Search found 6875 matches

by 1024MAK
Tue Jan 23, 2018 7:18 pm
Forum: hardware
Topic: Acorn's Second Processors and the Tube - what, and why
Replies: 21
Views: 1060

Re: Acorn's Second Processors and the Tube - what, and why

BTW, in an earlier thread we have Steve Furber recollecting: So when the BBC came round looking for a machine, their initial spec was a Z80 running CPM, okay. Now what Acorn offered them was a 6502 running a proprietary operating system. But it said, this is the front end of a two processor machine...
by 1024MAK
Tue Jan 23, 2018 7:11 pm
Forum: hardware
Topic: Acorn's Second Processors and the Tube - what, and why
Replies: 21
Views: 1060

Re: Acorn's Second Processors and the Tube - what, and why

Just as a matter of interest, here are my thoughts on what I think would have been possible in the early 1980s. It would have been possible to design and market a Z80A CPU based home computer that could be compatible with CP/M and which could load some programs from cassette tape. A full CP/M system...
by 1024MAK
Tue Jan 23, 2018 12:25 pm
Forum: hardware
Topic: BBC Model B and DFS Problem
Replies: 31
Views: 419

Re: BBC Model B and DFS Problem

A 150ns EPROM should be fine.

Mark
by 1024MAK
Tue Jan 23, 2018 10:56 am
Forum: hardware
Topic: Connecting SEGA Mega Drive controllers to the beeb
Replies: 25
Views: 431

Re: Connecting SEGA Mega Drive controllers to the beeb

To add to the good advice about PCBs that others have already given, it is sometimes possible to reorder or relocate things like resistors to make the routing easier and more straightforward. In the past, I have designed and built my own designs of PCB manually (with no help from any computer). I wo...
by 1024MAK
Mon Jan 22, 2018 4:32 pm
Forum: hardware
Topic: BBC B Running slow
Replies: 16
Views: 595

Re: BBC B Running slow

The first sound, is the sound chip being powered up with uninitialised data in it's registers (so it then "plays" whatever "data" happens to be in it). Shorty after starting, the OS tells the sound chip to "shut-up" as it updates the sound chips' registers. Then later t...
by 1024MAK
Mon Jan 22, 2018 3:16 pm
Forum: hardware
Topic: Files from modern PC to DFS disk....
Replies: 13
Views: 222

Re: Files from modern PC to DFS disk....

MartinB wrote:
Stephen wrote:For writing an image to floppy, it's hard to beat a UPURS cable and the software Martin wrote :-)

Thank-you Stephen, cheque's in the post as arranged... :- O:)

Still waiting for the cheques from you... :lol:
UPURS does significantly reduce the hassle when copying DFS disk images :D

Mark
by 1024MAK
Mon Jan 22, 2018 10:48 am
Forum: hardware
Topic: SpectROM - Speccy emulator for the Pi co-pro
Replies: 74
Views: 1718

Re: SpectROM - Speccy emulator for the Pi co-pro

RobC wrote:However, I've introduced a bug that I'm yet to find. My daughter heard me talking about it earlier and then told my wife that she's worried that my computer will make me ill :D

She's not wrong. Computers are like a drug addiction... :lol:

Mark
by 1024MAK
Mon Jan 22, 2018 10:12 am
Forum: hardware
Topic: BBC Model B and DFS Problem
Replies: 31
Views: 419

Re: BBC Model B and DFS Problem

Ralf, a thought occurred to me. Just to eliminate one potential problem, can you confirm that the EPROM chips you are using have a suitable fast enough access time (speed).

Mark
by 1024MAK
Mon Jan 22, 2018 10:07 am
Forum: projects
Topic: New game - tube type thingy
Replies: 35
Views: 1218

Re: New game - tube type thingy

Wow! =D> If this does become a playable game, I'm gonna have to be careful that I don't get motion sickness!

Mark
by 1024MAK
Sun Jan 21, 2018 8:58 pm
Forum: hardware
Topic: BBC Model B and DFS Problem
Replies: 31
Views: 419

Re: BBC Model B and DFS Problem

Re- using 32k EPROM chips in an unmodified BBC B. As far as I'm aware, issue 4 and issue 7 boards are okay. But I'm not sure about issue 2 or issue 3 boards...

Mark
by 1024MAK
Sun Jan 21, 2018 7:36 pm
Forum: hardware
Topic: BBC Circuit diagram
Replies: 8
Views: 170

Re: BBC Circuit diagram

I often use the one from here, mainly because I have bookmarks on most of my devices / computers to this page...

But I welcome any good quality scans of schematic drawings =D>

Mark
by 1024MAK
Sun Jan 21, 2018 7:00 pm
Forum: upcoming and recent events & exhibitions
Topic: ABug NORTH User Group meeting | 19-21 JAN 2018 | MANCHESTER *BOOKING INFO*
Replies: 138
Views: 4907

Re: ABug NORTH User Group meeting | 19-21 JAN 2018 | MANCHESTER *BOOKING INFO*

The ABug in Leicestershire (Nov 2017) (link) was in a car friendly rural location.

