Anyone got Communicator system software? (Basic has 65816 assembler)

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BigEd
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Anyone got Communicator system software? (Basic has 65816 assembler)

Postby BigEd » Mon Jul 04, 2016 11:51 am

Has anyone got any ROMs or disks or anything relating to Acorn's short-lived non-consumer product the Communicator? It had a 16-bit CPU in it, the 65816 which supports 6502 code, and a half-meg of RAM and some kind of task-switching OS.

Particularly of interest, the Basic's assembler had support for the 65816's extra opcodes and extra registers:
The Communicator has its own version of
Basic, curiously named Version 4.0 (curious
because the Master also purports to run
Version 4). It contains most of the extensions
that the Master's Basic has, but its assembler
and machine-code interfaces are quite
different. Unsurprisingly, the assembler
supports the full 65816 instruction set, and has
a number of new pseudo-variables to represent
registers and operating system vectors and
calls.


There's some info about the machine at http://chrisacorns.computinghistory.org ... cator.html
Looks like a 1988 product.

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Re: Anyone got Communicator system software? (Basic has 65816 assembler)

Postby z0m8ied0g » Fri Jul 08, 2016 12:00 am

I've got a communicator and its got its own strange multitasking OS.
You can pause applications and switch between them. It has View and ViewSheet in rom along with a terminal, calculator and basic.
It also has a phonebook that can dial numbers.

There is no disk interface as far as I know, it is designed to use on Prestel or other dial in services or via Econet.
You can save files to a ram filesystem (64k) or a CMOS (permament 32k) file system. Its mainly intended to use via Econet but I presume that the RAM and CMOS are there so you don't have to always be connected.

I will have a go at dumping the roms and copying them to my MDFS when I get the chance.
Acorn... lots of Acorn... http://blog.retroacorn.net

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Re: Anyone got Communicator system software? (Basic has 65816 assembler)

Postby BigEd » Fri Jul 08, 2016 9:13 am

Ah - everything is on the ROMs. It would be great if you could dump them and publish!

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Re: Anyone got Communicator system software? (Basic has 65816 assembler)

Postby BigEd » Sun Jul 10, 2016 12:48 pm

By coincidence, I had hands on a briefcase model Communicator at The National Museum of Computing yesterday - here are a couple of photos. Looks like the assembler does indeed understand at least some 65816 opcodes, and the Basic has rather more than 64k of workspace available. (Edit: oops, no, has just under 64k of workspace.)
Acorn Communicator Briefcase.JPG
Briefcase Communicator

Communicator Basic.JPG
Basic on the Communicator

Communicator Crash.JPG
Crash!
Last edited by BigEd on Tue May 30, 2017 9:54 am, edited 1 time in total.

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Re: Anyone got Communicator system software? (Basic has 65816 assembler)

Postby Pernod » Tue Jul 19, 2016 11:32 am

z0m8ied0g wrote:I will have a go at dumping the roms and copying them to my MDFS when I get the chance.

Looking forward to seeing these, hope you manage to dump them soon. They'll be preserved in MAME shortly after.
- Nigel

BBC Model B, ATPL Sidewise, Acorn Speech, 2xWatford Floppy Drives, AMX Mouse, Viglen case, etc.

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Re: Anyone got Communicator system software? (Basic has 65816 assembler)

Postby atcurtis » Tue May 16, 2017 6:37 am

Were the ROMs ever dumped? I'm curious if BASIC on it supported the paging/large memory space or was it just running in 6502 mode.

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Re: Anyone got Communicator system software? (Basic has 65816 assembler)

Postby jgharston » Tue May 16, 2017 1:07 pm

atcurtis wrote:Were the ROMs ever dumped? I'm curious if BASIC on it supported the paging/large memory space or was it just running in 6502 mode.

Here: http://mdfs.net/System/ROMs/AcornMOS/Communi100/
I haven't got around to disassembling them yet. I got a phone call this morning from my agency asking if I was available for a public sector Windows 7 rollout starting tomorrow.....

