Search found 5352 matches

by MartinB
Mon Nov 23, 2020 8:32 pm
Forum: 8-bit acorn hardware
Topic: Sideways Ram
Replies: 9
Views: 269

Re: Sideways Ram

That looks better than my shambles - I never claimed to be a software ninja.... :lol:
by MartinB
Mon Nov 23, 2020 8:21 pm
Forum: 8-bit acorn hardware
Topic: Sideways Ram
Replies: 9
Views: 269

Re: Sideways Ram

Becky wrote:Edit: Penny dropped about the EEPROM. that sounds interesting. Can that be written to inside the machine?

There are some utilities here for in-machine EEPROM writing and management - I don't know if there are any others around?
by MartinB
Fri Nov 20, 2020 7:43 pm
Forum: 8-bit acorn hardware
Topic: BBC B, Issue 7 board - cooling
Replies: 7
Views: 242

Re: BBC B, Issue 7 board - cooling

Well...shoot. I thought I was coming to the end of my hardware hacks. Thanks a lot, Martin. No worries Jason 8) btw - the manual only describes connecting I2C modules & gadgets externally but in the case of the cheap’n’cheerful RTC & Temp module, which is something I and many others have as a perma...
by MartinB
Fri Nov 20, 2020 10:54 am
Forum: 8-bit acorn hardware
Topic: BBC B, Issue 7 board - cooling
Replies: 7
Views: 242

Re: BBC B, Issue 7 board - cooling

For less than a fiver and an hour’s work, your boot and <Break> screen can look like this......

B4582763-4E13-4C64-B544-5F989EB2A82F.jpeg
B4582763-4E13-4C64-B544-5F989EB2A82F.jpeg (10.34 KiB) Viewed 219 times

....where the temperature display reflects wherever you choose to mount a miniature RTC & Temperature module inside your Beeb.


Clicky here for details.
by MartinB
Thu Nov 19, 2020 6:56 am
Forum: 8-bit acorn hardware
Topic: EPROM and EEPROM Compatibility
Replies: 29
Views: 575

Re: EPROM and EEPROM Compatibility

Back to the EEPROM chat, here's a quick video of what happens with an AT28C256 attached to the system. Corruption ahoy! You need to fit a write-protect switch to Pin 27 of the 28C256 such that this pin is tied high (Vcc) for normal use after writing. Here’s a snip from the ‘Holy Grail’ thread which...
by MartinB
Mon Nov 09, 2020 7:22 pm
Forum: 8-bit acorn hardware
Topic: Issue 3 in a Viglen Case - not working -
Replies: 12
Views: 340

Re: Issue 3 in a Viglen Case - not working -

When you get new OS and Basic roms, you can attempt to fire up your machine - you don't need an ADC chip unless you want to use joysticks. However, one additional residual from the shoddy ATPL removal is likely to be incorrect motherboard links. The pic below shows the link specifics for fitting an ...
by MartinB
Mon Nov 09, 2020 6:36 pm
Forum: 8-bit acorn hardware
Topic: Issue 3 in a Viglen Case - not working -
Replies: 12
Views: 340

Re: Issue 3 in a Viglen Case - not working -

Missing OS and Basic roms is very often due to someone removing a previously fitted rom expansion board (e.g. ATPL) to which the missing roms will have been transferred on initial fitting. If the removal is subsequently done in ignorance of the technicalities, the devices sadly become parted from th...
by MartinB
Sun Nov 01, 2020 9:11 pm
Forum: 8-bit acorn hardware
Topic: I designed a UPURS Adapter PCB - yes, really
Replies: 6
Views: 290

Re: I designed a UPURS Adapter PCB - yes, really

Ooh, missed this! Very nice job Ed =D> :)

(I cut my pcb-design teeth on Beeb stuff after joining the forum too as it happens - on mine & Sarah W’s BeebSID project.)
by MartinB
Sat Oct 31, 2020 11:36 pm
Forum: 8-bit acorn hardware
Topic: Upurs rom
Replies: 6
Views: 325

Re: Upurs rom

Hi - yes, the Watford 62 file catalogue would confuse the F option because the latter still uses the disc-written catalogue parameters to establish the actual maximum formatted capacity (as opposed to the used quantity) of the source disc and normally, for a standard Acorn-compatible DFS disc, the c...
by MartinB
Tue Oct 27, 2020 1:33 pm
Forum: general
Topic: Today I received.....
Replies: 6056
Views: 640961

Re: Today I received.....

