Search found 7491 matches

by hoglet
Tue Oct 16, 2018 12:26 pm
Forum: hardware
Topic: BBD B+ Issues..please help
Replies: 19
Views: 458

Re: BBD B+ Issues..please help

nama wrote:
Tue Oct 16, 2018 8:49 am
I hooked up my logic analyser to IC30 and I can see the following data on the outputs:
Out of interest, what logic analyser do you have?
by hoglet
Tue Oct 16, 2018 10:52 am
Forum: hardware
Topic: Pi-based Co-Pro on the cheap - 100MHz 6502 for £10? (now 274MHz)
Replies: 1096
Views: 98282

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

Ian, I've been testing out the 80286 co pro and it crashes when trying to boot my existing hard drive installation of DOS Plus 1.2 which works OK on a real 80186 co-pro with 512K: I've just pushed a commit to the egg-eater-dev branch that should fix this. It sets the default memory value to 896KB. Y...
by hoglet
Tue Oct 16, 2018 6:57 am
Forum: hardware
Topic: Pi-based Co-Pro on the cheap - 100MHz 6502 for £10? (now 274MHz)
Replies: 1096
Views: 98282

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

I've been testing out the 80286 co pro and it crashes when trying to boot my existing hard drive installation of DOS Plus 1.2 which works OK on a real 80186 co-pro with 512K. This is actually an issue I investigated at ABUG in June. DOS 1.2 requires the amount of memory to be an integer multiple of...
by hoglet
Tue Oct 16, 2018 6:49 am
Forum: hardware
Topic: RGB to HDMI using a Pi Zero and a small CPLD
Replies: 331
Views: 12218

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

I had assumed you were trying to keep a lock by effectively doing a software PLL continually varying the HDMI clock to keep the vsyncs aligned. In theory that would stop tearing and might not require any buffering at all, eliminating the lag. Yes, this was a first step on the way to that goal, show...
by hoglet
Mon Oct 15, 2018 9:24 pm
Forum: hardware
Topic: RGB to HDMI using a Pi Zero and a small CPLD
Replies: 331
Views: 12218

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

Also as mentioned above, the vsync / hdmi freq. optimisation doesn't seem to be working for me as the red bar is always moving. The error is shown as 301ppm beeb slower than pi. It was quite experimental, and I didn't get much feedback. It's quite possible there are bugs. On my system I get 439ppm ...
by hoglet
Mon Oct 15, 2018 9:01 pm
Forum: hardware
Topic: RGB to HDMI using a Pi Zero and a small CPLD
Replies: 331
Views: 12218

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

Doesn't seem that necessary, you had the right solution and timing but just missed the inverted glitches. OK, lets go with a fixed value of 3, to give a small amount of extra margin. I'll test this with BigEd's Master (hopefully Wednesday) and then merge this into Master. On the other point, I don'...
by hoglet
Mon Oct 15, 2018 8:38 pm
Forum: hardware
Topic: Pi-based Co-Pro on the cheap - 100MHz 6502 for £10? (now 274MHz)
Replies: 1096
Views: 98282

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

1. I edited the config.txt file to comment out the kernel lines for RPi2 and RPi3 as I am using RPiZero. Is that even necessary? No, they are ignored. 2. Is it possible to emulate the 65C102 internal co-processor (with the same start up message)? I think the only difference is the startup message. ...
by hoglet
Mon Oct 15, 2018 8:02 pm
Forum: hardware
Topic: Raspberry Pi to 1MHz bus interface
Replies: 17
Views: 319

Re: Raspberry Pi to 1MHz bus interface

dp11 wrote:
Mon Oct 15, 2018 7:08 pm
It doesn't do anything yet. But it should be possible to emulate 1MHz bus devices in the Pizero.
This, of course, is left as an exercise for the interested reader. :lol:
by hoglet
Mon Oct 15, 2018 7:43 pm
Forum: hardware
Topic: RGB to HDMI using a Pi Zero and a small CPLD
Replies: 331
Views: 12218

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

Do you want me to try N=1 & 2 to determine the safety margin? Why not.... RGBtoHDMI.zip I wonder if it's worth making this software configurable from the Pi. There might just be the space to do that for up to n=7. This would cost 3 extra registers in the CPLD. Edit: Yup, just..... Function Mcells F...
by hoglet
Mon Oct 15, 2018 5:13 pm
Forum: hardware
Topic: RGB to HDMI using a Pi Zero and a small CPLD
Replies: 331
Views: 12218

