Search found 1548 matches

by BigEd
Sun Dec 24, 2017 10:32 pm
Forum: software & utilities for the pc, mac or unix
Topic: How to convert tape to UEF
Replies: 34
Views: 905

Re: How to convert tape to UEF

Here's a screenshot of four data blocks, in between five solid tones. There's a bit of a tape dropout in the middle of the fourth block, about 11.7 sec timestamp - you can see the high and low tone bars both vanish. It is easier to see the dropout by looking at the 'waveform db' view, but easier to ...
by BigEd
Sun Dec 24, 2017 10:28 pm
Forum: software & utilities for the pc, mac or unix
Topic: How to convert tape to UEF
Replies: 34
Views: 905

Re: How to convert tape to UEF

(No, cancel that: stay with linear. Perhaps change the max frequency to 4000. What you see is one solid horizontal bar for the inter-block tone, and then the data blocks are more of a mush but with two horizontal bars broadly visible.)
by BigEd
Sun Dec 24, 2017 9:44 pm
Forum: software & utilities for the pc, mac or unix
Topic: How to convert tape to UEF
Replies: 34
Views: 905

Re: How to convert tape to UEF

I think I'd just play around - you're looking for any setting which makes the data blocks stand out. Start with the defaults, but perhaps change linear to logarithmic.
by BigEd
Sun Dec 24, 2017 8:02 pm
Forum: software & utilities for the pc, mac or unix
Topic: How to convert tape to UEF
Replies: 34
Views: 905

Re: How to convert tape to UEF

Audacity has a spectrum view for waveforms, which is a good way to see (and count) data blocks. Could be useful if you're setting out to splice things from one waveform to another.

https://manual.audacityteam.org/man/spe ... _view.html
by BigEd
Sun Dec 24, 2017 5:49 pm
Forum: emulators
Topic: Mac BeebEm4 - Decimal Mode and the System Clock
Replies: 2
Views: 188

Re: Mac BeebEm4 - Decimal Mode and the System Clock

The 65c02 - unlike the 6502 - clears decimal mode when an interrupt is taken. So code for an interrupt handler which is certainly running on a 65c02 need not CLD, whereas code for a general 6502 must do a CLD if it is going to use ADC or SBC. Of course, when the RTI comes there's an implicit PLP, so...
by BigEd
Sat Dec 23, 2017 3:25 pm
Forum: bbcmicro.co.uk
Topic: Games that don't work in jsbeeb
Replies: 25
Views: 2235

Re: Games that don't work in jsbeeb

Those URLs failed for me too, but on a laptop, using Chrome.
by BigEd
Wed Dec 20, 2017 3:23 pm
Forum: general
Topic: Acorn Internal Development Doc (early 80s)
Replies: 4
Views: 380

Re: Acorn Internal Development Doc (early 80s)

Ah, thanks.
by BigEd
Wed Dec 20, 2017 11:46 am
Forum: general
Topic: Acorn Internal Development Doc (early 80s)
Replies: 4
Views: 380

Re: Acorn Internal Development Doc (early 80s)

That would be an interesting read! Did the 'faults' mechanism fall away? I'm aware of 'events' but not 'faults' - although we do have 'errors.'
by BigEd
Wed Dec 20, 2017 9:52 am
Forum: hardware
Topic: Pi-based Co-Pro on the cheap - 100MHz 6502 for £10? (now 274MHz)
Replies: 1018
Views: 79094

Re: Pi-based Co-Pro on the cheap - 100MHz 6502 for £10? (now 274MHz)

It looks like the Pi takes up to 150ns to respond to changes in the various signals, and is just barely done by the time /TUBE goes high again. So to be safe, I should have the CPLD drop the bus whenever /TUBE=0 and RnW=1, and not drive it again until the following rising clock edge. That should be...
by BigEd
Wed Dec 20, 2017 9:49 am
Forum: hardware
Topic: Pi-based Co-Pro on the cheap - 100MHz 6502 for £10? (now 274MHz)
Replies: 1018
Views: 79094

Re: Pi-based Co-Pro on the cheap - 100MHz 6502 for £10? (now 274MHz)

Excellent result - glad I could help (a little).

