Search found 812 matches

by flynnjs
Tue Jun 06, 2017 6:19 pm
Forum: for sale / freebies
Topic: Offered: Matchbox sized 6502 / Z80 / 6809 Co Pro
Replies: 603
Views: 70011

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 6:15 pm
Forum: hardware
Topic: Cheap Xilinx LX9 Starter Board
Replies: 30
Views: 4017

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 7:49 pm
Forum: off-topic
Topic: x86 Internals for Fun & Profit
Replies: 12
Views: 1580

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 7:23 pm
Forum: hardware
Topic: What to try re-engineering next.....
Replies: 29
Views: 3383

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 5:07 pm
Forum: off-topic
Topic: x86 Internals for Fun & Profit
Replies: 12
Views: 1580

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 4:21 pm
Forum: for sale / freebies
Topic: Offered: Matchbox sized 6502 / Z80 / 6809 Co Pro
Replies: 603
Views: 70011

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 3:39 pm
Forum: software: other
Topic: Restarting new BASIC program
Replies: 13
Views: 1317

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 3:14 pm
Forum: software: other
Topic: Restarting new BASIC program
Replies: 13
Views: 1317

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 9:51 am
Forum: software: other
Topic: Restarting new BASIC program
Replies: 13
Views: 1317

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 9:34 am
Forum: hardware
Topic: What to try re-engineering next.....
Replies: 29
Views: 3383

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 5:16 pm
Forum: software: other
Topic: Sideways RAM Utilities
Replies: 68
Views: 6141

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 1:32 pm
Forum: software: other
Topic: Sideways RAM Utilities
Replies: 68
Views: 6141

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
Wed May 24, 2017 11:30 pm
Forum: for sale / freebies
Topic: New TEAC floppy drives
Replies: 55
Views: 6677

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 9:15 pm
Forum: for sale / freebies
Topic: New TEAC floppy drives
Replies: 55
Views: 6677

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 8:42 pm
Forum: for sale / freebies
Topic: New TEAC floppy drives
Replies: 55
Views: 6677

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 7:35 pm
Forum: for sale / freebies
Topic: New TEAC floppy drives
Replies: 55
Views: 6677

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 6:06 pm
Forum: hardware
Topic: Palettemate / enhanced video ULA with 4096 colours
Replies: 595
Views: 59026

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 5:59 pm
Forum: for sale / freebies
Topic: New TEAC floppy drives
Replies: 55
Views: 6677

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 5:11 pm
Forum: for sale / freebies
Topic: New TEAC floppy drives
Replies: 55
Views: 6677

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 7:54 am
Forum: for sale / freebies
Topic: New TEAC floppy drives
Replies: 55
Views: 6677

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?
by flynnjs
Sat May 20, 2017 11:03 pm
Forum: hardware
Topic: The Master List for New Retro Hardware
Replies: 105
Views: 24765

Re: A Master List for New Retro Kit?

I would have thought a retrohardware wiki would be more appropriate.
by flynnjs
Sat May 20, 2017 7:05 pm
Forum: for sale / freebies
Topic: Offered: Matchbox sized 6502 / Z80 / 6809 Co Pro
Replies: 603
Views: 70011

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

I will post the pcb designs.

I have a new faster bigger better board coming out soon with an insane feature set at what should also be "a very reasonable price".
by flynnjs
Tue May 16, 2017 9:01 pm
Forum: hardware
Topic: New to the Atom, needs advice
Replies: 7
Views: 724

Re: New to the Atom, needs advice

GODILs are on offer at the moment 45 Euro:
https://shop.trenz-electronic.de/en/TE0 ... -IDC?c=191
by flynnjs
Mon May 15, 2017 10:14 pm
Forum: acorn atom and system
Topic: Matchbox sized 6502 / Z80 / 6809 Co Pro
Replies: 1203
Views: 119051

Re: Matchbox sized 6502 / Z80 / 6809 Co Pro

I've just soldered up a board for myself this evening (as I haven't had one for months!). After programming it and testing it, I too noticed that and was mulling over why this board was doing something that I hadn't seen this weekend. Many of the boards I tested at Cambridge were defaulting to somet...
by flynnjs
Sun May 14, 2017 8:39 pm
Forum: acorn atom and system
Topic: Matchbox sized 6502 / Z80 / 6809 Co Pro
Replies: 1203
Views: 119051

Re: Matchbox sized 6502 / Z80 / 6809 Co Pro

If you have RAM ending in EBLL, yes, you most definitely need to.

If you have RAM with DBLL then you may get away with slightly more aggressive speeds and use Dave's Nov '16 build.
by flynnjs
Sun May 14, 2017 6:12 pm
Forum: past events & exhibitions
Topic: May 12th-14th 2017 Cambridge ABUG (FULL) & Acorn World event at CCfCH
Replies: 190
Views: 22650

Re: May 12th-14th 2017 Cambridge ABUG (FULL) & Acorn World event at CCfCH

Thanks to everyone that made this event what it was, esp jbnbeeb who went an extra mile to make it so superb.
Great organised display all sorts of Acorn stuff in addition to the meetup. Well done!
by flynnjs
Sun May 14, 2017 6:10 pm
Forum: acorn atom and system
Topic: Matchbox sized 6502 / Z80 / 6809 Co Pro
Replies: 1203
Views: 119051

Re: Matchbox sized 6502 / Z80 / 6809 Co Pro

I checked each would boot and at minimum issued some star commands.
In the case of Z80 I also ran BASIC
In the case of x86 I also ran DOS

I didn't get time to exercise the paged RAM on 6502.
by flynnjs
Sun May 14, 2017 5:37 pm
Forum: acorn atom and system
Topic: Matchbox sized 6502 / Z80 / 6809 Co Pro
Replies: 1203
Views: 119051

Re: Matchbox sized 6502 / Z80 / 6809 Co Pro

Thanks, that build seems 100% reliable on the rev E RAM.
The datasheet for the RAM gives the same timing figures but they've obviously changed something internally to make it less overclockable.
by flynnjs
Sun May 14, 2017 12:01 pm
Forum: acorn atom and system
Topic: Matchbox sized 6502 / Z80 / 6809 Co Pro
Replies: 1203
Views: 119051

Re: Matchbox sized 6502 / Z80 / 6809 Co Pro

The latest are IS66WV51216EBLL-70 Previous had been IS66WV51216DBLL-70. There could also be some with IS62 series too. I have two identical PCBs one with the D revision RAM and another with the E revision. The D is OK at 16 MHz and the is E isn't. As an interim just running the whole ARM slower migh...
by flynnjs
Sun May 14, 2017 11:33 am
Forum: acorn atom and system
Topic: Matchbox sized 6502 / Z80 / 6809 Co Pro
Replies: 1203
Views: 119051

Re: Matchbox sized 6502 / Z80 / 6809 Co Pro

Dave,
thanks for that. I went straight for 12MHz build and x86 DOS is now 100% stable :D

The ARM is still very iffy. Does that push the RAM limits too?