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

Would you like to try builds with smaller value of N, say N=7 and N=3? Yes. Here you go: N=15, N=7 and N=3 to try: RGBtoHDMI.zip Other intermediate values would be possible. b) It's needed to support Tricky's smooth horizontal scrolling, which varies the sync pulse width (in the same way a CRT woul...
by hoglet
Mon Oct 15, 2018 4:51 pm
Forum: hardware
Topic: RGB to HDMI using a Pi Zero and a small CPLD
Replies: 331
Views: 12218

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

Good to hear that helped. Are you triggering off the falling or rising edge of the sync pulse? Initially I was triggering on the rising edge. But then switched to the falling edge, based on advice from others that: a) It was the correct thing to do b) It's needed to support Tricky's smooth horizonta...
by hoglet
Mon Oct 15, 2018 4:03 pm
Forum: hardware
Topic: RGB to HDMI using a Pi Zero and a small CPLD
Replies: 331
Views: 12218

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

Ian, Here's another version to try.... RGBtoHDMI.zip It may not be the final version, and indeed it may not even work! I have tested it on my Master, but as it doesn't have any glitches that's not very conclusive. In this version, de-glitching is applied to both csync=0 and csync=1 states. A change ...
by hoglet
Mon Oct 15, 2018 2:22 pm
Forum: hardware
Topic: RGB to HDMI using a Pi Zero and a small CPLD
Replies: 331
Views: 12218

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

I noticed there were inverted glitches in the sync signal itself, are you filtering those? Ah no, those won't currently be filtered. I don't think we saw those on Ed's Master. Let me have another think, but we are very short of registers so this may not be possible. It does seem strange how this is...
by hoglet
Mon Oct 15, 2018 10:26 am
Forum: hardware
Topic: RGB to HDMI using a Pi Zero and a small CPLD
Replies: 331
Views: 12218

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

scaling_kernel = 8 Gosh, that certainly makes an improvement in Modes 0..6. In Mode 7 I think it's subjective whether it's better or not. Anyway, onto the subject of de-glitching CSYNC. I've re-worked the de-glitching logic to use a 4-bit counter, so it should suppress CSYNC glitches of up to ~150n...
by hoglet
Mon Oct 15, 2018 8:03 am
Forum: hardware
Topic: RGB to HDMI using a Pi Zero and a small CPLD
Replies: 331
Views: 12218

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

Ian, Those glitches are similar to what we saw on BigEd's Master - only a bit more aggressive! What I will do this morning is see if I can squeeze a few more registers into the CPLD to make the glitch detection more robust. If this works, it may be better then the capacitor, as you really want a wel...
by hoglet
Sun Oct 14, 2018 9:47 pm
Forum: hardware
Topic: RGB to HDMI using a Pi Zero and a small CPLD
Replies: 331
Views: 12218

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

I agree, I put a 1nF capacitor from the sync line to ground and that got rid of it so it's likely HF noise on the sync line. Do you have a scope? If so, what model is it? It would be great if you could capture a trace of the glitch (without the 1nF capacitor). This is the current VHDL for glitch su...
by hoglet
Sun Oct 14, 2018 9:34 pm
Forum: hardware
Topic: RGB to HDMI using a Pi Zero and a small CPLD
Replies: 331
Views: 12218

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

There are some pictures of the CSYNC noise we captured on BigEd's Master in this post:
viewtopic.php?f=3&t=13973&p=207057&hili ... se#p207057

The glitches were ~10ns wide, so you might struggle to see them depending on your scope bandwidth.
by hoglet
Sun Oct 14, 2018 9:31 pm
Forum: hardware
Topic: RGB to HDMI using a Pi Zero and a small CPLD
Replies: 331
Views: 12218

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

Is it OK to disconnect the +5v and power it from a standard PI supply? I don't see why not, but it's not something I've tried myself. The reason being you would then need to be very careful about power supply sequencing, i.e. don't ever have the Beeb on and the Pi off, otherwise you risk damaging t...
by hoglet
Sun Oct 14, 2018 8:18 pm
Forum: hardware
Topic: RGB to HDMI using a Pi Zero and a small CPLD
Replies: 331
Views: 12218

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

This is on a Master 128. Hmmm, not seen this before. A few questions... Do you see this in all screen modes? Is this using a Pi Zero or a Pi Zero W? Is this with your own kernel, or with the standard distribution? How long is your cable? Do you have a different machine you could try it on? I assume...
by hoglet
Sun Oct 14, 2018 7:27 pm
Forum: hardware
Topic: RGB to HDMI using a Pi Zero and a small CPLD
Replies: 331
Views: 12218

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

Programming the RGBtoHDMI CPLD

Content moved to the wiki:
https://github.com/hoglet67/RGBtoHDMI/w ... rogramming
by hoglet
Sun Oct 14, 2018 6:53 pm
Forum: hardware
Topic: RGB to HDMI using a Pi Zero and a small CPLD
Replies: 331
Views: 12218

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

IanB wrote:
Sun Oct 14, 2018 6:34 pm
Ok I've installed that
Can you find/launch a program called "impact" without it crashing?