Mark
by 1024MAK
Sun Jan 21, 2018 5:28 pm
Forum: hardware
Topic: Problem BBC Model B and Turbo MMC
Replies: 30
Views: 597

Re: Problem BBC Model B and Turbo MMC

Ralf continues in his new thread BBC Model B and DFS Problem.

Mark
by 1024MAK
Sun Jan 21, 2018 4:09 pm
Forum: for sale / freebies
Topic: Rombox Plus, Pegasus 400 Disk System etc. for sale
Replies: 10
Views: 352

Re: Rombox Plus, Pegasus 400 Disk System etc. for sale

For new members who currently don't have PM sending privileges, please use the Contact us link at the bottom of any page to ask for your PM privileges to be enabled :wink:

Mark
by 1024MAK
Sun Jan 21, 2018 3:21 pm
Forum: upcoming and recent events & exhibitions
Topic: ABug NORTH User Group meeting | 19-21 JAN 2018 | MANCHESTER *BOOKING INFO*
Replies: 138
Views: 4907

Re: ABug NORTH User Group meeting | 19-21 JAN 2018 | MANCHESTER *BOOKING INFO*

And the last photos from me... IMG_6400.JPG IMG_6401.JPG IMG_6399.JPG Within the next day or so, I'll post links to the cloud storage site with high resolution copies of all the photos that I posted for this event. Thanks to everyone who attended. Another great ABUG event :D =D> Mark
by 1024MAK
Sun Jan 21, 2018 2:06 pm
Forum: upcoming and recent events & exhibitions
Topic: ABug NORTH User Group meeting | 19-21 JAN 2018 | MANCHESTER *BOOKING INFO*
Replies: 138
Views: 4907

Re: ABug NORTH User Group meeting | 19-21 JAN 2018 | MANCHESTER *BOOKING INFO*

BigEd wrote:Ah, the red keys confused (and impressed) me - this is the system previously seen on a breadboard?

Yes, he was testing parts of the circuits at a slow clock speed at previous meet-ups.

He is awaiting the space bar parts, hence why he has not populated all the keyboard keyswitches yet.

Mark
by 1024MAK
Sun Jan 21, 2018 11:59 am
Forum: upcoming and recent events & exhibitions
Topic: ABug NORTH User Group meeting | 19-21 JAN 2018 | MANCHESTER *BOOKING INFO*
Replies: 138
Views: 4907

Re: ABug NORTH User Group meeting | 19-21 JAN 2018 | MANCHESTER *BOOKING INFO*

Phil, you must have looked during the time I was correcting the picture from the Australian version! :lol:

Mark
by 1024MAK
Sun Jan 21, 2018 11:17 am
Forum: upcoming and recent events & exhibitions
Topic: ABug NORTH User Group meeting | 19-21 JAN 2018 | MANCHESTER *BOOKING INFO*
Replies: 138
Views: 4907

Re: ABug NORTH User Group meeting | 19-21 JAN 2018 | MANCHESTER *BOOKING INFO*

Here is a close up of Robert's single board 6502 system:
IMG_6390.JPG


Daniel upgrading a Master:
IMG_6387.JPG

Still plenty going on:
IMG_6386.JPG

IMG_6389.JPG

IMG_6388.JPG

Mark
by 1024MAK
Sat Jan 20, 2018 11:22 pm
Forum: upcoming and recent events & exhibitions
Topic: ABug NORTH User Group meeting | 19-21 JAN 2018 | MANCHESTER *BOOKING INFO*
Replies: 138
Views: 4907

Re: ABug NORTH User Group meeting | 19-21 JAN 2018 | MANCHESTER *BOOKING INFO*

Thanks for the photos! I recognise Steve Furber but who else do we see? And what's that single board Beeb with SCART output? And is that a very special cheese wedge? As Phil says, Steve signed one of the manuals for it (Ian / BeebMaster took a photo of the signatures in the manual, but I did not). ...
by 1024MAK
Sat Jan 20, 2018 11:39 am
Forum: upcoming and recent events & exhibitions
Topic: ABug NORTH User Group meeting | 19-21 JAN 2018 | MANCHESTER *BOOKING INFO*
Replies: 138
Views: 4907

Re: ABug NORTH User Group meeting | 19-21 JAN 2018 | MANCHESTER *BOOKING INFO*

More photos, including a small number featuring our special guests :D IMG_6314.JPG IMG_6315.JPG IMG_6316.JPG IMG_6317.JPG IMG_6318.JPG IMG_6319.JPG IMG_6320.JPG IMG_6321.JPG IMG_6322.JPG IMG_6323.JPG IMG_6324.JPG IMG_6325.JPG IMG_6326.JPG IMG_6328.JPG IMG_6329.JPG IMG_6330.JPG IMG_6331.JPG IMG_6332....
by 1024MAK
Fri Jan 19, 2018 11:59 pm
Forum: upcoming and recent events & exhibitions
Topic: ABug NORTH User Group meeting | 19-21 JAN 2018 | MANCHESTER *BOOKING INFO*
Replies: 138
Views: 4907

Re: ABug NORTH User Group meeting | 19-21 JAN 2018 | MANCHESTER *BOOKING INFO*

danielj wrote:Do we have hot air in there? Do I need to bring the hot air? Will bring eprom programmer.

d.