That's a very interesting multi-purpose board - worth a promotion in its own thread?
by BigEd
Wed Dec 20, 2017 8:47 am
Forum: hardware
Topic: Pi-based Co-Pro on the cheap - 100MHz 6502 for £10? (now 274MHz)
Replies: 1018
Views: 79094

Re: Pi-based Co-Pro on the cheap - 100MHz 6502 for £10? (now 274MHz)

It might be helpful to distinguish PiTubeDirect, as a piece of software running on a Pi, from a level shifter, which connects the 3V Pi to the 5V Beeb. That's because the usual and common design of level shifter has two parts: a control lines part which is (mostly?) unidirectional towards the Pi, an...
by BigEd
Tue Dec 19, 2017 6:55 pm
Forum: emulators
Topic: Model A, OS 0.1 and disc interfaces
Replies: 10
Views: 509

Re: Model A, OS 0.1 and disc interfaces

I vaguely recall that OS 0.1 couldn't support disk, and it was almost a violation of the advertising or trading rules at the time. Which is to say, perhaps Acorn should have offered a free upgrade to the OS, but they didn't. I wrote to them at the time, with a poorly-worded letter which failed to ge...
by BigEd
Tue Dec 19, 2017 4:42 pm
Forum: bbcmicro.co.uk
Topic: Attic Bug in SameGame: Can't "choose your venue"
Replies: 2
Views: 149

Attic Bug in SameGame: Can't "choose your venue"

I can't get started on this game - am I missing a trick? The van just drives at full speed past all the houses. In fact there's a very very brief flash of an instruction screen just before that. Perhaps it thinks there's a key stuck down...

http://bbcmicro.co.uk/game.php?id=1891
by BigEd
Tue Dec 19, 2017 4:24 pm
Forum: general
Topic: Today ZAP museum received....
Replies: 52
Views: 2785

Re: Today ZAP museum received....

Paraphrasing: "Opening early in 2019, in Noyon, an hour north of Paris, 2000 square yards of floor space, devoted to retro museum, retro meetups, retro studios, retro parties, and other educational and maker purposes."

That's twice as big as the Cambridge museum - which is big!
by BigEd
Tue Dec 19, 2017 3:42 pm
Forum: hardware
Topic: how to do ? raspberry pi 2 and beeb b lost it
Replies: 57
Views: 1062

Re: how to do ? raspberry pi 2 and beeb b lost it

The only difference with a slow card, I think, is that you might need to Break or Control-Break after you power on.
by BigEd
Tue Dec 19, 2017 9:27 am
Forum: stardot.org.uk
Topic: private messages
Replies: 12
Views: 386

Re: private messages

1024MAK wrote:Can anyone beat me for having a message in my outbox for six years! :lol:

Mark

Kind of - on another forum I have an outbox message from Feb 2009. The odd thing is, the recipient has definitely logged in and used the forum since then. Perhaps they just know they don't want to hear from me.
by BigEd
Mon Dec 18, 2017 11:44 am
Forum: hardware
Topic: Mounting prototypes
Replies: 10
Views: 353

Re: Mounting prototypes

I just put a sheet of paper in as insulation... it might depend a bit on whether you intend to keep moving the machine around.
by BigEd
Sun Dec 17, 2017 5:08 pm
Forum: hardware
Topic: how to do ? raspberry pi 2 and beeb b lost it
Replies: 57
Views: 1062

Re: how to do ? raspberry pi 2 and beeb b lost it

I wrote some notes on things you can do with the PiTubeDirect here:
https://github.com/hoglet67/PiTubeDirec ... CoPro-core
by BigEd
Fri Dec 15, 2017 9:45 pm
Forum: archive requests
Topic: BOS ROM for PMS B2P
Replies: 13
Views: 682

Re: BOS ROM for PMS B2P

So compact! So minimal! Thanks for the photos.
by BigEd
Fri Dec 15, 2017 3:55 pm
Forum: hardware
Topic: BBC Master screen interference PiTube direct
Replies: 55
Views: 1198

