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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 ...

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...

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...

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.

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...

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 ...

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).

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...

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...

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...

The BBC Microcomputer Service Manual explains from page 12 onwards.

http://chrisacorns.computinghistory.org ... n/Manuals/

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...

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.

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.

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 .

If something has been spilt on your keyboard (coffee or Coke) then wash the keycaps in water & mild detergent (dish soap).

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...

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).

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...

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...

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

https://youtu.be/tfw3w8DG2S4

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...

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...

Bump.

Item prices still the same but postage is higher now the RM keeps putting its prices up twice a year :/

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.

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...

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...

Just try it:

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

https://www.ebay.co.uk/itm/Box-of-10-Fa ... SwWplfSjyN

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...