Search found 822 matches

by flynnjs
Mon Jul 03, 2017 8:04 pm
Forum: for sale / freebies
Topic: BeebSCSI mini
Replies: 168
Views: 23188

Re: BeebSCSI mini

I shall do another batch but I need to gauge interest, so I'll run a list here for a week or so.
by flynnjs
Mon Jun 19, 2017 5:35 pm
Forum: 8-bit acorn hardware
Topic: Acorn IC die shots
Replies: 4
Views: 948

Re: Acorn IC die shots

dp11 wrote:The top one doesn't really have enough pads to be anything from the Archimedes I don't think.
I guess, as Ed said, only 27 pads. Seems quite high density and too irregular to be a ULA.
Did Master/Compacts every have anything full ASIC?
by flynnjs
Mon Jun 19, 2017 5:18 pm
Forum: 8-bit acorn hardware
Topic: Acorn IC die shots
Replies: 4
Views: 948

Re: Acorn IC die shots

I had assumed that the bottom one was possibly a ULA of some type. The other I thought was very processor like or possible processor support IC. They were in the tray with a ceramic quad flat pack with "Engineering Sample" written on the top. This engineering sample was the same size and had the sam...
by flynnjs
Sun Jun 18, 2017 5:36 pm
Forum: 8-bit acorn hardware
Topic: Domesday86 Project
Replies: 82
Views: 8036

Re: Domesday86 Project

I may replace the micro sd socket with a full size one so that I can drop adfs images on using a wifi-sd card. Disappointingly, this won't work as the wifi-sd cards only boot when connected to an SD host controller in full SD mode and don't work when in SPI mode. Looking at the fat-fs documentation...
by flynnjs
Sun Jun 18, 2017 11:31 am
Forum: 8-bit acorn hardware
Topic: Help with voltage overload protection on Analogue in
Replies: 29
Views: 2881

Re: Help with voltage overload protection on Analogue in

could anyone explain to me the difference between the 0V pins and the Analogue Ground pins? Pin 8 on the analogue port is connected to 0V on the Beeb motherboard so they are logically the same. However, the AGND pin will be connected in the shortest possible route to the AGND pin of the ADC which i...
by flynnjs
Thu Jun 15, 2017 12:53 pm
Forum: 8-bit acorn hardware
Topic: OS RAM module
Replies: 84
Views: 9019

Re: OS RAM module

cmorley wrote: It seems perfectly happy with either data and/or program in high RAM. You just need to massage LOMEM & HIMEM in the correct order if you want PAGE>LOMEM.
This is not surprising as non HiBasic could be used just this way when copied to the 2nd Proc?
by flynnjs
Mon Jun 12, 2017 1:07 am
Forum: for sale / freebies
Topic: BeebSCSI mini
Replies: 168
Views: 23188

Re: BeebSCSI mini

Yes, I'll be doing some more but I need to get another batch of PCBs in first.
by flynnjs
Sun Jun 11, 2017 7:46 am
Forum: other vintage hardware, software and languages
Topic: Can someone explain why YUV output doesn't work?
Replies: 6
Views: 1631

Re: Can someone explain why YUV output doesn't work?

It's possible the TV only supports component input at HD resolutions. Best check the TV user manual.
by flynnjs
Fri Jun 09, 2017 9:02 am
Forum: for sale / freebies
Topic: BeebSCSI mini
Replies: 168
Views: 23188

BeebSCSI mini

I'm pleased to announce that I've made up a few BeebSCSI minis and made them available on my webshop. Many thanks to Simon for his design and efforts (see: http://www.domesday86.com/?page_id=400) My version is a direct copy other than using SMD termination resistors and shrinking the PCB so that it ...
by flynnjs
Fri Jun 09, 2017 8:42 am
Forum: 8-bit acorn hardware
Topic: Acorn IC die shots
Replies: 4
Views: 948