Code: Select all

$ bbcbasic
PDP11 BBC BASIC IV Version 0.25
(C) Copyright J.G.Harston 1989,2005-2015
>_

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Re: Anyone got Communicator system software? (Basic has 65816 assembler)

Postby davidb » Tue May 16, 2017 1:23 pm

jgharston wrote:I haven't got around to disassembling them yet. I got a phone call this morning from my agency asking if I was available for a public sector Windows 7 rollout starting tomorrow.....

The government just can't get its priorities right, can it? ;)

Back on topic (sort of): the page on Chris's Acorns speculates that the ULA in the Communicator could be the same as the one from the Electron but, looking at z0m8ied0g's Acorn Communicator - Dialling ViewData BBS video, it looks like it's using MODE 7 to display Viewdata. So, was the ULA in the Communicator an evolution of the Electron ULA or the video ULA from the BBC Micro?

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Re: Anyone got Communicator system software? (Basic has 65816 assembler)

Postby 1024MAK » Tue May 16, 2017 3:06 pm

davidb wrote:Back on topic (sort of): the page on Chris's Acorns speculates that the ULA in the Communicator could be the same as the one from the Electron but, looking at z0m8ied0g's Acorn Communicator - Dialling ViewData BBS video, it looks like it's using MODE 7 to display Viewdata. So, was the ULA in the Communicator an evolution of the Electron ULA or the video ULA from the BBC Micro?

In the picture of the board on Chris's Acorns, there is a Philips SAA5240 40 pin DIL chip. This is one of the Teletext range of chips. I don't know the full details, but it does contain a Teletext display system. It is controlled via a I2C bus.

See http://mdfs.net/Archive/BBCMicro/2010/02/10/021159.htm and http://www.heyrick.co.uk/software/winttx/datasheets.html

Mark
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BigEd
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Re: Anyone got Communicator system software? (Basic has 65816 assembler)

Postby BigEd » Tue May 16, 2017 3:34 pm

jgharston wrote:
atcurtis wrote:Were the ROMs ever dumped? I'm curious if BASIC on it supported the paging/large memory space or was it just running in 6502 mode.

Here: http://mdfs.net/System/ROMs/AcornMOS/Communi100/
I haven't got around to disassembling them yet. I got a phone call this morning from my agency asking if I was available for a public sector Windows 7 rollout starting tomorrow.....

Thanks JGH! Looks like a Basic in ROM 3:

Code: Select all

0004b00: 8218 00ef 5200 0001 0201 0000 0000 4241  ....R.........BA
0004b10: 5349 4300 5b73 697a 655d 0082 4800 6026  SIC.[size]..H.`&
0004b20: 0442 4153 4943 0028 4329 3139 3836 2041  .BASIC.(C)1986 A
0004b30: 636f 726e 0a0d 0000 4b81 c910 0000 6f15  corn....K.....o.

And Rom 0 looks like an OS, in the sense that if you take the top of the ROM to contain the reset vector, the code at that vector makes a little bit of sense.

Code: Select all

000fff0: 8f00 0044 5c9a b0ff 0000 0000 4fb0 1f46  ...D\.......O..F

Code: Select all

; reset ?
     78         sei
B050 18         clc
B051 FB         xce (65816 mode set)
B052 AF0000     lda 400000
B056 78     x   sei ???
B057 18         clc
B058 FB         xce ???
B059 C238       rep 38
B05B E220       sep 20


(I don't have a trusty 65816 disassembler)

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Re: Anyone got Communicator system software? (Basic has 65816 assembler)

Postby atcurtis » Wed May 17, 2017 11:14 am

Hmm... The fun thing will be how to work out the memory map since the whole of the first ROM can't be the whole of the first 64K because the stack has to live somewhere there.

It looks like it uses the lots-of-modules approach like RiscOS and the COP entry looks like the inspiration for ARM's SWIs since we don't have the 6502 style OSWRCH/etc calls. Amusingly enough, it looks like some of the module apps are written in BASIC.

