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by BigEd
Fri Dec 15, 2017 9:45 pm
Forum: archive requests
Topic: BOS ROM for PMS B2P
Replies: 13
Views: 511

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: 51
Views: 797

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: 51
Views: 797

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: 6
Views: 98

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: 511

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: 438

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: 51
Views: 797

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: 706
Views: 34119

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: 51
Views: 797

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: 51
Views: 797

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: 51
Views: 797

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: 51
Views: 797

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...
by BigEd
Wed Dec 13, 2017 9:37 am
Forum: hardware
Topic: Acorn's Second Processors and the Tube - what, and why
Replies: 11
Views: 438

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

I've added a few more points to the bottom of the head post.
by BigEd
Tue Dec 12, 2017 7:45 pm
Forum: hardware
Topic: Beeb FPGA port to Spectrum Next
Replies: 38
Views: 849

Re: Beeb FPGA port to Spectrum Next

OK, new thread here about the Tube and Second Processors. Please comment there on that.
by BigEd
Tue Dec 12, 2017 7:43 pm
Forum: hardware
Topic: Acorn's Second Processors and the Tube - what, and why
Replies: 11
Views: 438

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

I thought I'd try my hand at explaining what the Second Processors are all about. I may well be duplicating some existing explanation - I'll be happy to accept corrections, clarifications and links. See for example the first few paragraphs of Acorn's Tube Application Note , the various resources on ...
by BigEd
Tue Dec 12, 2017 9:41 am
Forum: hardware
Topic: Beeb FPGA port to Spectrum Next
Replies: 38
Views: 849

Re: Beeb FPGA port to Spectrum Next

These questions and others could perhaps best be handled in a 'getting started with second processors' thread - which may or may not yet exist. Or a page on the BeebWiki. I'm just going out for the day, but might make a start this evening, if no-one beats me to it.
by BigEd
Tue Dec 12, 2017 7:37 am
Forum: hardware
Topic: Beeb FPGA port to Spectrum Next
Replies: 38
Views: 849

Re: Beeb FPGA port to Spectrum Next

As the FPGA in the Next is one size bigger than the one in the Matchbox , all the Matchbox cores should fit. So, in due course, there's a good chance any of them could be got to run. However, actually making any core work is going to take some fiddling, with a real card. It seems even the Next team ...
by BigEd
Sun Dec 10, 2017 6:59 pm
Forum: acorn atom
Topic: ICE T65/Z80/6809
Replies: 615
Views: 30871

Re: ICE T65/Z80/6809

I haven't been able to get a forecast about the product line, only a response about the specific variant: Please understand that we can't give a suggestion about an availability in the future. All we can say at the moment is, we will take the GODIL40_XC3S250E back into our shop if we will receive i...
by BigEd
Sun Dec 10, 2017 4:57 pm
Forum: hardware
Topic: how to do ? raspberry pi 2 and beeb b lost it
Replies: 43
Views: 564

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

unzip gives you about 4MB, not 4GB!!
by BigEd
Sun Dec 10, 2017 3:51 pm
Forum: hardware
Topic: how to do ? raspberry pi 2 and beeb b lost it
Replies: 43
Views: 564

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

And turn on the power! (Ideally power the Pi from the Beeb's 5V line over the Tube cable.)
by BigEd
Fri Dec 08, 2017 10:26 pm
Forum: other vintage computer hardware, software and games
Topic: Computer ad and review compilations
Replies: 5
Views: 186

Re: Computer ad and review compilations

There's a great collection of adverts, many with their background stories, organised by time and by manufacturer, at nosher:
A History of the Early Computer Industry in 300 Adverts
Image
by BigEd
Fri Dec 08, 2017 10:19 pm
Forum: hardware
Topic: Beeb FPGA port to Spectrum Next
Replies: 38
Views: 849

Re: Beeb FPGA port to Spectrum Next

(Thanks for the photos northernbob! I'm tempted to say that I see relatively few capacitors by the FPGA and the SRAMs - let's see what more experienced eyes see.)
by BigEd
Fri Dec 08, 2017 7:42 pm
Forum: hardware
Topic: Beeb FPGA port to Spectrum Next
Replies: 38
Views: 849

Re: Beeb FPGA port to Spectrum Next

I'd certainly be happy to see a fully open source release - especially as I'm a backer, and it was described as such.
by BigEd
Fri Dec 08, 2017 7:33 pm
Forum: hardware
Topic: Beeb FPGA port to Spectrum Next
Replies: 38
Views: 849

Re: Beeb FPGA port to Spectrum Next

I see a number of resistors and resistor networks near the edge connector - I'm interested to find out how 5V-compatible it is. It seems there are those who have doubts as to how safe the resistor network approach is, while the Spectrum Next people believe they've done adequate testing: https://www...
by BigEd
Fri Dec 08, 2017 7:28 pm
Forum: hardware
Topic: Beeb FPGA port to Spectrum Next
Replies: 38
Views: 849

Re: Beeb FPGA port to Spectrum Next

by BigEd
Fri Dec 08, 2017 6:12 pm
Forum: off-topic
Topic: online study?
Replies: 18
Views: 452

Re: online study?

I wonder if you can confirm a theory of mine, TopBanana - that hiring people is about taking the lowest-risk option. You don't want the best-qualified or the fastest worker or the most personable, rather you want the person who will need least managing and get the job done. If that's right, it's som...
by BigEd
Fri Dec 08, 2017 6:09 pm
Forum: hardware
Topic: BBC Master screen interference PiTube direct
Replies: 51
Views: 797

Re: BBC Master screen interference PiTube direct

hoglet wrote:...
What version of PiTubeDirect are you running?

The best way to tell this is to switch to the 65C02 Co Pro (Co Pro 0), and then enter:

Code: Select all

OLD
LIST

and post a photo of what you get.

Can I recommend

Code: Select all

OLD
LIST ,9

(LIST comma 9) instead?
by BigEd
Fri Dec 08, 2017 6:07 pm
Forum: hardware
Topic: Beeb FPGA port to Spectrum Next
Replies: 38
Views: 849

Re: Beeb FPGA port to Spectrum Next

I reckon it's the 96k-sized *.FW file - the firmware - which does the job of reading the *.TBU bitstream file and updating the EEPROM. But is this a Z80 application, or something else?
by BigEd
Fri Dec 08, 2017 4:43 pm
Forum: hardware
Topic: Beeb FPGA port to Spectrum Next
Replies: 38
Views: 849

Re: Beeb FPGA port to Spectrum Next

It includes the following features: - Master 128 mode and Model B mode (including ROM images for both) - the ICE T65 debugger (with AVR supervisor core), wired to the Tx and Rx pins on the esp8266 connector - the 65C02 Co Processor - Beeb SID - Music 5000 This uses about 60% of the LUTs, so things ...

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