Search found 611 matches

by IanB
Mon Apr 20, 2020 3:16 pm
Forum: 8-bit acorn hardware
Topic: RGB to HDMI using a Pi Zero and a small CPLD
Replies: 1239
Views: 98851

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

When first powered on the screen comes alive with the Blank CPLD detected message however the cursor to select the 3 bit firmware version is jumping around up and down. As others have said, the likely cause is shorts or bad connections around the Pi header pins 35,36,37 or the CPLD pins 38,39,40 or...
by IanB
Mon Apr 20, 2020 2:27 pm
Forum: 8-bit acorn hardware
Topic: Pi based Prisma 3 emulation connected via 1Mhz bus
Replies: 77
Views: 5786

Re: Pi based Prisma 3 emulation connected via 1Mhz bus

XL1 Crystal: The Prisma3 manual p.112 says the ACRTC operates at 7.5MHz, and the photo of the board at http://chrisacorns.computinghistory.org.uk/32bit_UpgradesH2Z/Millipede_Prisma3.html looks to have a 15MHz crystal which makes sense with a divider. When I saw Paul Emerton's Prisma 3+ I took some ...
by IanB
Sat Apr 18, 2020 1:06 am
Forum: 8-bit acorn hardware
Topic: Pi based Prisma 3 emulation connected via 1Mhz bus
Replies: 77
Views: 5786

Re: Pi based Prisma 3 emulation connected via 1Mhz bus

I now have zoom kinda working: Looking better! I'm only applying the zoom factor to the base screen, so am surprised the Joe character is also zoomed. Obviously also priority and transparency issues to look at too. Any suggestions on what I should look at? Don't know about the window zoom, seems li...
by IanB
Wed Apr 15, 2020 10:59 pm
Forum: 8-bit acorn hardware
Topic: Pi based Prisma 3 emulation connected via 1Mhz bus
Replies: 77
Views: 5786

Re: Pi based Prisma 3 emulation connected via 1Mhz bus

Is this later manual available? Not yet but I plan to scan it. I also have the supplemental manual that describes the Prisma 3+ which has 6MB of RAM and uses bank switching as well as the Archimedes extensions. I haven't been able to get SNOOKQUIZ to actually display anything, but I do see the vide...
by IanB
Mon Apr 13, 2020 5:06 pm
Forum: 8-bit acorn hardware
Topic: Pi based Prisma 3 emulation connected via 1Mhz bus
Replies: 77
Views: 5786

Re: Pi based Prisma 3 emulation connected via 1Mhz bus

Amazing! Can you confirm that the preset palettes 1 and 2 match my screenshots? Yes, that's correct. Note the 256xxxx files are actually 16 colour Prisma 2 files re-saved in 256 colour format so only use the first 16 entries of the palette. I have no idea what this game is supposed to look like, so ...
by IanB
Sat Apr 11, 2020 10:45 pm
Forum: 8-bit acorn hardware
Topic: ADFS 512 byte sector patch for SASI/SCSI drives
Replies: 54
Views: 6331

Re: ADFS 512 byte sector patch for SASI/SCSI drives

Okay. That's starting to get a bit more complicated! I don't have any cartridges, so would probably need to replace the entire ROM. A job for another day. Thanks for your assistance. I just took a closer look and the ADFS that was patched was version 2.03 from MOS 3.50 so in order for this to work ...
by IanB
Sat Apr 11, 2020 10:20 pm
Forum: 8-bit acorn hardware
Topic: ADFS 512 byte sector patch for SASI/SCSI drives
Replies: 54
Views: 6331

Re: ADFS 512 byte sector patch for SASI/SCSI drives

unplugged the original ADFS (bank 13), but I'm getting very strange results when I try to reset the Master. They both report ok when I do a *HELP. Do these ROMs work in SWRAM banks, or do I need to get them burned to ROM? Or is there anything else I need to be aware of? Thinking about it, I recall ...
by IanB
Sat Apr 11, 2020 9:22 pm
Forum: 8-bit acorn hardware
Topic: ADFS 512 byte sector patch for SASI/SCSI drives
Replies: 54
Views: 6331