By quick visual inspection:

ROM-0 0x0000 ViewSheet
ROM-0 0x5500 VDU
ROM-0 0x7e00 Keyboard
ROM-0 0x8600 Timer2
ROM-0 0x8900 Net/ACCESS/BYE/CDIR/DIR/FLIP/INFO/LIB/LOGON/PASS/I/OPT
ROM-0 0xae00 MOS/HELP/LOAD/SAVE/KEY/FX/EXEC/RESET/LCB/CLOSEALL/DELETE/RENAME/CAT/EX
ROM-1 0x0000 IIC
ROM-1 0x0200 Clock/LTime/Set/Help
ROM-1 0x0500 Help
ROM-1 0x1100 ViewData
ROM-1 0x3000 Modem
ROM-1 0x5600 E.TTY
ROM-1 0x5a00 E.BBC
ROM-1 0x5e00 E.VIDEOTEX
ROM-1 0x6400 E.VT100
ROM-1 0x7400 SCRDMP
ROM-1 0x7900 Centronics
ROM-1 0x8000 Printer
ROM-1 0x9900 KEYPAGE
ROM-1 0xc200 Econet
ROM-1 0xa300 NetPrint
ROM-1 0xaf00 Arithmetic
ROM-1 0xd000 Name/PName
ROM-1 0xda00 Calculator (BASIC)
ROM-2 0x0000 Brother
ROM-2 0x0200 TXTDMP
ROM-2 0x0500 Phone (BASIC)
ROM-3 0x0000 VIEW
ROM-3 0x4b00 BASIC
ROM-3 0x9e00 Configure (BASIC)
ROM-3 0xc200 Carousel (BASIC)

Fascinating.

Module header:
0x0000 BRL <relative entry point>
0x0003 dw <length of module?>
0x0005 dw 0x0000
0x0007 db 0x01
0x0008 db flags // 0x80 seems to indicate BASIC app
0x0009 db ??
0x000a dw 0x0000
0x000c dw ????
0x000e ASCIIZ module name

Will need to hack an existing 65816 disassembler since almost all the ones I can find seem geared to handle SNES ROMs...

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Re: Anyone got Communicator system software? (Basic has 65816 assembler)

Postby cmjones01 » Thu May 18, 2017 12:50 pm

1024MAK wrote:
davidb wrote:Back on topic (sort of): the page on Chris's Acorns speculates that the ULA in the Communicator could be the same as the one from the Electron but, looking at z0m8ied0g's Acorn Communicator - Dialling ViewData BBS video, it looks like it's using MODE 7 to display Viewdata. So, was the ULA in the Communicator an evolution of the Electron ULA or the video ULA from the BBC Micro?

In the picture of the board on Chris's Acorns, there is a Philips SAA5240 40 pin DIL chip. This is one of the Teletext range of chips. I don't know the full details, but it does contain a Teletext display system. It is controlled via a I2C bus.

Looking at that video, the character set on the Viewdata display has the distinctive look of the SAA5240 series display system. Where the SAA5050 in the Beeb uses a 6x8 character matrix with algorithmically-generated corner rounding, the SAA5240 series uses a full 12x10 character matrix in its ROM to give more detailed, especially curved, characters. I reckon, therefore, that the Communicator is using its SAA5240 for Viewdata video output. I wonder if it's driven entirely by the I2C bus or whether there's some clever multiplexing thing going on with the SAA5240's video RAM?

Chris

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Re: Anyone got Communicator system software? (Basic has 65816 assembler)

Postby jgharston » Thu May 18, 2017 1:06 pm

A brief initial look at the ROMs suggest they are laid out as:
ROM 0 top of memory map
ROM 1 next one down
ROM 2 next one down
ROM 3 next one down
so the ROM numbers go down in memory address, not upwards. Eg:
FFFFxx ROM 0
FFFExx ROM 1
FFFDxx ROM 2
FFFCxx ROM 3

A difficulty with writing a 65816 disassembler is that some instructions are different lengths depending on the contents of the FLAGS register when the code is actually being executing. You can't uniquely disassemble a chunk of code without that external context. I'll upload what I've got so far later.

