BBC Master noob

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danielj
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Re: BBC Master noob

Post by danielj » Fri Feb 09, 2018 6:03 pm

Has anyone actually tried an NiMH cell in a master without the Diode :?

d.

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1024MAK
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Re: BBC Master noob

Post by 1024MAK » Fri Feb 09, 2018 6:21 pm

No. But if you added the appropriate circuitry, any rechargeable battery technology could be used.
However, it's not really worthwhile getting too carried away.

It is also possible to use 3V coin cells with a diode and an appropriate value resistor.

Mark
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Lardo Boffin
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Re: BBC Master noob

Post by Lardo Boffin » Fri Feb 09, 2018 6:50 pm

I haven’t sorted the battery CMOS yet (too busy packing) but would like if possible to test the 3.5” drive that came with it.
Whats the quickest way to do this (to minimise PSU up time and smells)? Try and format a disc and then write a simple file to it?

If so what are the ADFS commands to do this? I’ve only really used DFS before. Would I have to activate ADFS first, e.g. *ADFS or similar?

Many thanks!
BBC model B 32k issue 4, 16k sideways RAM, Watford 12 ROM board, Retroclinic Datacentre + HDD, Viglen twin 40/80 5.25" discs, acorn cassette, Acorn 6502 coproc
BBC model B 32k issue 7, turboMMC, Opus Challenger 3 512k, Pi 3 coproc
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danielj
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Re: BBC Master noob

Post by danielj » Fri Feb 09, 2018 6:51 pm

No ADFS format command built in to ADFS 3.2. Just use DFS - *FORM80 0 2

d.

(DFS/ADFS don't care about the size of your disks, so you can happily use 3.5" with DFS and 5.25" with ADFS)

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Lardo Boffin
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Re: BBC Master noob

Post by Lardo Boffin » Fri Feb 09, 2018 7:04 pm

danielj wrote:No ADFS format command built in to ADFS 3.2. Just use DFS - *FORM80 0 2

d.

(DFS/ADFS don't care about the size of your disks, so you can happily use 3.5" with DFS and 5.25" with ADFS)
Its built into DFS on the Master? Cool.
BBC model B 32k issue 4, 16k sideways RAM, Watford 12 ROM board, Retroclinic Datacentre + HDD, Viglen twin 40/80 5.25" discs, acorn cassette, Acorn 6502 coproc
BBC model B 32k issue 7, turboMMC, Opus Challenger 3 512k, Pi 3 coproc
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Lardo Boffin
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Re: BBC Master noob

Post by Lardo Boffin » Fri Feb 09, 2018 7:12 pm

So I struggled to create a file without a language present but it formatted and then *. worked so I suspect all is probably good!

Excellent.
BBC model B 32k issue 4, 16k sideways RAM, Watford 12 ROM board, Retroclinic Datacentre + HDD, Viglen twin 40/80 5.25" discs, acorn cassette, Acorn 6502 coproc
BBC model B 32k issue 7, turboMMC, Opus Challenger 3 512k, Pi 3 coproc
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danielj
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Re: BBC Master noob

Post by danielj » Fri Feb 09, 2018 7:20 pm

BASIC is there, it just doesn't know to use it as the default language as the cmos is fudged. *CO. LANG. <romno> is what you use to configure it. In the meantime, *BASIC will take you to a BASIC prompt. The default * prompt is the OS prompt - you can issue any * command you like from there.

d.

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1024MAK
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Re: BBC Master noob

Post by 1024MAK » Fri Feb 09, 2018 7:36 pm

Once the CMOS SRAM within the RTC chip has been "configured", the Master will be fully functional. The only thing the battery does, is supply power when mains power is not present (i.e. switched off) so that the SRAM can retain the settings.

The Master ROM chip contains the OS plus a number of applications, BASIC and a number of filing systems. A Master can be configured to use BASIC or one of the other applications (languages) once it has finished it's start up sequence. Or if no valid language is selected, it drops into a simple "monitor" mode where * commands can be entered.

Mark
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Re: BBC Master noob

Post by cmorley » Sat Feb 10, 2018 10:38 am

New to the Master as well I've been following this thread and others about CMOS batteries, *CONFIGURE etc.

I saw Daniel's comment about NiMH and did a bit of investigating.

It seems that Issue 2 motherbaords have Q4 a p channel jfet connected between the battery connector and ground. The gate is connected to 5VB so it goes high-z between drain and source when the machine is on thus preventing charging. There is a 470R resistor too presumably in case the jfet fails short or the gate comes adrift (Vgs=0 it will conduct). So no dice charging with this issue motherboard without modification.

The MDFS schematic shows issue 3 has grounded battery connector. So this can charge. (Hence the diodes and protection R in the battery pack wiring).

3 NiMH low self discharge cells in series with a current limiting resistor might be all that is needed. NiCad level trickle charge is bad @0.1C for NiMH but much lower trickle isn't (looking at the datasheets). Figures of C/30, C/40 to C/300 I've seen on various datasheets. Or fit a battery charge IC... or clamp to 1.3V per cell (3.9V) apparently increases the NiMH cell life.

