Search found 190 matches

by cmorley
Sat Sep 23, 2017 7:57 pm
Forum: for sale / freebies
Topic: New Model B upgrades EEPROM, SRAM, adapters etc (BooBip)
Replies: 4
Views: 113

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

1) the probes attached to ICs under the keyboard and enthusiastic use of the keyboard caused crashes 2) when I died in Ghouls it always crashed when starting with the next life. Various other programs were also a bit flaky but not so consistently Any ideas if these boards have the same / similar is...
by cmorley
Sat Sep 23, 2017 6:42 pm
Forum: for sale / freebies
Topic: Test equipment for sale + CROs
Replies: 23
Views: 652

Re: Test equipment for sale

I'm declaring an interest in one "100MHz 2 channel, Rapid Electronics branded analogue CRO". If it's okay, I'll collect at the Abug meet-up. PC 'scopes and LCD storage 'scopes are fine as practical test tools, but just don't bring back the memories of my collage years working with a real ...
by cmorley
Sat Sep 23, 2017 3:17 pm
Forum: for sale / freebies
Topic: New Model B upgrades EEPROM, SRAM, adapters etc (BooBip)
Replies: 4
Views: 113

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

Hi All, All my (BooBip.com) Acorn memory adapters/upgrades are still current and still available to purchase. They are cheaper direct than via that well known auction site. I'm holding stock of every upgrade at the moment but if I do run out then I can make more within a few days normally... so if t...
by cmorley
Sat Sep 23, 2017 2:38 pm
Forum: for sale / freebies
Topic: Test equipment for sale + CROs
Replies: 23
Views: 652

Re: Test equipment for sale

I have got the CROs back at my house now. All ex-academic environment so some have departmental markings from their past lives. All from a lab so all have some scratches or small dents etc from careless students! All need good homes for retirement :) I need to test them and give them a clean. I'll g...
by cmorley
Tue Sep 19, 2017 8:09 pm
Forum: general
Topic: Today I received.....
Replies: 4144
Views: 215899

Re: Today I received.....

The newish cheaper flukes which were originally destined for the Asian market are pretty good value. I bought a Fluke 17B+ for around £90 IIRC and I've been very pleased with it.
by cmorley
Tue Sep 12, 2017 6:22 pm
Forum: hardware
Topic: New and interesting BBC fault
Replies: 14
Views: 367

Re: New and interesting BBC fault

Boydie wrote:Still not too sure how inserting a ROM could cause IC20 to fail so spectacularly...<snip>...the machine has always been slightly iffy whether it recognised ROMs


Maybe just the straw that broke the camel's back?
by cmorley
Tue Sep 12, 2017 6:19 pm
Forum: hardware
Topic: Desoldering components
Replies: 10
Views: 248

Re: Desoldering components

The vacuum solder stations work well like the Duratool D00672. If you use braid then you need quality stuff with decent flux in or to flux the cheap stuff before you use it. Then it works fine. As Rob said adding fresh solder helps a lot as this helps conduct the heat to get a proper melt when you g...
by cmorley
Mon Sep 11, 2017 8:40 pm
Forum: hardware
Topic: Troubleshooting my latest BBC B
Replies: 70
Views: 896

Re: Troubleshooting my latest BBC B

Sounds similar to the !RSTA problem I had on an issue 7. Dry joint presumably from the factory.

http://stardot.org.uk/forums/viewtopic.php?f=3&t=13313#p173697

The sys via reset pin would charge up after a few seconds & it would work after a BREAK press.
by cmorley
Sat Sep 09, 2017 10:20 am
Forum: hardware
Topic: New 65C02/W65C816 copro
Replies: 65
Views: 2215

Re: New 65C02/W65C816 copro

I need to take more measurements before I am sure but I think the WDC 65C02 violates the minimum address hold "guaranteed" in the datasheet on some writes. The address then changes before the write cycle is concluded. The RAM is 10ns ISSI stuff so performs a write to that memory too becaus...
by cmorley
Fri Sep 08, 2017 12:34 pm
Forum: hardware
Topic: New 65C02/W65C816 copro
Replies: 65
Views: 2215

Re: New 65C02/W65C816 copro

For those interested in hardware/tech details: A very frustrating intermittent "hang" (spoiler alert) now squashed! I use the serial port to remote my dev beeb and it was hanging with the 2nd processor when issuing *fx commands - I mute the screen output when sending program listings to sp...
by cmorley
Thu Sep 07, 2017 5:57 pm
Forum: for sale / freebies
Topic: Test equipment for sale + CROs
Replies: 23
Views: 652

Re: Test equipment for sale

No problem. I'll make a list of people interested in CROs & get back to you in a few weeks.
by cmorley
Thu Sep 07, 2017 9:18 am
Forum: for sale / freebies
Topic: Test equipment for sale + CROs
Replies: 23
Views: 652

Re: Test equipment for sale

All but a few picoscopes gone now.