Code: Select all

$ bbcbasic
PDP11 BBC BASIC IV Version 0.25
(C) Copyright J.G.Harston 1989,2005-2015
>_

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Re: Anyone got Communicator system software? (Basic has 65816 assembler)

Postby BigEd » Thu May 18, 2017 4:13 pm

It's true, but common practice seems to be to spend the majority of time in one chosen mode.

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Re: Anyone got Communicator system software? (Basic has 65816 assembler)

Postby Pernod » Thu May 25, 2017 12:23 pm

We now have a preliminary driver in MAME for the Communicator. It doesn't do much though due to lack of technical information. The machine starts but screen output is garbled.

Anyone have or know whether CCH has the Technical Reference Manuals?
- Nigel

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Re: Anyone got Communicator system software? (Basic has 65816 assembler)

Postby Pernod » Thu May 25, 2017 1:20 pm

We have now improved screen output:
0001.jpg

No keyboard input yet so can't do anything with it.
Last edited by Pernod on Fri May 26, 2017 9:00 pm, edited 1 time in total.
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Re: Anyone got Communicator system software? (Basic has 65816 assembler)

Postby jgharston » Thu May 25, 2017 4:19 pm

I've got the skeleton code for a 65816 disassembler, but have been rather busy the last few days. Tomorrow is the deadline for getting general election leaflets to the Royal Mail - or they potentially get delivered after the election! :D Just finished sorting ours out an hour ago, so I can get back to some proper work. ;)

A couple of hours should get me most of the disassembler working as most of it is extending the data width of the 65x2 disassembler and adding the extra opcodes. And I've got a long Bank Holiday weekend with my hardware before I have to go trolling off with just my laptop. Working in Bootle next week.

Code: Select all

$ bbcbasic
PDP11 BBC BASIC IV Version 0.25
(C) Copyright J.G.Harston 1989,2005-2015
>_

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Re: Anyone got Communicator system software? (Basic has 65816 assembler)

Postby Pernod » Thu May 25, 2017 4:31 pm

jgharston wrote:I've got the skeleton code for a 65816 disassembler.

Why not use the MAME debugger. I can post a tiny MAME build that only includes this machine if you'd find it useful?
- Nigel

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Re: Anyone got Communicator system software? (Basic has 65816 assembler)

Postby jgharston » Sat May 27, 2017 12:40 am

Only needed a dozen or so lines added to the 6502 disassembly module make a 65816 module. Initial disassembly of ROM 0 and intial stab at memory layout here.

Code: Select all

$ bbcbasic
PDP11 BBC BASIC IV Version 0.25
(C) Copyright J.G.Harston 1989,2005-2015
>_

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Re: Anyone got Communicator system software? (Basic has 65816 assembler)

Postby BigEd » Sat May 27, 2017 6:53 am

Thanks JGH, I'd like to have a look - but the zip file is a broken link for me.

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Re: Anyone got Communicator system software? (Basic has 65816 assembler)

Postby Pernod » Sat May 27, 2017 10:11 am

BigEd wrote:Thanks JGH, I'd like to have a look - but the zip file is a broken link for me.

There's a typo in the link, try http://mdfs.net/System/ROMs/AcornMOS/Co ... v100-0.zip

We've now implemented the Electron ULA into the Communicator in MAME and have colour and keyboard support. The keyboard matrix is unknown so still not usable.
- Nigel

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Re: Anyone got Communicator system software? (Basic has 65816 assembler)

Postby BigEd » Sat May 27, 2017 11:08 am

Thanks!

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Re: Anyone got Communicator system software? (Basic has 65816 assembler)

Postby jgharston » Mon May 29, 2017 1:58 pm

I've written some code to split the ROM images into individual modules and done an initial disassembly of BASIC:
http://mdfs.net/System/ROMs/AcornMOS/Communi100/

As well as using COP to make system calls there appears to be an entry block at &00FFxx, there are many calls to &00FF8C-&00FF98.