Or use a BMS board and a single lipo cell.

I'll see what issue motherbaord I have and if it is a 3 then I might well fit NiMH... perhaps eneloop (Panasonic) or some other decent brand.

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Re: BBC Master noob

Post by crj » Sat Feb 10, 2018 3:30 pm

danielj wrote:BASIC is there, it just doesn't know to use it as the default language as the cmos is fudged. *CO. LANG. <romno> is what you use to configure it. In the meantime, *BASIC will take you to a BASIC prompt.
That assumes scrambling the CMOS hasn't accidentally unplugged BASIC.

*ROMS is a good first step, followed by *INSERT on anything which is unplugged but looks important.

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Re: BBC Master noob

Post by Lardo Boffin » Mon Feb 12, 2018 9:21 pm

I have a Master User Guide on its way which may answer this question but...

What can you plug into the audio out of a Master? I was thinking possibly an old set of PC speakers but then they would be stereo and I doubt the output is.

Also assuming you plug something into the audio out does it suppress sound from the speaker? The one thing I don’t like about the vanilla beeb is that it is not easy to change the volume and it surprisingly loud.

Thanks!
BBC model B 32k issue 4, 16k sideways RAM, Watford 12 ROM board, Retroclinic Datacentre + HDD, Viglen twin 40/80 5.25" discs, acorn cassette, Acorn 6502 coproc
BBC model B 32k issue 7, turboMMC, Opus Challenger 3 512k, Pi 3 coproc
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Re: BBC Master noob

Post by danielj » Mon Feb 12, 2018 9:24 pm

Funny you mention this. I just plugged it into the line-in on my PC and played it out of those speakers. Worked fine - it doesn't, however, suppress the internal speaker. :(

d.

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Lardo Boffin
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Re: BBC Master noob

Post by Lardo Boffin » Mon Feb 12, 2018 9:29 pm

danielj wrote:Funny you mention this. I just plugged it into the line-in on my PC and played it out of those speakers. Worked fine - it doesn't, however, suppress the internal speaker. :(

d.
Hmm. I guess its pretty easy to unplug the internal speaker on the Master so providing I always use speakers all should be good. :D

Time to eBay for some old speakers!
BBC model B 32k issue 4, 16k sideways RAM, Watford 12 ROM board, Retroclinic Datacentre + HDD, Viglen twin 40/80 5.25" discs, acorn cassette, Acorn 6502 coproc
BBC model B 32k issue 7, turboMMC, Opus Challenger 3 512k, Pi 3 coproc
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Re: BBC Master noob

Post by danielj » Mon Feb 12, 2018 9:31 pm

It's mono out (as it's only a single phono connector) - but just run it into a mono 3.5" jack and you'll be 'reet :)

d.

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Re: BBC Master noob

Post by CMcDougall » Mon Feb 12, 2018 10:29 pm

Lardo Boffin wrote:one thing I don’t like about the vanilla beeb is that it is not easy to change the volume and it surprisingly loud.!
easy as pie 8) :
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Re: BBC Master noob

Post by sydney » Mon Feb 12, 2018 10:48 pm

I connected the audio out to the audio pins on my scart connector so sound comes out of the tv. I think retroclinic sells scart cables with the audio connected if you don't fancy soldering it yourself.

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Re: BBC Master noob

Post by tricky » Tue Feb 13, 2018 8:14 am

That picture looks like a B.
It's quite easy to add a socket to the beeb so that the internal speaker is disconnected when you plug something in. I do all my Beebs and many my SCART leads with a plug for audio, very hand for when the volume at a show keeps changing.

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Re: BBC Master noob

Post by crj » Tue Feb 13, 2018 8:34 pm

danielj wrote:It's mono out (as it's only a single phono connector) - but just run it into a mono 3.5" jack and you'll be 'reet :)
Um. I assume you mean a 3.5mm jack. 3.5" would be... large. (-8

Note that if you plug a mono jack into a stereo input socket, you'll get sound only on the left channel, with the right channel silent. If you're at all handy at soldering, a better idea may be to make up your own load where the tip of the RCA plug goes to both tip and ring of a TRS 3.5mm jack.

(Alternatively, Maplin sells an adapter. I was about to be scathing about the likelihood that it would cost more than the BBC Master did, but astonishingly their price is actually fair for once!)

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Re: BBC Master noob

Post by Lardo Boffin » Tue Feb 13, 2018 8:52 pm

sydney wrote:I connected the audio out to the audio pins on my scart connector so sound comes out of the tv. I think retroclinic sells scart cables with the audio connected if you don't fancy soldering it yourself.
I have contacted Mark thanks and he can make me one up. My soldering skills are rudimentary. :D
BBC model B 32k issue 4, 16k sideways RAM, Watford 12 ROM board, Retroclinic Datacentre + HDD, Viglen twin 40/80 5.25" discs, acorn cassette, Acorn 6502 coproc
BBC model B 32k issue 7, turboMMC, Opus Challenger 3 512k, Pi 3 coproc
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