Acorn IC die shots

At the Cambridge meetup, I took these snaps of some wafers that were in a box at the centre.
They are of Acorn heritage but we weren't sure what they might be. Any ideas?
IMG_0854.JPG
IMG_0855.JPG
by flynnjs
Tue Jun 06, 2017 7:19 pm
Forum: for sale / freebies
Topic: Offered: Matchbox sized 6502 / Z80 / 6809 Co Pro
Replies: 603
Views: 81467

Re: Offered: Matchbox sized 6502 / Z80 / 6809 Co Pro

A bit surprised that people were nagging for more of these and when I
do so there is little interest.
by flynnjs
Tue Jun 06, 2017 7:15 pm
Forum: 8-bit acorn hardware
Topic: Cheap Xilinx LX9 Starter Board
Replies: 43
Views: 6117

Re: Cheap Xilinx LX9 Starter Board

More than £11 in small quantities... £11 plus VAT at least! The adapter worked first time and I got Dave's ICE working on the LX9 so as a minimum was an upgrade and cheaper than the GoDIL which is Spartan 3 based. As for the evolution, it's odd that you ask, because I'd not done anything on it until...
by flynnjs
Fri Jun 02, 2017 8:49 pm
Forum: off-topic
Topic: x86 Internals for Fun & Profit
Replies: 12
Views: 1877

Re: x86 Internals for Fun & Profit

The fastest RAM cells (including L1 cache) are around 1ns.
25 years ago, 386 cache was about 10ns.
And the size isn't much different either.
by flynnjs
Fri Jun 02, 2017 8:23 pm
Forum: 8-bit acorn hardware
Topic: What to try re-engineering next.....
Replies: 44
Views: 5356

Re: What to try re-engineering next.....

hoglet wrote:The diodes are drawn backwards I think.
Just making sure everyone is awake :)
by flynnjs
Fri Jun 02, 2017 6:07 pm
Forum: off-topic
Topic: x86 Internals for Fun & Profit
Replies: 12
Views: 1877

Re: x86 Internals for Fun & Profit

Actually, evolution beyond original design isn't the main reason CPUs are so complex. It's more down to the fact RAM just hasn't become significantly faster and the complexity is just a load of hacks to try to avoid being held up by RAM. If you like crazy CPU arch then go check out the Mill: https:/...
by flynnjs
Fri Jun 02, 2017 5:21 pm
Forum: for sale / freebies
Topic: Offered: Matchbox sized 6502 / Z80 / 6809 Co Pro
Replies: 603
Views: 81467

Re: Offered: Matchbox sized 6502 / Z80 / 6809 Co Pro

I've made a few more of these available on the webshop.
These will be made to order using the remaining PCBs I have.
by flynnjs
Fri Jun 02, 2017 4:39 pm
Forum: 8-bit acorn software: other
Topic: Restarting new BASIC program
Replies: 13
Views: 1680

Re: Restarting new BASIC program

A quick check, recursively starting BASIC doesn't appear to overflow the 6502 stack so
BASIC must be resetting it somewhere.
by flynnjs
Fri Jun 02, 2017 4:14 pm
Forum: 8-bit acorn software: other
Topic: Restarting new BASIC program
Replies: 13
Views: 1680

Re: Restarting new BASIC program

I think the best way to do this which doesn't require calling directly into BASIC internal routines is just to insert a line into the keyboard buffer to set PAGE and RUN, then exit to BASIC. But if my machine code was originally called by BASIC CALL then won't there will still be a call on the stac...
by flynnjs
Fri Jun 02, 2017 10:51 am
Forum: 8-bit acorn software: other
Topic: Restarting new BASIC program
Replies: 13
Views: 1680

Restarting new BASIC program

If call out from a BASIC program to a bit of machine code which for example
replaced the original BASIC program with some new BASIC, is there any way of
throwing away the BASIC stack and starting again?
by flynnjs
Fri Jun 02, 2017 10:34 am
Forum: 8-bit acorn hardware
Topic: What to try re-engineering next.....
Replies: 44
Views: 5356

Re: What to try re-engineering next.....