Some interesting things from looking at the BASIC programs.

Assembler-style labels can be set outside assembler code. It looks like it assigns the line number so you can RESTORE to them dynamically. Example:
20290 .h%(1)
20300 DATA1,"Number out of range.","",""
....
25870 RESTOREh%(d%):...


There appears to be a class of variables that start with '@', similar to Windows BASIC, for example @ECPHON%, @X%, @Y%, @OPT%.

Code: Select all

$ bbcbasic
PDP11 BBC BASIC IV Version 0.25
(C) Copyright J.G.Harston 1989,2005-2015
>_

paulb
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Re: Anyone got Communicator system software? (Basic has 65816 assembler)

Postby paulb » Mon May 29, 2017 2:23 pm

Is there a circuit diagram available for the Communicator anywhere? I guess if MAME supports it, there must be some idea of what the hardware is.

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Re: Anyone got Communicator system software? (Basic has 65816 assembler)

Postby Pernod » Mon May 29, 2017 2:45 pm

paulb wrote:Is there a circuit diagram available for the Communicator anywhere? I guess if MAME supports it, there must be some idea of what the hardware is.

No, we really need the technical manuals, especially to fill in the gaps we have with the keyboard matrix. I haven't worked on this in MAME, the ROMs were passed to someone that is much more familiar with 65816 machines. The machine is looking quite simple at the moment with the ULA being very similar to the Electron.
- Nigel

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Re: Anyone got Communicator system software? (Basic has 65816 assembler)

Postby jgharston » Mon May 29, 2017 4:41 pm

I've found the keyboard table in the Keyboard module:

Code: Select all

\ Keyboard table
\ ==============
\ 128 bytes from L82F6 to L8376
.L82F6
EQUS ":^[;l0okg6tf???",&CF
\     :^[;l0okg6tf      cF
EQUS "????d4esa2q?j8uh"
\         d4esa2q j8uh
EQUS "????",&8D,&89,&8F,&8C,&C8,&C2,&C5,&C7,&CD,&20,&CE,&0D
\            ->  f9  up  <-  c8  c2  c5  c7  cD spc  cE ret
EQUS &86,&88,&87,&83,"????????????"
\     f6  f8  f7  f3
EQUS "/p_-,i.9vrb5????"
\     /p_-,i.9vrb5
EQUS "????xwc3?",&09,"z1nym7"
\         xwc3?  tab  z1nym7
EQUS &C9,&C6,&CB,&C3,&7F,&8B,&8E,&80,&CA,&C4,&C0,&C1,"\]L",&1B
\     c9  c6  cB  c3 del cpy  dn  f0  cA  c4  c0  c1       esc
EQUS &84,&82,&85,&81,"????????????"
\     f4  f2  f5  f1

\ This gives this keyboard matrix
\     +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
\     | : | ^ | [ | ; | l | 0 | o | k | g | 6 | t | f |   |   |   |cF |
\     +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
\     |   |   |   |   | d | 4 | e | s | a | 2 | q |   | j | 8 | u | h |
\     +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
\     |   |   |   |   |-> |f9 |up |<- |c8 |c2 |c5 |c7 |cD |spc|cE |ret|
\     +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
\     |f6 |f8 |f7 |f3 |   |   |   |   |   |   |   |   |   |   |   |   |
\     +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
\     | / | p | _ | - | , | i | . | 9 | v | r | b | 5 |   |   |   |   |
\     +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
\     |   |   |   |   | x | w | c | 3 |   |tab| z | 1 | n | y | m | 7 |
\     +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
\     |c9 |c6 |cB |c3 |del|cpy|dn |f0 |cA |c4 |c0 |c1 | \ | ] | L |esc|
\     +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
\     |f4 |f2 |f5 |f1 |   |   |   |   |   |   |   |   |   |   |   |   |
\     +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+

It appears to be a fairly normal 8x16 matrix, but doesn't appear to have CAPS, and there isn't the non-IRQ-generating row that has the modifier keys on, SHIFT and CTRL, and on the BBC the startup links and on later machines ATL. Completely different from the rest of the Acorn series, so INKEY-num will map to different keys unless it is translated internally.

