12:17 pm
I see the Digitiser board has a crystal, anyone know it's value and what it's used for?
The crystal is 4 Mhz and it is the "pixel clock" for the sampling position along a line so 256 ticks covers the 64uS of a full line
Pernod wrote:
Sun Aug 25, 2019 12:17 pm
I am very impressed with the results so far though 8)
Me too
by IanB
Mon Aug 12, 2019 9:40 pm
Forum: software
Topic: Lost RISC OS Econet, AUN and NFS software
Replies: 19
Views: 2126

Re: Lost RISC OS Econet, AUN and NFS software

I can get !Gateway running but it never passes any frames between Econet and Ethernet (I'm guessing due to the fact that the Ether3 is DCI4). The DCI4 version of !Gateway is now on ROOL in the bonus binaries collection: https://www.riscosopen.org/content/downloads/common Source is here: https://git...
by IanB
Mon Aug 12, 2019 9:26 pm
Forum: software: other
Topic: Wapping Editor printer driver
Replies: 20
Views: 631

Re: Wapping Editor printer driver

Wow, super early version. Only 1.30 is currently archived. I'm not sure if I ever archived all old versions of the code, I just found v1.10 and v0.85 but haven't looked in detail yet. Is the 64k ROM so fully packed that the extra features from the support rom image don't fit within the 64k? Yes, th...
by IanB
Sat Aug 10, 2019 5:07 pm
Forum: software: other
Topic: Wapping Editor printer driver
Replies: 20
Views: 631

Re: Wapping Editor printer driver

I can't find what version I'm running from Wapping Editor. This is what I get when I've started up. That looks like an early version, what shows up when you use *HELP? Do I need to run the Editor 1.3 version to use the 1.3 Support Rom? Yes, you need to update your EPROM to 1.30 Here's a copy of the...
by IanB
Sat Aug 10, 2019 3:31 pm
Forum: software: other
Topic: Wapping Editor printer driver
Replies: 20
Views: 631

Re: Wapping Editor printer driver

Hmmm, I'm getting the impression that Wapping Editor doesn't see the supporting rom after all. Or should the support rom been blown on an eprom instead of loading it in SWR socket 4? A message is displayed in the bottom right indicating the support rom is detected. This is what I get with the exten...
by IanB
Fri Aug 09, 2019 10:02 pm
Forum: hardware
Topic: Clwyd Technics Colour Palette enhancer
Replies: 10
Views: 1537

Re: Clwyd Technics Colour Palette enhancer

IanB, I don't suppose you have a schematic for your 1MHz bus version? Would I be correct in guessing it's a Chameleon controlled through its own 6522 addressed somewhere in FRED? This is the documentation in view format for the 1Mhz bus palette version which details the ROM functions and hardware: ...
by IanB
Fri Aug 09, 2019 6:29 pm
Forum: software: other
Topic: Wapping Editor printer driver
Replies: 20
Views: 631

Re: Wapping Editor printer driver

Version 1.3 says that ther should be a little menu appear where you can select different printing modes (draft, normal, High etc.) But I don't see the menu appear when I click the print button. (as the readme file explained) This is what's displayed on Wapping Editor 1.30 with Scanner Driver 1.31 (...
by IanB
Fri Jul 12, 2019 6:29 pm
Forum: hardware
Topic: RGB to HDMI using a Pi Zero and a small CPLD
Replies: 800
Views: 44202

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

Issue 3 - auto resolution seemingly picks wrong resolution Auto resolution is necessary to ensure that a picture is visible on the monitor on first startup but it isn't very useful for actually using it with a BBC / Electron or any other 50Hz based source. The Auto setting ensures that the Pi selec...
by IanB
Thu Jul 11, 2019 9:27 pm
Forum: hardware
Topic: RGB to HDMI using a Pi Zero and a small CPLD
Replies: 800
Views: 44202

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

That's expected. Even though your monitor's native resolution is 800x600, it likely supports 1280x720 over HDMI (so it could claim to be HD Ready). When set to Resolution=Auto, the Pi will pick the highest resolution. That seems to be the case here and it's rather annoying as you can't determine th...
by IanB
Thu Jul 11, 2019 8:53 pm
Forum: hardware
Topic: RGB to HDMI using a Pi Zero and a small CPLD
Replies: 800
Views: 44202

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

Ian, I believe its's an 800x600 native resoution monitor: Sorry I wrote my reply while the monitor info was being posted so missed it. So Integer scaling should give reasonable results, don't you agree? It should if it is actually 800x600 but not if it's 1024x 768 or 1280 x1024 when I would expect ...
by IanB
Thu Jul 11, 2019 8:13 pm
Forum: hardware
Topic: RGB to HDMI using a Pi Zero and a small CPLD
Replies: 800
Views: 44202

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

I had already done the screenshots, I just hand not uploaded them. I didn't have a colour border but I did use characters to set the border. That looks like a 1280x1024 monitor and you can't do full integer scaling (which is the default) with that resolution although there is a slightly later build...
by IanB
Fri Jun 14, 2019 12:03 am
Forum: hardware
Topic: RGB to HDMI using a Pi Zero and a small CPLD
Replies: 800
Views: 44202

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

I was asked in a PM if this adapter would work with a Spectrum so I did a bit of investigation. The original Spectrum only had multi level YUV internally so there is no simple way to get it working although a similar interface to the Atom board to convert YUV to TTL RGBI could be designed. However i...
by IanB
Thu Jun 06, 2019 10:29 am
Forum: hardware
Topic: RGB to HDMI using a Pi Zero and a small CPLD
Replies: 800
Views: 44202

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

marcusjambler wrote:
Thu Jun 06, 2019 7:42 am
Interested in a PCB if there are some [-o<
Looks like someone has listed their surplus ones on ebay:

https://www.ebay.co.uk/itm/PCB-for-the- ... 3516528081
by IanB
Wed Jun 05, 2019 11:31 pm
Forum: acorn atom and system
Topic: Atom Video to HDMI Adapter
Replies: 219
Views: 9682

Re: Atom Video to HDMI Adapter

Nice find... I didn't know these existed. There are some other types on eBay. I ended up using the 10cm version of this Micro SD card extension: https://www.ebay.co.uk/itm/TV-TF-To-Micro-SD-Card-Extension-Cable-Extender-Reader-For-Phone-GPS-10-46cm/192444801142 I managed to get it to fit reasonably...
by IanB
Thu May 30, 2019 11:06 pm
Forum: acorn atom and system
Topic: Atom Video to HDMI Adapter
Replies: 219
Views: 9682

Re: Atom Video to HDMI Adapter

Maybe a proper setting will remove the margins? I made some changes with the latest commits that do try to eliminate the black margins in many resolutions but unfortunately, you can't get a perfect result where you have both integer scaling and the border exactly filling the screen with a 1024x768 ...
by IanB
Mon May 27, 2019 12:17 am
Forum: archive submissions
Topic: Various Atom Documents
Replies: 4
Views: 938

Re: Various Atom Documents

In the Disk Pack document there is reference to SPOOL and EXEC utilities. Are these built in to Atom DOS? The strings SPOOL SHUT and EXEC are present in the Atom and System DOS ROMs so they look like built in features In the Expansions document is another reference to the ONLI ROM, which showed up ...