Search found 432 matches

by KenLowe
Sun Jan 20, 2019 9:41 pm
Forum: hardware
Topic: New ROM / RAM Expansion Board for BBC B
Replies: 26
Views: 547

Re: New ROM / RAM Expansion Board for BBC B

1024MAK wrote:
Sun Jan 20, 2019 9:40 pm
As a well known TV commercial tag line goes, every little helps :wink:
Mark
Indeed.
by KenLowe
Sun Jan 20, 2019 8:56 pm
Forum: hardware
Topic: New ROM / RAM Expansion Board for BBC B
Replies: 26
Views: 547

Re: New ROM / RAM Expansion Board for BBC B

Speaking of which, are you intending to use low power CMOS versions of the glue logic, such as 74HCTxxx chips? Yes. All 74 series glue logic ICs will be 74HCTs. There's not actually that many of them (7 in total). Most of the address decoding logic is done in two PALs (although I'll be using GALs)....
by KenLowe
Sun Jan 20, 2019 1:53 pm
Forum: hardware
Topic: New ROM / RAM Expansion Board for BBC B
Replies: 26
Views: 547

Re: New ROM / RAM Expansion Board for BBC B

Board layout progressing well. Still to add the RTC & battery / charging circuit to the top RHS of the board, and sort out some of the power distribution...
by KenLowe
Wed Jan 16, 2019 9:45 am
Forum: hardware
Topic: New ROM / RAM Expansion Board for BBC B
Replies: 26
Views: 547

Re: New ROM / RAM Expansion Board for BBC B

RobC wrote:
Tue Jan 15, 2019 7:30 pm
Should have said that I had to contact them when I bought mine years ago. They were very helpful and were happy to order a handful in for me.
That's the APA-640-T-P added to their web page, and an order placed for a batch of ten. £4.10 + VAT per unit + delivery!
by KenLowe
Tue Jan 15, 2019 11:14 pm
Forum: hardware
Topic: POLL: How much Sideways RAM?
Replies: 20
Views: 493

Re: POLL: How much Sideways RAM?

I've got 4 x 16k RAM banks in my IntegraB. It's possible to add another 8 RAM banks (via 4 x 32k RAM ICs) to the board, but I generally use EPROMs/ EEPROMs in those slots. I've got other beebs, with other ROM / RAM expansion boards (2 x IFEL + 1 x kjell / Sundby), but I find the IntegraB to be the m...
by KenLowe
Tue Jan 15, 2019 8:40 pm
Forum: hardware
Topic: New ROM / RAM Expansion Board for BBC B
Replies: 26
Views: 547

Re: New ROM / RAM Expansion Board for BBC B

I use SIL pins and a stack of sockets... effective and not entirely ugly :lol: Marcus Sorry. Missed your post earlier. I've done similar in the past, but was looking for something a little bit more 'professional'. I've emailed Toby for price & delivery. For reference, I've taken a photograph of the...
by KenLowe
Tue Jan 15, 2019 7:21 pm
Forum: hardware
Topic: New ROM / RAM Expansion Board for BBC B
Replies: 26
Views: 547

Re: New ROM / RAM Expansion Board for BBC B

Are these Samtec APA plugs the right sort of thing? Not cheap but I bought a few 640s when I wanted to repair my Watford ROM/RAM board. Many thanks for the link. The APA-640-T-P is exactly what I'm looking for. Unfortunately, this one isn't available for sale on their website, so I'll need to conta...
by KenLowe
Tue Jan 15, 2019 6:10 pm
Forum: hardware
Topic: New ROM / RAM Expansion Board for BBC B
Replies: 26
Views: 547

Re: New ROM / RAM Expansion Board for BBC B

The one component I'm struggling to source is a 40 pin dil (or 2 20 pin sil) round pin header, approx 25mm long, that would solder to the underside of the board, and then plug into 6502 socket on the BBC motherboard. I can find plenty of sil headers, but these have square pins, and tend to damage th...
by KenLowe
Tue Jan 15, 2019 12:26 pm
Forum: hardware
Topic: New ROM / RAM Expansion Board for BBC B
Replies: 26
Views: 547

Re: New ROM / RAM Expansion Board for BBC B

Hi Ken - this sounds like an amazing expansion board, great work! One question I have - how does the SHADOW RAM work; Is it possible to do 'Master style' double-buffering, i.e. have the CPU write to one memory bank whilst the CRTC 6845 video chip reads from the other? Nothing that elaborate, I'm af...
by KenLowe
Tue Jan 15, 2019 11:59 am
Forum: hardware
Topic: New ROM / RAM Expansion Board for BBC B
Replies: 26
Views: 547