Err, maybe super glue... and hot air...

Mark
by 1024MAK
Fri Jan 19, 2018 10:52 pm
Forum: upcoming and recent events & exhibitions
Topic: RISC OS SouthWest Show 2018 - Saturday 24th February, 2018
Replies: 1
Views: 86

RISC OS SouthWest Show 2018 - Saturday 24th February, 2018

RISC OS SouthWest Show 2018 - Saturday 24th February, 2018

Image

Web site http://www.riscos-swshow.co.uk
by 1024MAK
Fri Jan 19, 2018 10:04 pm
Forum: upcoming and recent events & exhibitions
Topic: ABug NORTH User Group meeting | 19-21 JAN 2018 | MANCHESTER *BOOKING INFO*
Replies: 138
Views: 4907

Re: ABug NORTH User Group meeting | 19-21 JAN 2018 | MANCHESTER *BOOKING INFO*

Some photos...

IMG_6232.JPG
Roland, Kees, Phil, Phill, Matthew and Bryan with Ian hiding behind!

IMG_6233.JPG
Recreated System computer by Prime (Phill)

IMG_6230.JPG
Dave's workstation

IMG_6231.JPG
Guess who's pile this is...

IMG_6229.JPG
Matthew's table

IMG_6228.JPG
A small table of refreshments and snacks...

IMG_6227.JPG
And another :-)

Mark
by 1024MAK
Fri Jan 19, 2018 9:52 pm
Forum: upcoming and recent events & exhibitions
Topic: ABug NORTH User Group meeting | 19-21 JAN 2018 | MANCHESTER *BOOKING INFO*
Replies: 138
Views: 4907

Re: ABug NORTH User Group meeting | 19-21 JAN 2018 | MANCHESTER *BOOKING INFO*

danielj wrote:I'll be joining you all bright and early :) Let me know if there's any bits and bobs needed! :)

d.

Ian has requested some help with repairs... so bring your entire workshop!

Mark
by 1024MAK
Fri Jan 19, 2018 7:07 pm
Forum: upcoming and recent events & exhibitions
Topic: ABug NORTH User Group meeting | 19-21 JAN 2018 | MANCHESTER *BOOKING INFO*
Replies: 138
Views: 4907

Re: ABug NORTH User Group meeting | 19-21 JAN 2018 | MANCHESTER *BOOKING INFO*

Arcadian wrote:Everybody else in the Bridgewater! :)

Yes, currently plenty of room, just three of us so far...

Mark
by 1024MAK
Fri Jan 19, 2018 3:42 pm
Forum: hardware
Topic: Large project box
Replies: 5
Views: 253

Re: Large project box

If you want a plastic rectangular box with a flat top, search for 19 inch rack plastic boxes.

E.g. On eBay "Black 19 Inch ABS Plastic Rack Mount Case Box Enclosure"

Mark
by 1024MAK
Thu Jan 18, 2018 10:40 pm
Forum: upcoming and recent events & exhibitions
Topic: ABug NORTH User Group meeting | 19-21 JAN 2018 | MANCHESTER *BOOKING INFO*
Replies: 138
Views: 4907

Re: ABug NORTH User Group meeting | 19-21 JAN 2018 | MANCHESTER *BOOKING INFO*

Why can you never find what you want when your time is limited... :shock: :(

Mark
by 1024MAK
Thu Jan 18, 2018 9:47 pm
Forum: other vintage computer hardware, software and games
Topic: Reading EPROMS
Replies: 10
Views: 283

Re: Reading EPROMS

/OE (negative logic output enable) turns on the three state drives on the output pins, while /CE or /CS (negative logic chip enable or chip select) brings it out of "standby" mode and tells it to read it's memory. So normally /CE or /CS is connected to address decoder logic and /OE is conn...
by 1024MAK
Thu Jan 18, 2018 4:08 pm
Forum: other vintage computer hardware, software and games
Topic: Reading EPROMS
Replies: 10
Views: 283

Re: Reading EPROMS

The data area of an EPROM is actually analog. Comparators actually decide if each memory cell is a zero or a one based on the voltage from the cell. The rest of the circuitry is either NMOS or CMOS logic circuits, with the CPU interface designed to be compatible with 5V TTL logic (for the smaller/ol...

Go to advanced search