Simply every shade of awesome! =D> 8)
by MartinB
Mon Oct 26, 2020 10:12 pm
Forum: 8-bit acorn hardware
Topic: Upurs rom
Replies: 6
Views: 325

Re: Upurs rom

Since I think you're using a superseded version of UPURS (though all of the released versions work just fine), here's a copy of the 5.1 release post from the UPURS home thread..... UPURS 5.1 Banner.jpg The attached zip contains the following UPURS v5.1 update files : UPURS 5.1R 16k binary rom image ...
by MartinB
Mon Oct 26, 2020 8:50 pm
Forum: 8-bit acorn hardware
Topic: Upurs rom
Replies: 6
Views: 325

Re: Upurs rom

Ok, the flashing star comes from Commstar and it seems that the UPURS banner is partially overwriting the Commstar title but leaving the flashing star. Don't worry about that for now, I think this got fixed in UPURS 5.1 and I think you're perhaps using an earlier version? My connection is working on...
by MartinB
Mon Oct 26, 2020 6:07 pm
Forum: 8-bit acorn hardware
Topic: Upurs rom
Replies: 6
Views: 325

Re: Upurs rom

Hi - I'm not sure what the flashing star is, how have you listed the roms to see this? Just *HELP? Assuming the UPURS rom is a valid image & device, there are a number of 'Star' commands available which you should be able to see with *HELP UPURS and in case you have misplaced it, the manual is attac...
by MartinB
Wed Oct 07, 2020 12:47 pm
Forum: 8-bit acorn software: other
Topic: Help, I want to REPEAT:UNTIL 0=?F%
Replies: 17
Views: 2308

Re: Help, I want to REPEAT:UNTIL 0=?F%

If you are messing with system memory and/or devices therein and if your F% location does take a finite time to become zero such that the Basic program is largely looping at line 99, then a misguided interrupt-driven poke or illegal action that erroneously disrupts Basic’s operating framework could...
by MartinB
Tue Oct 06, 2020 10:35 pm
Forum: 8-bit acorn hardware
Topic: Weird behaviour with simple BASIC program
Replies: 40
Views: 1548

Re: Weird behaviour with simple BASIC program

The 1N4148 D13 non-zener diode as shown in the Beeb circuit diagram is intended to suppress the back emf at source (at the relay) such that in addition to protecting the transistor and LED, it will also minimise perturbations that may adversely affect anything else sitting nearby on the same 5v rail...
by MartinB
Tue Oct 06, 2020 9:57 pm
Forum: 8-bit acorn software: other
Topic: Help, I want to REPEAT:UNTIL 0=?F%
Replies: 17
Views: 2308

Re: Help, I want to REPEAT:UNTIL 0=?F%

I assume this is a Model B? I just happened to be real Beeb tinkering so I’ve tried everything in immediate mode and program-borne to make it fail with a Syntax error but I really can’t :? (....without genuinely creating a syntax mistake) If you are messing with system memory and/or devices therein ...
by MartinB
Fri Oct 02, 2020 7:38 pm
Forum: 8-bit acorn hardware
Topic: Weird behaviour with simple BASIC program
Replies: 40
Views: 1548

Re: Weird behaviour with simple BASIC program

You should always mount such protection diodes as close - physically - to the relay coil as possible to ensure maximum effectiveness and to minimise EMC. If you solder it on the back of the board across the two relay coil soldered connections, you won't be 'spoiling' anything. Locating it remotely i...
by MartinB
Fri Oct 02, 2020 6:46 am
Forum: 8-bit acorn hardware
Topic: Weird behaviour with simple BASIC program
Replies: 40
Views: 1548

Re: Weird behaviour with simple BASIC program

Good news in a way. I was confident that this had all the hallmarks of a relay diode issue but I’d missed the nuance of your machine being an Issue 3 where, as you have discovered, the diode is present but is not optimally positioned to suppress relay-induced back emf. It will be interesting to conf...
by MartinB
Fri Oct 02, 2020 6:20 am
Forum: 8-bit acorn software: other
Topic: Writing ssd disk images on a BBC Master
Replies: 7
Views: 504

Re: Writing ssd disk images on a BBC Master

I think there might be a bit of a Catch-22 here...in order to use the program which will write an SSD image file to a floppy disc, you have to have a program which will write the SSD image file with the program on it to a floppy disc in order to use it to write the SSD image file to a floppy disc.....
by MartinB
Thu Oct 01, 2020 9:35 am
Forum: new projects in development: games
Topic: Elementum - new Elk/Beeb platformer
Replies: 135
Views: 6140