Re: New ROM / RAM Expansion Board for BBC B

PCB design is almost complete, and I will be looking to place an order for a prototype PCB in the very near future. One off costs are quite high, but come down considerably if I order in bulk. Might be worth considering https://www.allpcb.com they are quite reasonable for runs of 5 boards, it would...
by KenLowe
Tue Jan 15, 2019 8:57 am
Forum: hardware
Topic: New ROM / RAM Expansion Board for BBC B
Replies: 26
Views: 547

Re: New ROM / RAM Expansion Board for BBC B

marcusjambler wrote:
Tue Jan 15, 2019 8:54 am
assuming its through hole components
Yes. Everything will be through hole.
by KenLowe
Tue Jan 15, 2019 12:18 am
Forum: hardware
Topic: New ROM / RAM Expansion Board for BBC B
Replies: 26
Views: 547

New ROM / RAM Expansion Board for BBC B

Ok folks. I'm edging ever closer to finalising a replica IntegraB sideways / shadow / RTC board for the BBC model B, which (rather unashamedly) will be an almost identical copy of the original board, using the same or equivalent components. The board will consist of the following: 8 x Expansion sock...
by KenLowe
Fri Jan 11, 2019 12:51 pm
Forum: general
Topic: Which games from other platforms did you wish was on the BBC?
Replies: 63
Views: 4224

Re: Which games from other platforms did you wish was on the BBC?

RobC wrote:
Fri Jan 11, 2019 11:02 am
Maybe we could look at porting Frotz to the Pi co-pro...
That would be awesome, but possibly a bit unnecessary. It is actually possible to get it running on a Z80 co-pro:

viewtopic.php?f=3&t=6727&hilit=Zork+z80 ... 60#p107157
by KenLowe
Wed Jan 09, 2019 11:28 pm
Forum: general
Topic: Which games from other platforms did you wish was on the BBC?
Replies: 63
Views: 4224

Re: Which games from other platforms did you wish was on the BBC?

Zork, and other Infocom adventures. It always annoyed me that these were available for the Apple IIe but not the Beeb.
Money Island and Lost Vikings, although these might be a bit more modern than the Beeb was ever capable of.
by KenLowe
Mon Jan 07, 2019 6:18 pm
Forum: hardware
Topic: Sideways RAM on the BBC Micro
Replies: 48
Views: 2740

Re: Sideways RAM on the BBC Micro

Hmm. Those parts are £10.52+VAT at Mouser in quantities of 100. Is that eBay price cheap, or too cheap? I'll let you know when they arrive! More of an issue, although that Cypress device is 5V-tolerant, its Voh1 is only 2.4V. While fine for TTL, that's conspicuously below the 2.7V minimum Vh of 5V ...
by KenLowe
Mon Jan 07, 2019 12:59 am
Forum: hardware
Topic: Sideways RAM on the BBC Micro
Replies: 48
Views: 2740

Re: Sideways RAM on the BBC Micro

Sounds like you need something like this . I think the diodes are there to drop the supply voltage to Vcc down from 5v to 3.3v, and the jumper is to short out the diodes to put 5v directly onto Vcc. Not sure how the other pins will cope with 5v signals. Assuming the signal pins are tolerant to 5v, t...
by KenLowe
Sun Jan 06, 2019 9:37 pm
Forum: hardware
Topic: SCSI Host Adapter
Replies: 0
Views: 108

SCSI Host Adapter

Hi, I've got several old school Fujitsu SCSI HDDs that can be formatted to 256 byte sectors and I'm looking to build some host adaptors so I can hook them up to my Beebs. I've been reviewing the BeebSCSI documentation here , and this thread , and was keen to use the XC9572XL solution that Simon has ...
by KenLowe
Wed Jan 02, 2019 2:31 pm
Forum: hardware
Topic: AP6 ROM update issues
Replies: 40
Views: 708

Re: AP6 ROM update issues

And I've gone through the following procedure and can pronounce it works just fine . . . With one caveat! When I first tried, it failed in a similar way Richard was seeing. It turned out that I had one of the 28C256 parts that was 'locked' and wouldn't respond to unlocking using MartinB's UNLOCK ut...
by KenLowe
Wed Dec 19, 2018 6:06 pm
Forum: off-topic
Topic: 3D Printing
Replies: 11
Views: 618