The nice boxed mixed signal picoscope is still there with probes. I'll take £210 for that.
The unboxed MSO picoscope too, no analogue probes but does have the digital breakout lead. I'll take £175 for it.
The 100MHz picoscope is left (no probes). £175 anyone?
by cmorley
Wed Sep 06, 2017 1:24 pm
Forum: hardware
Topic: New 65C02/W65C816 copro
Replies: 65
Views: 2215

Re: New 65C02/W65C816 copro

What I would like is a socketed ROM so I could write my own boot code and have non-host ROMS (I did this on my 65816 so I could free up a ROM slot on the beeb). My main request would be to have a header (not necessarily fitted) that brought out all the main signals A[23..0], D[7..0], RnW..etc plus ...
by cmorley
Wed Sep 06, 2017 10:20 am
Forum: hardware
Topic: New 65C02/W65C816 copro
Replies: 65
Views: 2215

Re: New 65C02/W65C816 copro

Chinese alternative ? The problem with chips from eBay or aliexpress is you can end up with almost anything badged up as the part you wanted. Often old recycled parts labelled as newer faster parts. This happens a lot with eproms for example. I've had ancient TI EPROMs rebadged as 'genuine' ST part...
by cmorley
Wed Sep 06, 2017 8:06 am
Forum: hardware
Topic: New 65C02/W65C816 copro
Replies: 65
Views: 2215

Re: New 65C02/W65C816 copro

I do remember that I bought them from a USA based supplier that has a UK area of their website so that you can buy in GBP. Mouser sell them. They are £6.29@1 or £5.29@10 + VAT. So £6.50 for the chip in tens plus an extra £1 or so for some 3.3v-5v buffers. That's pretty much a third of the bill of m...
by cmorley
Tue Sep 05, 2017 4:30 pm
Forum: hardware
Topic: Quicky question: BBC Micro ROM <--> keyboard clearance
Replies: 8
Views: 278

Re: Quicky question: BBC Micro ROM <--> keyboard clearance

Yes that's the board.

I just measured one with an eprom in and it is 20.5mm tall from pin tip to EPROM top. How far it sits into the sockets on the BBC is going to depend on the BBC sockets...
by cmorley
Tue Sep 05, 2017 3:26 pm
Forum: hardware
Topic: Quicky question: BBC Micro ROM <--> keyboard clearance
Replies: 8
Views: 278

Re: Quicky question: BBC Micro ROM <--> keyboard clearance

Not a lot! You can just fit an EPROM in a socket on a plug in board (standard 1.6mm PCB)... but only just. The first thing to hit is the pins from the components on the solder side of the keyboard - these press and scratch the device below. My SRAM/OSRAM boards fit with a small amount of clearance w...
by cmorley
Tue Sep 05, 2017 3:18 pm
Forum: hardware
Topic: New 65C02/W65C816 copro
Replies: 65
Views: 2215

Re: New 65C02/W65C816 copro

Ok, I'm not sure where I should go with this project anymore. Straw poll time. I need some management features so was going to add those to the boot ROM or shoehorn them in somehow. Basic stuff like change the PLL divisors so I can change the clock speed on the fly. I am also tempted to add some ext...
by cmorley
Fri Sep 01, 2017 4:47 pm
Forum: hardware
Topic: New 65C02/W65C816 copro
Replies: 65
Views: 2215

Re: New 65C02/W65C816 copro

Up and running. Photo1058.jpg The version I got from Ian Bell's website seems to be hacked with commander firebud instead of Jameson. You start with billions of credits and all the gear. Maybe I can find a different version. Is there any way to skip the intro? I tried the normal BBC version and neve...
by cmorley
Fri Sep 01, 2017 10:27 am
Forum: hardware
Topic: New 65C02/W65C816 copro
Replies: 65
Views: 2215

Re: New 65C02/W65C816 copro

Actually, it looks like I did a one byte patch to the Tube Client ROM to end the copy at &FEDF instead of &FEEF: https://github.com/hoglet67/PiTubeDirect/commit/72229ce069142361ea2be67752b233269ccf0a14#diff-efa18eea05f756d5df13bacaf0c1a728 Ah, in the pi you did. I was looking at the ROM I e...
by cmorley
Fri Sep 01, 2017 7:22 am
Forum: hardware
Topic: New 65C02/W65C816 copro
Replies: 65
Views: 2215