Re: ADFS 512 byte sector patch for SASI/SCSI drives

Or is there anything else I need to be aware of? Not that I can recall, you could try the OSCSICODE instead of SCSICODEH (H for hacked about?). Unfortunately I don't have any way of testing it myself anymore but I don't recall any problems with it. Do you have any other ROMs like Econet installed? ...
by IanB
Sat Apr 11, 2020 8:11 pm
Forum: 8-bit acorn hardware
Topic: ADFS 512 byte sector patch for SASI/SCSI drives
Replies: 54
Views: 6331

Re: ADFS 512 byte sector patch for SASI/SCSI drives

Hi Ian, This patched ADFS would be very useful; even if just to help with diagnosing the issue. Noted that it only works on the Master 128. Is this a workspace issue? Do you know if it would be possible to get it running on a beeb with appropriate SWRam / Shadow RAM etc? Here is the patched ADFS in...
by IanB
Sat Apr 11, 2020 4:58 pm
Forum: 8-bit acorn hardware
Topic: ADFS 512 byte sector patch for SASI/SCSI drives
Replies: 54
Views: 6331

Re: ADFS 512 byte sector patch for SASI/SCSI drives

Folks, Sorry for dragging up an old thread here, but I'm struggling to format my ST32151n using my beeb. Sorry I can't help with the SCSI commands but if you can't solve it and get stuck with 512 byte sectors I have a 512 byte patched version of ADFS which we commissioned Mike Harrison to do for us...
by IanB
Fri Apr 10, 2020 10:21 pm
Forum: 8-bit acorn hardware
Topic: Pi based Prisma 3 emulation connected via 1Mhz bus
Replies: 77
Views: 5786

Re: Pi based Prisma 3 emulation connected via 1Mhz bus

Thanks, does this have the normal *CONFIGURE settings as described on p18 of the manual? I just ran those configs and got some minor changes including one config not documented in that manual (but is documented in my later manual) which is *CONFIGURE ZOOM 1 Prisma3-NVRAM_V2.zip For some reason zoom...
by IanB
Fri Apr 10, 2020 8:54 pm
Forum: 8-bit acorn hardware
Topic: Pi based Prisma 3 emulation connected via 1Mhz bus
Replies: 77
Views: 5786

Re: Pi based Prisma 3 emulation connected via 1Mhz bus

I'm getting to the point where I'd like the NVRAM contents to ensure the palettes are initialised correctly. Could this be read using the palette registers and written to a file? I wrote a simple BASIC program to read the NVRAM directly from the Prisma registers: [deleted] It seems to be mostly emp...
by IanB
Fri Apr 10, 2020 5:45 pm
Forum: 8-bit acorn hardware
Topic: Pi based Prisma 3 emulation connected via 1Mhz bus
Replies: 77
Views: 5786

Re: Pi based Prisma 3 emulation connected via 1Mhz bus

Here's my first attempt at displaying a Prisma image on the 1MHz Bus Frame Buffer: Nice. The metadata says the size is 0x05FE x 0x047A which is 1534 x 1146. But the resolution is actually 768 x 574, as you stated eariler in this thread. It looks like the values stored in the header are in fact 2*(x...
by IanB
Thu Apr 09, 2020 11:39 pm
Forum: 8-bit acorn hardware
Topic: Pi based Prisma 3 emulation connected via 1Mhz bus
Replies: 77
Views: 5786

Re: Pi based Prisma 3 emulation connected via 1Mhz bus

hoglet wrote:
Thu Apr 09, 2020 10:22 pm
Is the ADFS disk containing example pictures (like the above train) available to download somewhere?
Pernod wrote:
Thu Apr 09, 2020 10:48 pm
It's a 66MB SCSI HDD image, I'll let Ian handle any distribution.
Here's the updated HD image with the missing HAFOC pics:
scsi0.zip
(1.22 MiB) Downloaded 22 times
by IanB
Thu Apr 09, 2020 4:17 pm
Forum: 8-bit acorn hardware
Topic: RGB to HDMI using a Pi Zero and a small CPLD
Replies: 1239
Views: 98851