Re: BBC Master screen interference PiTube direct

Ah - so do all your internal adapters have inline resistors Kjell? That would much reduce the current from contention and also shift the net voltage. At which point, whether or not the noise is visible will depend on the input thresholds of the video ULA (probably) - which might vary from part to pa...
by BigEd
Fri Dec 15, 2017 2:56 pm
Forum: hardware
Topic: BBC Master screen interference PiTube direct
Replies: 55
Views: 1198

Re: BBC Master screen interference PiTube direct

Wouldn't want to downplay the warning, but the potential damage is only a hypothesis - better safe than sorry. We hadn't realised, Dave and I, that neither of us had ever hooked up our various level shifter options to the internal tube port of the Master. (We don't know what testing Kjell might have...
by BigEd
Fri Dec 15, 2017 7:54 am
Forum: off-topic
Topic: WinPC + Avast help
Replies: 7
Views: 267

Re: WinPC + Avast help

It's been a while since I used Windows, but last I did, the only sensible choice for anti-virus was Microsoft's own.
by BigEd
Thu Dec 14, 2017 11:57 am
Forum: archive requests
Topic: BOS ROM for PMS B2P
Replies: 13
Views: 682

Re: BOS ROM for PMS B2P

Pernod wrote:Does anyone have any theories on how the 65C02 boots without a ROM present on the board?

You've got me interested now!
by BigEd
Thu Dec 14, 2017 8:51 am
Forum: hardware
Topic: Acorn's Second Processors and the Tube - what, and why
Replies: 11
Views: 795

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

I do recommend following RobC's lead if you'd like to use a high level language to implement something which uses today's extra-fast second processors. I should have mentioned also, that there were a number of dual-Z80 designs back in the day where one of them handles the floppy drive, and Commodore...
by BigEd
Wed Dec 13, 2017 9:22 pm
Forum: hardware
Topic: BBC Master screen interference PiTube direct
Replies: 55
Views: 1198

Re: BBC Master screen interference PiTube direct

(Does this work too:

Code: Select all

10 MODE 0
20 GCOL 0,129
30 CLG
40 GOTO 40
?)
by BigEd
Wed Dec 13, 2017 8:08 pm
Forum: hardware
Topic: MMFS Development and Support
Replies: 729
Views: 37158

Re: MMFS Development and Support

Does this second processor connect to the Beeb's Tube connector, or to some other port? Does it have a Tube chip in it? It sounds like it doesn't.
by BigEd
Wed Dec 13, 2017 7:46 pm
Forum: hardware
Topic: BBC Master screen interference PiTube direct
Replies: 55
Views: 1198

Re: BBC Master screen interference PiTube direct

(No, sorry, I don't have an internal level shifter. I suppose we could rig up some cabling to use an external level shifter on the internal interface?)
by BigEd
Wed Dec 13, 2017 2:01 pm
Forum: hardware
Topic: BBC Master screen interference PiTube direct
Replies: 55
Views: 1198

Re: BBC Master screen interference PiTube direct

Might be worth trying independent power, for those who see the video trouble.

I'd not take the audio breakthrough as too big a clue, as I hear audio noise too on machines which run fine. I think the sound amplifier is very good at amplifying noise!
by BigEd
Wed Dec 13, 2017 1:20 pm
Forum: hardware
Topic: BBC Master screen interference PiTube direct
Replies: 55
Views: 1198

Re: BBC Master screen interference PiTube direct

I'm wondering about contention - with the internal adapter, the Pi is on the main 6502 bus. If it's driving the bus at a bad time, would the video ULA pick up the Pi data mixed with the RAM's video data?
by BigEd
Wed Dec 13, 2017 12:55 pm
Forum: hardware
Topic: BBC Master screen interference PiTube direct
Replies: 55
Views: 1198

Re: BBC Master screen interference PiTube direct

I don't think this is data corruption, if the screen is OK when BREAK is held down. I think I'm with Dominic, that it could be power supply related. Is it possible with Kjell's internal adapter to cut the power from Master to Pi and to power the Pi separately? Or, is it possible for someone with thi...

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