Re: New Elk/Beeb platformer - playable demo

....my interests lie in only kit that existed back in the day or modern re-creations of said kit. For example awhile ago I built myself a couple of those userport micro-sd card storage thingies but I gave up on them and went back to floppies as the magic was missing. Yay! There are two of us! =D> =...
by MartinB
Tue Sep 29, 2020 4:46 pm
Forum: 8-bit acorn software: other
Topic: Writing ssd disk images on a BBC Master
Replies: 7
Views: 504

Re: Writing ssd disk images on a BBC Master

If you mean specifically DFS ssd/dsd images (as opposed to AFDS images which you also mentioned) and if you are equipped to make a cable, UPURS is designed for this specific purpose....

https://www.retro-kit.co.uk/UPURS/
by MartinB
Mon Sep 28, 2020 4:49 pm
Forum: 8-bit acorn hardware
Topic: Weird behaviour with simple BASIC program
Replies: 40
Views: 1548

Re: Weird behaviour with simple BASIC program

At whatever point you declare success and press Escape, but before you switch off, try one of your *MOTOR ditties again to confirm that you still have the (possible) relay-induced issue. If it doesn't fail, before you further celebrate, switch off and try again when the Beeb has fully cooled down.
by MartinB
Mon Sep 28, 2020 3:43 pm
Forum: 8-bit acorn hardware
Topic: Weird behaviour with simple BASIC program
Replies: 40
Views: 1548

Re: Weird behaviour with simple BASIC program

Thanks for your comprehensive analysis!! I have to say it sounds about right to me. If the diode were bad (or has a dry joint) then there would be a big fat back EMF from the relay which could kill the LED. Also, that big fat back EMF could well cause a big hiccup on the power rails sufficient to c...
by MartinB
Mon Sep 28, 2020 6:30 am
Forum: 8-bit acorn hardware
Topic: Weird behaviour with simple BASIC program
Replies: 40
Views: 1548

Re: Weird behaviour with simple BASIC program

The relay has a diode, D13, across the coil to suppress back-emf high voltage spikes from the latter during relay operation. If the diode has degraded or failed or is poorly connected, the 5v rail could experience transient perturbations which might upset other aspects of the machine. Just a thought...
by MartinB
Fri Sep 25, 2020 6:41 am
Forum: wanted
Topic: Solidisk RTC
Replies: 2
Views: 409

Re: Solidisk RTC

Do you specifically want a Solidisk RTC board or are you just assuming that’s the only way to a Beeb RTC? In case it’s just the generic RTC capability you’re after, you can add one very cheaply using I2C. Clicky here if interested..... :arrow:
by MartinB
Tue Sep 22, 2020 8:18 pm
Forum: programming
Topic: Loading files at &400
Replies: 7
Views: 413

Re: Loading files at &400

That should be fine as long as BASIC is ‘off’ and not being used. Can you temporarily load the data somewhere else, say &0900-&0AFF or higher up in memory (but below screen mem) to see if it is a location problem?
by MartinB
Wed Sep 16, 2020 6:58 am
Forum: wanted
Topic: (Found) Wanted - EdWord ROM
Replies: 5
Views: 267

Re: Wanted - EdWord ROM

Dave wrote:Can you work out what the C (and also the E) stand for now ... boyo? ;)

Chinese and Emakhuwa ? :-k


(I can’t believe how difficult it is to find a language other than English that begins with ‘E’...... :lol: )
by MartinB
Tue Sep 15, 2020 10:20 pm
Forum: wanted
Topic: (Found) Wanted - EdWord ROM
Replies: 5
Views: 267

Re: Wanted - EdWord ROM

For eprom blowing - no idea of the differences between the versions.

Just added more, maybe the ‘E’ versions are Electron?

.
by MartinB
Tue Sep 15, 2020 5:38 pm
Forum: 8-bit acorn hardware
Topic: Following in the footsteps...
Replies: 8
Views: 607

Re: Following in the footsteps...

Sounds fascinating Stephen, keep us posted! :) One minor point, I have subsequently discovered that because the MOS obviously shares the same system 6522 lines as I have used for my I2C, if you mess with keyboard during certain I2C accesses, you can corrupt a transfer. I can’t ‘break’ anything as su...
by MartinB
Mon Sep 14, 2020 11:20 pm
Forum: for sale / freebies
Topic: Ribbon Cables
Replies: 12
Views: 611

Re: Ribbon Cables

I guessed so because I’ve had that particular feature forever - back in the day and now, it’s still an essential on all my floppy drive pairs. It’s particularly useful for 35/525 combo units because I tend to use 35s for everyday stuff due to their robustness but still have lots of bootable 525s kno...

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