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

BeebMaster wrote:
Thu Apr 09, 2020 3:47 pm
Is it a "slow" card causing it then?
I assume it must be, the Pi is behaving like the HDMI lead is not connected on the first bootup. HDMI setup is controlled by the Pi firmware so there isn't much that can be done about it other than reboot to work around the problem.
by IanB
Thu Apr 09, 2020 3:05 pm
Forum: 8-bit acorn hardware
Topic: Pi based Prisma 3 emulation connected via 1Mhz bus
Replies: 77
Views: 5786

Re: Pi based Prisma 3 emulation connected via 1Mhz bus

Ignore the palette for now, that'll be worked on when I have a recognisable image. Great progress, this is what that image should look like: TRAIN6.jpg BTW I think I missed out the image files for HAVOC which is why you got that error message above. When you've got loading working I'll do an update...
by IanB
Thu Apr 09, 2020 2:54 pm
Forum: 8-bit acorn hardware
Topic: RGB to HDMI using a Pi Zero and a small CPLD
Replies: 1239
Views: 98851

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

Ahhh...I just tried a completely different card, a 128MB (yes, MB!) one and it's the same, no picture until reset. The Kingston one is a class 4 and I think the 128MB one even predates that system, so it probably is something to do with older or slower cards. I think I manage to reproduce the probl...
by IanB
Wed Apr 08, 2020 10:19 pm
Forum: 8-bit acorn hardware
Topic: RGB to HDMI using a Pi Zero and a small CPLD
Replies: 1239
Views: 98851

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

BeebMaster wrote:
Wed Apr 08, 2020 8:19 pm
Sadly that hasn't helped after both updates. I think we'll just have to put it down to a rogue card.
Can you post the log before and after pressing reset and also your custom profile.
by IanB
Wed Apr 08, 2020 5:04 pm
Forum: 8-bit acorn hardware
Topic: RGB to HDMI using a Pi Zero and a small CPLD
Replies: 1239
Views: 98851

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

If it helps this is the debug output with Fill 4:3 scaling (no picture): Wed,08 Apr 2020.14:42:05.435663 Initialised Framebuffer Wed,08 Apr 2020.14:42:05.437121 Size: 1296x288 Wed,08 Apr 2020.14:42:05.438699 Pitch: 656 bytes Again that doesn't look the right size for the resolution and profile. Can...
by IanB
Tue Apr 07, 2020 8:56 pm
Forum: 8-bit acorn hardware
Topic: Pi based Prisma 3 emulation connected via 1Mhz bus
Replies: 77
Views: 5786

Re: Pi based Prisma 3 emulation connected via 1Mhz bus

That should be very helpful. I can only assume it's polling the Status register for the Write FIFO flags to determine when to write data. I found the code and it looks quite straightforward: // dma write 12020 JSR s1acrtcmove 12030 JSR memstart 12040 JSR dmawrite 12050.putscrn 12060 LDA (rC),Y 1207...
by IanB
Tue Apr 07, 2020 7:37 pm
Forum: 8-bit acorn hardware
Topic: Pi based Prisma 3 emulation connected via 1Mhz bus
Replies: 77
Views: 5786

Re: Pi based Prisma 3 emulation connected via 1Mhz bus

The BBC interface uses the HD63484 in 8bit mode only and the datasheet says that DMA can be used without a DMAC and be handled under software control, but isn't clear on how this should be implemented. Yes, that's correct, it's simply I/O polled, no DMA required. You setup the 20 bit memory address...
by IanB
Tue Apr 07, 2020 5:10 pm
Forum: 8-bit acorn hardware
Topic: RGB to HDMI using a Pi Zero and a small CPLD
Replies: 1239
Views: 98851