I've labelled the keycodes in the &Cx range as cX. These will be keys such as the keypad and FUNCTION, STOP, and stuff. The keycaps are shuch low contrast on the online photos of Communicators that I can't make out what they day. White lettering on grey background, I tell you.

Code: Select all

$ bbcbasic
PDP11 BBC BASIC IV Version 0.25
(C) Copyright J.G.Harston 1989,2005-2015
>_

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Re: Anyone got Communicator system software? (Basic has 65816 assembler)

Postby BigEd » Mon May 29, 2017 4:47 pm

Attachments
Screenshot 2017-05-29 at 17.48.02.png
Screenshot 2017-05-29 at 17.48.26.png
Last edited by BigEd on Mon May 29, 2017 4:49 pm, edited 1 time in total.

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Re: Anyone got Communicator system software? (Basic has 65816 assembler)

Postby Pernod » Mon May 29, 2017 4:48 pm

jgharston wrote:The keycaps are shuch low contrast on the online photos of Communicators that I can't make out what they day. White lettering on grey background, I tell you.

Thanks, that should fill in some of the unknowns, we're pretty much down to the non-alphanumerics. Beebmaster has a better photo at http://www.beebmaster.co.uk/Shows/Communicator3.html
- Nigel

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Re: Anyone got Communicator system software? (Basic has 65816 assembler)

Postby jgharston » Mon May 29, 2017 5:20 pm

Perfect, that lets me add it to: http://mdfs.net/Docs/Comp/Keyboard/

At a guess I'd say that HELP is f0 and STOP is f9. Could do with somebody with the hardware to do:
FOR A%=0 TO 7:OSCLI "FX"+STR$(221+A%)+","+STR$(128+16*(A%EOR4)):NEXT A%:*FX229,1
REPEAT:PRINT" ";RIGHT$("0"+STR$~GET,2);" ";:UNTIL FALSE

and dance across the keys and report what keycodes are reported.

Code: Select all

$ bbcbasic
PDP11 BBC BASIC IV Version 0.25
(C) Copyright J.G.Harston 1989,2005-2015
>_

paulb
Posts: 784
Joined: Mon Jan 20, 2014 9:02 pm

Re: Anyone got Communicator system software? (Basic has 65816 assembler)

Postby paulb » Mon May 29, 2017 5:41 pm

cmjones01 wrote:
1024MAK wrote:
davidb wrote:Back on topic (sort of): the page on Chris's Acorns speculates that the ULA in the Communicator could be the same as the one from the Electron but, looking at z0m8ied0g's Acorn Communicator - Dialling ViewData BBS video, it looks like it's using MODE 7 to display Viewdata. So, was the ULA in the Communicator an evolution of the Electron ULA or the video ULA from the BBC Micro?

In the picture of the board on Chris's Acorns, there is a Philips SAA5240 40 pin DIL chip. This is one of the Teletext range of chips. I don't know the full details, but it does contain a Teletext display system. It is controlled via a I2C bus.

Looking at that video, the character set on the Viewdata display has the distinctive look of the SAA5240 series display system. Where the SAA5050 in the Beeb uses a 6x8 character matrix with algorithmically-generated corner rounding, the SAA5240 series uses a full 12x10 character matrix in its ROM to give more detailed, especially curved, characters. I reckon, therefore, that the Communicator is using its SAA5240 for Viewdata video output. I wonder if it's driven entirely by the I2C bus or whether there's some clever multiplexing thing going on with the SAA5240's video RAM?


BeebMaster's picture from Wakefield 2017 shows a SAA5240P/A IC, so I guess we can be certain that this is how Viewdata was supported. Richard Murray has information about this in the context of the Ground Control teletext receiver.


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