Search found 9302 matches

by hoglet
Thu Aug 13, 2020 7:02 pm
Forum: 8-bit acorn hardware
Topic: Kenda "The Professional" DMFS
Replies: 59
Views: 992

Re: Kenda "The Professional" DMFS

Good to see it working in MAME Nigel. I did manage to get the double density mode working, but it's incredibly slow, because the block size is 2048b (16 sectors), and all operations are single sector. It's so slow it's completely unusable! Over a minute to save a 1-line BASIC program. I created the ...
by hoglet
Thu Aug 13, 2020 3:39 pm
Forum: 8-bit acorn hardware
Topic: Kenda "The Professional" DMFS
Replies: 59
Views: 992

Re: Kenda "The Professional" DMFS

Your image is 200K which suggests 80 tracks. Is it supposed to be 80 track single sided or 40 track double sided? Sorry, it was generated using MMFS, which only deals with 200KB .ssd files. What you need to end up with is: - Side 0 - kenda.ssd - Side 2 - contents don't really matter, as long as it'...
by hoglet
Thu Aug 13, 2020 12:59 pm
Forum: 8-bit acorn hardware
Topic: Kenda "The Professional" DMFS
Replies: 59
Views: 992

Re: Kenda "The Professional" DMFS

Right, I think I've got it working.... :D I've managed to create a useable blank disk from a blank/formatted DFS disk. A double-sided, 80 track, single density DMFS disk has 401,408 bytes free, according to the documentation. This is 392 1K blocks, starting at track 3 on side 0. The key is to correc...
by hoglet
Thu Aug 13, 2020 7:05 am
Forum: 8-bit acorn hardware
Topic: Refurbishing a Torch Z80 Disc Pack
Replies: 7
Views: 193

Re: Refurbishing a Torch Z80 Disc Pack

You can get triple output versions of the Meanwell power supplies, for example: https://www.meanwell-web.com/en-gb/closed-frame-power-supplies/all-application/all-technology/5_-_1/ac-dc-triple-output-enclosed-power-supply-output-rt--65a?returnurl=%2fen-gb%2fclosed-frame-power-supplies%2fall-applicat...
by hoglet
Wed Aug 12, 2020 10:10 pm
Forum: 8-bit acorn hardware
Topic: Kenda "The Professional" DMFS
Replies: 59
Views: 992

Re: Kenda "The Professional" DMFS

It looks like the first thing DMFS does is to read track 0 sector 9 in single density, and save this at 0xB000. I think this contains additional info about the disk format. For example, bit 7 of byte 0x62 of this sector selects the density (0 = single, 1 = double). It's used here: 9156 : A9 08 : LDA...
by hoglet
Wed Aug 12, 2020 9:36 pm
Forum: 8-bit acorn hardware
Topic: Kenda "The Professional" DMFS
Replies: 59
Views: 992

Re: Kenda "The Professional" DMFS

This is what I see with a single-density Acorn Z80 CP/M disk:
capture8.png
It seems the single density format is a fairly close match.
http://mdfs.net/Docs/Comp/Disk/Format/AcornCPM

Dave
by hoglet
Wed Aug 12, 2020 9:17 pm
Forum: 8-bit acorn hardware
Topic: Kenda "The Professional" DMFS
Replies: 59
Views: 992

Re: Kenda "The Professional" DMFS

What did you do to get it to set bit 7 of the latch? I've switched to a freshly formatted DFS disk, and I'm seeing slightly different behaviour. Previously I was using a non-blank DFS disk. Now when I do a *CAT it seems to access track 0 in single density (latch=00), then switches to double density...
by hoglet
Wed Aug 12, 2020 8:55 pm
Forum: 8-bit acorn hardware
Topic: Kenda "The Professional" DMFS
Replies: 59
Views: 992

Re: Kenda "The Professional" DMFS

I've so far only seen changes written to bit 0, which is drive select, and bit 7 which is still ambiguous. The latch bits I listed above are for the Acorn 1770 interface. As far as I can tell so far, the latch is expected to be at &FE84 and so far I have seen: - bit 0 is the drive select (0=Drive 0...
by hoglet
Wed Aug 12, 2020 7:16 pm
Forum: 8-bit acorn hardware
Topic: Kenda "The Professional" DMFS
Replies: 59
Views: 992

Re: Kenda "The Professional" DMFS

This is a great thread.... I've hacked the ROM a little in an attempt to make it run against my Model B's Acorn 1770 disk interface. (It seems to work fine in sideways RAM; the 2KB RAM appears to be mapped to B000-B7FF). I made a few changes: 1. For all instructions that read/write addresses in the ...
by hoglet
Wed Aug 12, 2020 2:54 pm
Forum: 8-bit acorn hardware
Topic: Silent, nothing visible
Replies: 118
Views: 1817

