Search found 1313 matches

by cmorley
Thu Oct 15, 2020 9:23 am
Forum: 8-bit acorn hardware
Topic: BBC B ROM Order
Replies: 21
Views: 397

Re: BBC B ROM Order

Language ROM is a bit of a misnomer on the beeb. AFAIK it simply means a ROM with a language entry point... the active "language" owns the language workspace. It need not be a programming language. So word processor, debug tool, paint program - you name it, you can write it as a language. EXMON has ...
by cmorley
Wed Oct 14, 2020 4:23 pm
Forum: 8-bit acorn hardware
Topic: BBC B ROM Order
Replies: 21
Views: 397

Re: BBC B ROM Order

Bobbi wrote:
Wed Oct 14, 2020 3:03 pm
although the idea of having RAM in the highest numbered slot is also interesting.
My SWRAM provides RAM in the 2 lower priority banks of the 4 for each socket...
by cmorley
Wed Oct 14, 2020 7:36 am
Forum: 8-bit acorn hardware
Topic: BBC B ROM Order
Replies: 21
Views: 397

Re: BBC B ROM Order

I am thinking I should move BASIC to the slot when the MMFS is currently, so it is always the highest priority. Is there a reason why BASIC is not in the easterly socket by default? Any other hints on how best to configure things? BASIC is often in the most easterly socket. With the SWRAM and EEPRO...
by cmorley
Sun Oct 11, 2020 8:50 pm
Forum: 8-bit acorn hardware
Topic: Minimal Tube 6502decode bus snoop with FTDI USB
Replies: 74
Views: 6549

Re: Minimal Tube 6502decode bus snoop with FTDI USB

AS hoglet pointed out the bus snoop won't work on a Master because the Tube is buffered so is isolated from the normal CPU activity. Serial comms does but bus snoop is model A/B only.
by cmorley
Fri Oct 09, 2020 5:30 am
Forum: 8-bit acorn hardware
Topic: Watford Electronics Co-Pro Box Power Supply
Replies: 2
Views: 156

Re: Watford Electronics Co-Pro Box Power Supply

From the picture it is just a regular 50Hz transformer into a bridge rectifier & smoothing capacitor. This feeds the 7805. A standard old school linear PSU. You could source and fit the parts to make one if you want a little project... or you could remove/disconnect the 7805 and feed it with 5v from...
by cmorley
Fri Oct 09, 2020 5:13 am
Forum: 8-bit acorn hardware
Topic: Technomatic Newbie Eprom Programmer Saga
Replies: 5
Views: 173

Re: Technomatic Newbie Eprom Programmer Saga

got a batch of 27128 eproms new from overseas I don't know about using that programmer but your EPROM in the photo is not new, it is remarked. ST did not make EPROMs with that size die at that capacity in 2014... I thought they had stopped making EPROMs altogether in the 00s. That being said apart ...
by cmorley
Mon Oct 05, 2020 6:40 pm
Forum: 8-bit acorn hardware
Topic: SDC timing constraints question
Replies: 11
Views: 290

Re: SDC timing constraints question

Isn't the fast model for checking the corner case that things might happen too quickly with the combination of fastest silicon and most favourable temperature? I'd have thought you'd be interested in the slow model at the moment to ensure things happen in enough time for the setup (and recovery).
by cmorley
Mon Oct 05, 2020 6:29 pm
Forum: 8-bit acorn hardware
Topic: SDC timing constraints question
Replies: 11
Views: 290

Re: SDC timing constraints question

Is propogating clock enables widly considered good form? If there is no dedicated "fast path" mechanism (or resource available) then you're going to suffer horrendous skew as the clock enable propogates across the fabric. Seems like a lot of work for the fitter to guarantee the setup/hold on the clo...
by cmorley
Mon Oct 05, 2020 3:29 pm
Forum: 8-bit acorn hardware
Topic: SDC timing constraints question
Replies: 11
Views: 290

Re: SDC timing constraints question

My experience of multicyle paths is for source synchronous interfaces which are a complete head exploder. A gui tool where you can draw your external paths and it sorts out the SDC for you would be ace! It sounds like what you have done is one way to skin the cat but if you have slow model timing vi...
by cmorley
Mon Oct 05, 2020 12:04 pm
Forum: 8-bit acorn hardware
Topic: SDC timing constraints question
Replies: 11
Views: 290