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

Is it worth running off a couple of the latest analogue boards or are they likely to change a lot? The issue 3 analog board is pretty stable now and not likely to change much if at all. Using the 6 way IDC header on the end of the PCB works really well. In addition to the 3 bit TTL buffer board whi...
by IanB
Tue Apr 07, 2020 4:57 pm
Forum: 8-bit acorn hardware
Topic: Pi based Prisma 3 emulation connected via 1Mhz bus
Replies: 77
Views: 5786

Re: Pi based Prisma 3 emulation connected via 1Mhz bus

Pernod wrote:
Sun Apr 05, 2020 2:58 am
Showing signs of life, but really need to get DMA implemented to be able to load pics ...
Looks good so far
by IanB
Sat Apr 04, 2020 2:36 pm
Forum: 8-bit acorn hardware
Topic: RGB to HDMI using a Pi Zero and a small CPLD
Replies: 1239
Views: 98851

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

PS I was a little confused about the genloc/buffers, unless single buffered=0 buffers, why would 1 be less lag than 0?. Single buffered means that one frame buffer is in use which is the buffer that the GPU uses to display the video. This buffer is simultaneously written to by the PI capture softwa...
by IanB
Fri Apr 03, 2020 9:22 pm
Forum: 8-bit acorn hardware
Topic: RGB to HDMI using a Pi Zero and a small CPLD
Replies: 1239
Views: 98851

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

Neither work with one of my TVs and I havnt tried the other. Try 60Hz modes if the 50Hz ones don't work. On the new one with nearly every button press the elgato looses sync and I have to wait 10+ seconds for it to sync again. Try changing the Genlock speed in the settings menu to the slowest setti...
by IanB
Wed Apr 01, 2020 6:51 pm
Forum: 8-bit acorn hardware
Topic: RGB to HDMI using a Pi Zero and a small CPLD
Replies: 1239
Views: 98851

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

Still not got model numbers, but my old RGB2HDMI doesn't seem to be working, so maybe there is an issue with the three HDMI cables that I have tried! Are you using a mini HDMI to HDMI cable or an adapter with a normal cable? I have found some adapters with some cable and monitor combinations result...
by IanB
Tue Mar 31, 2020 3:45 pm
Forum: 8-bit acorn hardware
Topic: RGB to HDMI using a Pi Zero and a small CPLD
Replies: 1239
Views: 98851

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

I still can't get anything that matches the DVD screen captures in Mode 7 that I've been using for years. You won't because the Mode 7 pixels aren't square and the current screengrab code only handles square pixels. You will either get something that is a bit too narrow (Uneven scaling) or a bit to...
by IanB
Tue Mar 31, 2020 2:38 pm
Forum: 8-bit acorn hardware
Topic: RGB to HDMI using a Pi Zero and a small CPLD
Replies: 1239
Views: 98851

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

I'm agog - what software change brings this troublesome SD card back into play? It was a total kludge. From previous logs, Beebmaster was getting: Sat,21 Mar 2020.20:29:56.595247 Initialised Framebuffer Sat,21 Mar 2020.20:29:56.595379 Size: 1920x8192 Sat,21 Mar 2020.20:29:56.595425 Pitch: 1920 byte...
by IanB
Mon Mar 30, 2020 9:30 pm
Forum: 8-bit acorn hardware
Topic: RGB to HDMI using a Pi Zero and a small CPLD
Replies: 1239
Views: 98851

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

Also I've noticed that because I use *TV 255 to fix the picture on my Sony Trinitron TV of universal ABug acclaim (well, 3 different people said they liked it) the bottom pixel row is missed off the screen: You would get a few pixels clipped with *TV255 on a 1080p screen as it won't fit, however if...
by IanB
Fri Mar 27, 2020 3:01 pm
Forum: 8-bit acorn hardware
Topic: RGB to HDMI using a Pi Zero and a small CPLD
Replies: 1239
Views: 98851

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

I'm using the BBC Micro v21-v23 profile, and I set H Offset to 100 (I think it was set at 126 by default). If the offered profiles have versions, you are still stuck in legacy mode with a very old CPLD version. The IntegraB board doesn't touch the video hardware. I think it's the IBOS (IntegraB OS)...

Go to advanced search