Re: Silent, nothing visible

There are two traces that would be useful to see, as they indicate what's happening to the processor just after reset: - Channel 1 = pin 7 (Sync) ; Channel 2 = 40 (nRST), trigger off the rising edge of channel 2, timebase about 1us per division - Channel 1 = pin 34 (RnW) ; Channel 2 = 40 (nRST), tri...
by hoglet
Tue Aug 11, 2020 2:59 pm
Forum: 8-bit acorn hardware
Topic: Clearing EPROMS/EEPROMS
Replies: 52
Views: 839

Re: Clearing EPROMS/EEPROMS

I'm sure Mark will correct me if I'm wrong here, but I think when programming Tricky's Test ROM into a 27C512 it needs to be placed at offset 0xC000 within the EPROM, not 0x4000. This is because a 27C512 is a 64KB EPROM, and both A14 (pin 27) and A15 (pin 1) are connected on IC51 on the Model B. Dave
by hoglet
Mon Aug 10, 2020 2:53 pm
Forum: acorn atom and acorn system series
Topic: Atom Video to HDMI Adapter
Replies: 266
Views: 18818

Re: Atom Video to HDMI Adapter

thecellartroll wrote:
Mon Aug 10, 2020 2:43 pm
Now I have a new soldering iron, a hot air blowing doobery and a bucket of solder paste, could I please order a pair of boards if any are left? :D
PM sent....
by hoglet
Sun Aug 09, 2020 6:36 pm
Forum: 8-bit acorn emulators
Topic: MAME: Hybrid Music 5000
Replies: 10
Views: 293

Re: MAME: Hybrid Music 5000

Can you also explain what happens in the other time slots initiated by /S0, /S1, /S4, /S6, /S7. It's a pretty complex pipelined design, and I don't recall exactly how the pipeline was laid out. So I'd need to go back to the VHDL and work this out again: https://github.com/hoglet67/Music5000/blob/ma...
by hoglet
Sun Aug 09, 2020 8:18 am
Forum: 8-bit acorn emulators
Topic: MAME: Hybrid Music 5000
Replies: 10
Views: 293

Re: MAME: Hybrid Music 5000

Thanks. I understand all of this from the documentation and the b-em implementation, but what I don't understand is how the hardware uses those four control bits of the stereo position to affect what is fed to the Am6070 to result in the 7 positions. What does IC24 actually do to achieve this? IC24...
by hoglet
Sat Aug 08, 2020 7:23 pm
Forum: 8-bit acorn emulators
Topic: MAME: Hybrid Music 5000
Replies: 10
Views: 293

Re: MAME: Hybrid Music 5000

Nigel, I can try to help you out with this tomorrow, if no one else beats me to it. Each channel has a stereo position which controls for how many time slots the channel is sent to the left channel vs the right channel (I think there are 6 time slots in total). The counter you mention controls when ...
by hoglet
Sat Aug 01, 2020 1:30 pm
Forum: acorn atom and acorn system series
Topic: Atom Software Archive
Replies: 1257
Views: 189087

Re: Atom Software Archive

(Thanks to BigEd for promopting this research) Now that most issues early issues of Personal Computer World are now available online , we can add a few more programs to the archive. This page is just my notes on what's available, and what's worth adding. My starting point was the index here . "Missi...
by hoglet
Thu Jul 30, 2020 7:22 am
Forum: acorn atom and acorn system series
Topic: Yarrb - redesigned
Replies: 226
Views: 10584

Re: Yarrb - redesigned

cjm wrote:
Wed Jul 29, 2020 10:45 pm
For example: I am surprised the MMC works, I thought I might have to add exxx to the clock stretched area.
With the latest ROM/Firmware, AtoMMC should work at 4MHz.

Dave
by hoglet
Tue Jul 28, 2020 7:20 am
Forum: programming
Topic: OSBGET
Replies: 9
Views: 307

Re: OSBGET

If you want more help, then you probably need to post the complete thing (e.g. as a .ssd file)

Dave
by hoglet
Mon Jul 27, 2020 9:26 pm
Forum: programming
Topic: OSBGET
Replies: 9
Views: 307

Re: OSBGET

You have X and Y the correct way arround (X is the low byte, Y is the hi byte of the address)

The filename needs a terminator (a &0D byte); without this OSFIND is likely to fail.