Re: SDC timing constraints question

I've used multicycle constraints before but I don't know what the -thru is supposed to do. I read the Altera Timequest manual page on it and am still none the wiser. I don't really understand what you are trying to constrain so can't be much help I'm afraid. Are you trying to reclock to 16MHz or clo...
by cmorley
Sat Oct 03, 2020 5:48 pm
Forum: 8-bit acorn hardware
Topic: SOLVED - Memory Refresh problem/failure
Replies: 40
Views: 974

Re: Memory Refresh

Was this in a graphics mode? I think you can see the counting in A3-6. The values are the value preceeding the falling RAS on every odd RAS (the even RAS is the CPU memory access). A0-2 would then be from the character line so won't change on the same scanline. You really need a faster sampling logi...
by cmorley
Sat Oct 03, 2020 3:27 pm
Forum: 8-bit acorn hardware
Topic: SOLVED - Memory Refresh problem/failure
Replies: 40
Views: 974

Re: Memory Refresh

In mode 7 yes, MA0-MA6.

Graphics modes use the RA0-2, MA0-3.

You really need to look on the DRAM inputs though A0-6 (pins 5,7,6,12,11,10,13) when RAS (pin 4) goes low.
by cmorley
Sat Oct 03, 2020 3:02 pm
Forum: 8-bit acorn hardware
Topic: SOLVED - Memory Refresh problem/failure
Replies: 40
Views: 974

Re: Memory Refresh

It is done by way of the video output. As the 6845 generates memory addresses for graphics/Teletext mode every ROW in RAM is touched with a read. This is sufficient to refresh DRAM.

So as long as the 6845 is generating sensible screen addresses then main memory will be refreshed.
by cmorley
Fri Oct 02, 2020 10:55 pm
Forum: development tools
Topic: vbcc optimizing C compiler for 6502 now supports bbc
Replies: 6
Views: 224

Re: vbcc optimizing C compiler for 6502 now supports bbc

Do you have the instructions to integrate it into a local copy of compiler explorer properly?

I managed to get it to run in CE but only by using bin/vbcc6502 not the driver bin/vc. With bin/vc I got a "no config file" error :| .
by cmorley
Thu Oct 01, 2020 10:22 am
Forum: 8-bit acorn hardware
Topic: Any ideas?
Replies: 18
Views: 505

Re: Any ideas?

If something has been spilt on your keyboard (coffee or Coke) then wash the keycaps in water & mild detergent (dish soap).
by cmorley
Wed Sep 30, 2020 6:40 pm
Forum: 8-bit acorn hardware
Topic: Any ideas?
Replies: 18
Views: 505

Re: Any ideas?

Colday wrote:
Wed Sep 30, 2020 12:23 pm
I reckon this will work a treat.
Yey! It's solvents like Acetone you need to be really careful with plastics...
by cmorley
Wed Sep 30, 2020 5:29 am
Forum: 8-bit acorn hardware
Topic: Any ideas?
Replies: 18
Views: 505

Re: Any ideas?

If they have been covered in oil which detergent won't touch then you'll need a solvent which will dissolve oil. IPA is not one.

Petrol, trichlorethane (banned) or brake cleaner (without trich).
by cmorley
Sun Sep 27, 2020 9:26 am
Forum: 8-bit acorn hardware
Topic: 6522 differences?
Replies: 10
Views: 289

Re: 6522 differences?

Mark is good option for genuine Beeb spares. I think his prices are very reasonable for the fast shipping and tested/known good status. It'd be OK buying from China if the didn't relabel the parts & you knew what you were getting... patina is fine on recalimed spares! But 1MHz parts labelled as 2MHz...
by cmorley
Thu Sep 24, 2020 8:46 am
Forum: 8-bit acorn hardware
Topic: Following in the footsteps...
Replies: 8
Views: 526

Re: Following in the footsteps...