Re: 3D Printing

Well, I'm glad I didn't go for the first offer I saw. Instead of paying £60, i can now get it for £25: https://www.greatflux.com/collections/frontpage/products/3dprinter Seriously????? I think it really does show this up as a complete scam. Annoyingly, these are continually appearing as ads on Faceb...
by KenLowe
Wed Dec 19, 2018 12:12 pm
Forum: hardware
Topic: BBC Model B faults
Replies: 16
Views: 546

Re: BBC Model B faults

Hinotori wrote:
Mon Dec 17, 2018 2:24 pm
The form of visual corruption changes depending on which MODE it is in.
What actually happens if you switch to a different mode (eg MODE 1) and run your test again?
by KenLowe
Tue Dec 18, 2018 5:49 pm
Forum: projects
Topic: A new MENU system for MMC/Gotek/ (GOTEK working)
Replies: 55
Views: 1927

Re: A new MENU system for MMC/Gotek/ (GOTEK working)

Do you have the correct firmware on the Gotek? You should be on 0.14 (currently the latest version).
by KenLowe
Sun Dec 16, 2018 12:58 am
Forum: hardware
Topic: Three Floppy Drives in Master 128
Replies: 14
Views: 466

Re: Three Floppy Drives in Master 128

The Shugart Associates interface actually is capable of supporting four devices (disk drives and back-up tape units). Trouble is that ADFS expects all devices to be on the same SCSI address and selects different devices by switching LUN. Many more modern SCSI devices can't be configured in this way...
by KenLowe
Thu Dec 06, 2018 10:10 am
Forum: off-topic
Topic: Data recovery from eMMC
Replies: 5
Views: 301

Re: Data recovery from eMMC

So, I sent the logic board away to the company that I linked earlier, and I must say, I have been very impressed with the service. Received a USB stick back from them yesterday with the entire emmc disk structure copied across. From that I have managed to recover all the critical files from the C:\U...
by KenLowe
Mon Dec 03, 2018 9:48 pm
Forum: hardware
Topic: I2C 4 U
Replies: 301
Views: 19463

Re: I2C 4 U

That fixed it =D> =D> =D>
by KenLowe
Mon Dec 03, 2018 8:56 pm
Forum: hardware
Topic: I2C 4 U
Replies: 301
Views: 19463

Re: I2C 4 U

The three commands I suggested above allow you to turn temperature on and off without disturbing ToB which is of course toggled with *TBRK. Duh. I forgot about that! Just tested *TBRK but it doesn't seem to be working correctly. I think it reads the state correctly, but doesn't appear to change the...
by KenLowe
Mon Dec 03, 2018 8:19 pm
Forum: hardware
Topic: I2C 4 U
Replies: 301
Views: 19463

Re: I2C 4 U

Here we go Ken, version 3.1K for you to try on your setup. I haven’t been able to test the changes because I don’t have one of your module types and whilst I wrote some DS3231 emulation for BeebEm to test the mainstream versions of the rom, I don’t have time (and it wouldn’t be worth the effort tbh...
by KenLowe
Mon Dec 03, 2018 1:58 pm
Forum: hardware
Topic: I2C 4 U
Replies: 301
Views: 19463

Re: I2C 4 U

I use Android :lol: :lol: :lol: :wink:
by KenLowe
Mon Dec 03, 2018 12:32 am
Forum: hardware
Topic: I2C 4 U
Replies: 301
Views: 19463

Re: I2C 4 U

Thanks Martin. I'll give it a go tomorrow (actually today, now) evening once I get back from work.
by KenLowe
Sun Dec 02, 2018 6:58 pm
Forum: hardware
Topic: Sharing a Disk Drive
Replies: 21
Views: 1640

Re: Sharing a Disk Drive

Also liking the power cable 'clamp!

Edit: In both systems!
by KenLowe
Sun Dec 02, 2018 4:43 pm
Forum: software: classic games
Topic: Graphic adventures
Replies: 17
Views: 814

Re: Graphic adventures

I'd recommend The Hunt: Search For Shauna by Robico, or some of the later Level 9 games - Lancelot, Time & Magik, Scapegoat, Ingrid's Back, Gnome Ranger & The Secret Diary Of Adrian Mole Aged 13 3/4. The only thing is that the Level 9 games require either a Master, BBC B+, or a BBC with both sideway...