I've been pawing over the schematic for the TWOMEG-128 trying to check that it all looks sane and correct but also trying to figure out how it works. For reference, this is my description corresponding to the schematic in a previous post (which I've just updated): Address decoding: A set of diodes, ...
by flynnjs
Tue May 30, 2017 6:16 pm
Forum: 8-bit acorn software: other
Topic: Sideways RAM Utilities
Replies: 68
Views: 7543

Re: Sideways RAM Utilities

I also have, though not on-line, a disassembly of the Acorn B+/master SRAM, i.e. that bundled into later version of DFS. I have 1.03 (DFS 2.23) and 1.05 (DFS 2.26) in which I have started to put names to the subroutines. This also includes a table giving corresponding addresses for the two version....
by flynnjs
Tue May 30, 2017 2:32 pm
Forum: 8-bit acorn software: other
Topic: Sideways RAM Utilities
Replies: 68
Views: 7543

Re: Sideways RAM Utilities

If DFS is in a higher slot than the Manager ROM then it's possible that a physical machine may not even complete startup! Welcome to my hour of headscratching at Cambridge the other weekend. I thought I'd killed my B somehow but I'd put 2.26 in above the standard STL manager 128 ROM. On my todo lis...
by flynnjs
Thu May 25, 2017 12:30 am
Forum: for sale / freebies
Topic: New TEAC floppy drives
Replies: 62
Views: 8209

Re: New TEAC floppy drives

At the current level of interest (around 10 units) they're going to pretty close to
the £60 mark (including VAT). I'll set up a catalogue item on my webshop at the
weekend.
by flynnjs
Tue May 23, 2017 10:15 pm
Forum: for sale / freebies
Topic: New TEAC floppy drives
Replies: 62
Views: 8209

Re: New TEAC floppy drives

flynnjs wrote:Hi forum, I was thinking about making some 5.25" DS 80T drives available through group purchase.
These are brand new TEAC FD-55F drives. Obviously if we group up then we can get discount
and the postage drops too.

Anyone interested?
by flynnjs
Tue May 23, 2017 9:42 pm
Forum: for sale / freebies
Topic: New TEAC floppy drives
Replies: 62
Views: 8209

Re: New TEAC floppy drives

Elminster wrote:Hmm. Maybe if the price is right. I have serveral external drives with dodgy mechs, that could be replaced.. I assume this is drive only and psu and case are to be provides by us.
Yes, just new bare drive in antistatic bag.
by flynnjs
Tue May 23, 2017 8:35 pm
Forum: for sale / freebies
Topic: New TEAC floppy drives
Replies: 62
Views: 8209

Re: New TEAC floppy drives

pau1ie wrote: Would they be able to read 40 track discs?
Yep, you just need to double-step. You can't repliably write 40T discs as the
head is only half the width.
by flynnjs
Tue May 23, 2017 7:06 pm
Forum: 8-bit acorn hardware
Topic: Palettemate / enhanced video ULA with 4096 colours
Replies: 597
Views: 72884

Re: Palettemate / enhanced video ULA with 4096 colours

The best thing you can do is use LOTS of liquid flux if you're hand soldering.

Solder paste can also be good to use if you have a sane way of applying it.
by flynnjs
Tue May 23, 2017 6:59 pm
Forum: for sale / freebies
Topic: New TEAC floppy drives
Replies: 62
Views: 8209

Re: New TEAC floppy drives

Indeed. I'll leave it another day to see if we get any more interest.
by flynnjs
Tue May 23, 2017 6:11 pm
Forum: for sale / freebies
Topic: New TEAC floppy drives
Replies: 62
Views: 8209

Re: New TEAC floppy drives

I expect these would work out about £60 each given the flurry of interest. That's a lot better than the one-off price I was looking at this morning! They're not "cheap" but getting brand new drives isn't easy any more, let alone non high density capable units. And then HMRC are entitled to their bit...
by flynnjs
Tue May 23, 2017 8:54 am
Forum: for sale / freebies
Topic: New TEAC floppy drives
Replies: 62
Views: 8209

New TEAC floppy drives

Hi list, I was thinking about making some 5.25" DS 80T drives available through group purchase.
These are brand new TEAC FD-55F drives. Obviously if we group up then we can get discount
and the postage drops too.

Anyone interested?

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