Re: New 65C02/W65C816 copro

I assume your bank select gets triggered on the read during the ROM initialisation copy so the ROM copies the register value and writes the register - instead of copying the ROM value and writing to RAM on an original 2nd processor. Still a long way to go but... Photo1055.jpg Not sure yet how fast t...
by cmorley
Wed Aug 30, 2017 9:45 pm
Forum: hardware
Topic: New 65C02/W65C816 copro
Replies: 65
Views: 2215

Re: New 65C02/W65C816 copro

Yes normal BASIC 2 seems to transfer over OK now and runs it seems. I will look into the IO address space decoding. I probably get aliased copies of the tube registers so the ROM->RAM copy was probably sending FFs to the host by mistake in all 4 fifos.... I bet that's what it is. Thanks for the benc...
by cmorley
Wed Aug 30, 2017 9:15 pm
Forum: hardware
Topic: New 65C02/W65C816 copro
Replies: 65
Views: 2215

Re: New 65C02/W65C816 copro

The 6502 Co Pro in the Matchbox Co Pro and in PiTubeDirect both implement banked memory using the following model: The page size is 8KB, and so there are 8 bank selection registers: - 0xFEE0 controls the memory mapped in to 0x0000-0x1FFF - 0xFEE1 controls the memory mapped in to 0x2000-0x3FFF - ......
by cmorley
Wed Aug 30, 2017 8:59 pm
Forum: hardware
Topic: New 65C02/W65C816 copro
Replies: 65
Views: 2215

Re: New 65C02/W65C816 copro

Humm... so I changed my IO address mask to copy the hardware and it works. I looked in the ROM and it appears that FEE0-FEF8 are unused (just &FF) but annexing this for IO seemed to have it over... presumably some comms subroutines use this memory. I'll search now I know what memory caused the p...
by cmorley
Wed Aug 30, 2017 3:40 pm
Forum: hardware
Topic: New 65C02/W65C816 copro
Replies: 65
Views: 2215

Re: New 65C02/W65C816 copro

Despite the bird's nest of wires I've got raw flawless comms between host & parasite now. The signal integrity from my patch wires (coloured ribbon cable) is pretty poor with a lot of crosstalk but hey, if it works like that it should work with a propper cable. I need to add some snubber resisto...
by cmorley
Mon Aug 28, 2017 11:15 am
Forum: hardware
Topic: New 65C02/W65C816 copro
Replies: 65
Views: 2215

Re: New 65C02/W65C816 copro

1024MAK wrote:What, no blinking LEDs :shock:


Near the yellow link wire is a yellow 3mm LED :D
by cmorley
Sun Aug 27, 2017 1:11 pm
Forum: hardware
Topic: New 65C02/W65C816 copro
Replies: 65
Views: 2215

Re: New 65C02/W65C816 copro

So far so good...

For all you who like WIP project pics:

Photo1053.jpg


Photo1052.jpg


The RAM is on the underside.

I've already got the 2nd CPU running. Next step is the Tube ULA HDL.
by cmorley
Thu Aug 24, 2017 6:10 am
Forum: for sale / freebies
Topic: Test equipment for sale + CROs
Replies: 23
Views: 652

Re: Test equipment for sale

Good to hear they've arrived. For accuracy and high frequncies don't forget to use the ground strap which plugs in at the probe end - otherwise it will measure a distorted signal just like a scope would with a big measurement loop. When I tested them they seemed to pick up the frequncy fine but were...
by cmorley
Wed Aug 23, 2017 10:03 am
Forum: software: other
Topic: not in the books : lda#&80:sta &fe30
Replies: 6
Views: 397

Re: not in the books : lda#&80:sta &fe30

Shadow RAM is the top bit IIRC. What is the disassembly from? Perhaps B+ or some of the expansion board manufacturers (Watford/Solidisk) made FE30 readable for the shadow bit? Edit(s): No, it is the MOS graphics memory select on the Master (4K RAM &8000-&8FFF) or extra 12K on B+. (Shadow is ...
by cmorley
Tue Aug 22, 2017 5:15 pm
Forum: general
Topic: Today I built ...
Replies: 19
Views: 816

Re: Today I built ...

Today I built...

Photo1051.jpg


Now it is time to put the soldering iron down and step back from the antistatic mat! I think I'll clean and test them tomorrow!

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