To melt a beeb power wire that has to have been way higher current than what a scope would pull. I connect my scope regularly between ground and +5v without a problem. The model B's PSU ground is earth referenced. The ground on a scope is also earth referenced. If you misconnect the scope ground to...
by cmorley
Mon Sep 21, 2020 8:06 am
Forum: general
Topic: Remarkable videos recently posted on Youtube
Replies: 352
Views: 53345

Re: Remarkable videos recently posted on Youtube

A very interesting video on grounding and bypassing in power electronics.

https://youtu.be/tfw3w8DG2S4
by cmorley
Thu Sep 17, 2020 6:26 pm
Forum: 8-bit acorn hardware
Topic: [SOLVED] Connections to chips - e.g. for large eprom boards
Replies: 12
Views: 370

Re: Connections to chips - e.g. for large eprom boards

I got one of the BooBip eprom adaptors for >32k eproms and it came with those "grabber clips" that are usually used for oscilloscopes and the like. I see a few modifications done with these clips, where connections to existing chips are needed. I provide clips because they are easy to use for non-e...
by cmorley
Sat Sep 12, 2020 9:16 pm
Forum: programming
Topic: Zalaga
Replies: 5
Views: 434

Re: Zalaga

Searching this site there seem to be issues in the past with the game using 65C02 op codes, but my beeb has a 65C02, but the beebem setup I used was bog standard. I think Zalaga uses 6502 illegal opcodes & therefore (unpatched) doesn't work on a 65C02. I believe it doesn't run on a Master for the s...
by cmorley
Thu Sep 10, 2020 9:58 am
Forum: for sale / freebies
Topic: New Model B upgrades EEPROM, SRAM, adapters etc (BooBip)
Replies: 11
Views: 2284

Re: New Model B upgrades EEPROM, SRAM, adapters etc (BooBip)

Bump.

Item prices still the same but postage is higher now the RM keeps putting its prices up twice a year :/
by cmorley
Thu Sep 10, 2020 9:55 am
Forum: 8-bit acorn hardware
Topic: Recommended BBC Model B upgrades
Replies: 50
Views: 1278

Re: Recommended BBC Model B upgrades

flaxcottage wrote:
Tue Sep 08, 2020 9:19 am
The BooBip SWR and EEPROM boards are a 'must' for a Beeb.
For newer forum members' information I make these. There is a sales thread on this forum for them.. it has probably sunk a bit so I could bump it.
by cmorley
Tue Sep 08, 2020 11:15 am
Forum: 8-bit acorn hardware
Topic: Recommended BBC Model B upgrades
Replies: 50
Views: 1278

Re: Recommended BBC Model B upgrades

I do like the Gotek flash floppys, but for use as a 'jukebox' is there any significant advantage over a cheap turboSD module? Depends what you want to do... getting floppy images onto and off the beeb.mmb on an SD card is a PITA. Copying a floppy image to a USB stick is pretty simple. If you want t...
by cmorley
Sun Sep 06, 2020 7:30 am
Forum: general
Topic: BBC Micro Books
Replies: 9
Views: 585

Re: BBC Micro Books

Hi, The original "BBC Microcomputer User Guide" which packed in box with the system I believe is actually a really good manual with moderate technical detail and an extensive BASIC language reference. "The Advanced User Guide"/"The New Advanced User Guide" are a great reference for low level underst...
by cmorley
Wed Sep 02, 2020 9:47 pm
Forum: programming
Topic: Two DEFPROCs, one ENDPROC?
Replies: 8
Views: 446

Re: Two DEFPROCs, one ENDPROC?

Just try it:

Code: Select all

   10PROCA
   20PROCB
   30END
   40DEFPROCA
   50PRINT"a";
   60DEFPROCB
   70PRINT"b"
   80ENDPROC
by cmorley
Sun Aug 30, 2020 12:09 pm
Forum: for sale / freebies
Topic: Worth Taking a Look At
Replies: 2884
Views: 343940

Re: Worth Taking a Look At

On the seller's other items he has relisted the hard sector floppies.

https://www.ebay.co.uk/itm/Box-of-10-Fa ... SwWplfSjyN
by cmorley
Sun Aug 30, 2020 8:24 am
Forum: general
Topic: That was almost a mistake!
Replies: 15
Views: 485

Re: That was almost a mistake!

I'm tempted to put a supercap in my Master... For if it goes flat, I'll just *BUILD a script on a floppy (gotek SSD image) to run all the *CONFIGURE commands I like on my Master. CMOS reset... DFS... and one *EXEC later I'll be back running. No lid off to swap cells. No battery leakage worry ever ag...

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