Do you actually have the programming cable now?

In the next post, I'll write down the steps you need to follow. It will take me a few minutes to do this...

Dave
by hoglet
Sun Oct 14, 2018 5:08 pm
Forum: hardware
Topic: RGB to HDMI using a Pi Zero and a small CPLD
Replies: 331
Views: 12218

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

No, I'm not sure what version to download You are in for a treat then..... the Xilinx tools, especially on Windows, are a complete nightmare. Some basics: - you need ISE 14.7, not Vivado (which is for more recent devices) - the recent ISE 14.7 Windows 10 release only supports Spartan 6 devices, not...
by hoglet
Sun Oct 14, 2018 3:50 pm
Forum: hardware
Topic: RGB to HDMI using a Pi Zero and a small CPLD
Replies: 331
Views: 12218

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

IanB wrote:
Sun Oct 14, 2018 3:36 pm
I've built up my boards and managed to get the Pi software to build using the tutorial from the pitubedirect wiki but a tutorial on how to build and program the Xilinx CPLD would be useful.
Do you have the Xilinx tools already installed?

What OS are you using?

Dave
by hoglet
Sun Oct 14, 2018 2:34 pm
Forum: hardware
Topic: Raspberry Pi to 1MHz bus interface
Replies: 17
Views: 319

Re: Raspberry Pi to 1MHz bus interface

Put me down for one please.

Dave
by hoglet
Sun Oct 14, 2018 6:52 am
Forum: acorn atom
Topic: Atom on FPGA based retro-computers
Replies: 15
Views: 3241

Re: Atom on FPGA based retro-computers

Seems there is a MIST - MISTICA core for Atom /Electron here (VGA only). I believe this is just the Acorn Electron (incorrectly named the Atom Electron). There is no Atom stuff there at all. It makes use of my Acorn Electron FPGA core. https://github.com/Gehstock/Mist_FPGA/blob/master/Acorn%20-%20E...
by hoglet
Sat Oct 13, 2018 11:43 am
Forum: for sale / freebies
Topic: Agilent-HP54201A Oscilloscope Excellent Condition
Replies: 26
Views: 2676

Re: Agilent-HP54201A Oscilloscope Excellent Condition

Will have a think, but lots of times I have thought ‘that would be a useful feature to have!’. But off top of my head the ones most useful that I have needed. More memory depth (with segmentation), extra channels (okay maybe this one is nice to have). And a bigger screen, it is annoying with multip...
by hoglet
Sat Oct 13, 2018 10:57 am
Forum: for sale / freebies
Topic: Agilent-HP54201A Oscilloscope Excellent Condition
Replies: 26
Views: 2676

Re: Agilent-HP54201A Oscilloscope Excellent Condition

Elminster wrote:
Sat Oct 13, 2018 9:50 am
Trouble is I have out grown my 1102 now, it lacks many of the features that are standard on the new scopes.
Can you give some examples of features you would like (that you would actually use)?
by hoglet
Fri Oct 12, 2018 6:59 pm
Forum: hardware
Topic: Pi-based Co-Pro on the cheap - 100MHz 6502 for £10? (now 274MHz)
Replies: 1096
Views: 98282

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

How feasible would it be to reverse the host/co-pro communication, passing VDU calls (for example) from the host to the co-pro for display via the Pi's HDMI output? Has this already been done? We did have a go at this in an older version of PiTubeDirect, before the GPU was used for all the tube han...
by hoglet
Fri Oct 12, 2018 6:21 pm
Forum: hardware
Topic: Memory Card Reader
Replies: 29
Views: 562

Re: Memory Card Reader

I've noticed some oddities with MMFS though - when I first switch the Beeb on and try to access the card, there's quite a long wait. Sometimes it seems to get stuck completely. CTRL Break, then *DRECAT usually fixes this - the shift lock light seems to be used as an activity indicator, and when thi...
by hoglet
Wed Oct 10, 2018 12:36 pm
Forum: software: other
Topic: Music 500/5000 software/music
Replies: 45
Views: 760

Re: Music 500/5000 software/music

Coeus wrote:
Wed Oct 10, 2018 12:27 pm
It would be good to implement the M3000 in B-Em. I gather it is a second M5000 but at a different address. Anyone know what address?
The address is &5x, see here:
viewtopic.php?p=187735#p187735

Dave