Dave
by hoglet
Mon Jul 27, 2020 4:07 pm
Forum: 8-bit acorn hardware
Topic: PiTube - *FX151 230 n seems odd
Replies: 14
Views: 502

Re: PiTube - *FX151 230 n seems odd

I had completely forgotten that there was an internal Master Pi Tube adapter (that'll teach me for tidying things away in boxes in a cupboard instead of leaving them where I can see them and trip over them every day). What happens with both fitted? By both, do you mean an internal and external PiTu...
by hoglet
Mon Jul 27, 2020 1:23 pm
Forum: 8-bit acorn hardware
Topic: PiTube - *FX151 230 n seems odd
Replies: 14
Views: 502

Re: PiTube - *FX151 230 n seems odd

No, I do mean *CO. NOTUBE. This is for the situation where I want to switch off the second processor. Selecting the null processor doesn't work the way my machine is set up, but NOTUBE switches it off perfectly! I suspect the null processor was intended for BBC B users who don't have the NOTUBE fac...
by hoglet
Mon Jul 27, 2020 8:41 am
Forum: 8-bit acorn hardware
Topic: PiTube - *FX151 230 n seems odd
Replies: 14
Views: 502

Re: PiTube - *FX151 230 n seems odd

jms2 wrote:
Mon Jul 27, 2020 8:12 am
Is this intube/extube thing anything to do with the way that *fx151 doesn't work the first time? That's not been mentioned before.
It might, it does get very confusing when there are multiple Co Processors present.
by hoglet
Mon Jul 27, 2020 7:28 am
Forum: 8-bit acorn hardware
Topic: PiTube - *FX151 230 n seems odd
Replies: 14
Views: 502

Re: PiTube - *FX151 230 n seems odd

On a Master with a single external PiTubeDirect, make sure you have *CONFIG INTUBE set

(i.e. the opposite of what you might expect!)
by hoglet
Thu Jul 23, 2020 7:12 pm
Forum: 8-bit acorn hardware
Topic: XC9500XL phaseout
Replies: 27
Views: 1355

Re: XC9500XL phaseout

And back to normal again... XC9572XL-1-VQG44C is now down to £3.05 + VAT at Farnell; actually a whole 34p cheaper that the last time I bought some prior to COVID-19. https://uk.farnell.com/xilinx/xc9572xl-10vqg44c/cpld-flash-10ns-100mhz-vqfp-44/dp/2831287?scope=partnumberlookahead&ost=XC9572XL-10VQG...
by hoglet
Thu Jul 23, 2020 12:35 pm
Forum: new projects and releases: demoscene
Topic: New hardware trick: "vertical rupture" on the Acorn Electron
Replies: 27
Views: 932

Re: New hardware trick: "vertical rupture" on the Acorn Electron

That's an interesting thought. I did make some demo effects before in ROM for extra speed (in SWRAM actually). In my stable raster code all interrupts are off anyway and I don't use the stack. I should then only avoid using zeropage and then everything will execute at 2MHz with no memory contention...
by hoglet
Thu Jul 23, 2020 12:17 pm
Forum: new projects and releases: demoscene
Topic: New hardware trick: "vertical rupture" on the Acorn Electron
Replies: 27
Views: 932

Re: New hardware trick: "vertical rupture" on the Acorn Electron

I think a mode change (MODE 0-3) that overlaps the start of each scanline is impossible because the CPU is then stalled until HSYNC, effectively leavning no room to switch back to MODE 4-6 during the remainder of that scanline. Yes, you are right, that would only work if the code was in sideways RO...
by hoglet
Thu Jul 23, 2020 11:47 am
Forum: new projects and releases: demoscene
Topic: New hardware trick: "vertical rupture" on the Acorn Electron
Replies: 27
Views: 932

Re: New hardware trick: "vertical rupture" on the Acorn Electron

@DaveB (or somebody else): maybe you could help me figure this out. I can have a try.... When the ends of lines 0..6 are reached, the video address counter is re-loaded from the internal "start of row" register (QSTART on the Schematics). So any extra bytes "eaten" by switching to mode 0 at the end...
by hoglet
Wed Jul 22, 2020 11:09 pm
Forum: 8-bit acorn hardware
Topic: Acorn Electron online? Any such hardware.
Replies: 93
Views: 4513

Re: Acorn Electron online? Any such hardware.

Will there be any way to work around that 40 usec delay in MODE0-3? I don't know the Electron that well. This is my third real serious project for the Electron so although I own my Elk also more than 30 years the machine is still new to me. I can think of three ways: 1. Don't access main memory dur...
by hoglet
Wed Jul 22, 2020 9:19 pm
Forum: 8-bit acorn hardware
Topic: Acorn Electron online? Any such hardware.
Replies: 93
Views: 4513

Re: Acorn Electron online? Any such hardware.

Nice work Roland.

Dave
by hoglet
Wed Jul 22, 2020 4:32 pm
Forum: 8-bit acorn hardware
Topic: RGB to HDMI using a Pi Zero and a small CPLD
Replies: 1187
Views: 83014

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

No visible effect that I can see I think what's happening here is that RGBtoHDMI is not detecting the video as mode 7 (i.e. interlaced) and is thus failing to engage the approriate capture code and deinterlacing. That's why the characters look ugly and jagged, very unlike what "mode 7" on the Beeb ...

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