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Old 9th Apr 2019, 6:35 am   #1
Karen O
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Default My 'ASR 33' terminal

I just thought I'd reveal my latest computer-related creation. It's a terminal, complete with 25x16 character display and a card reader/punch

It runs at the lightning speed of 110 baud and is so dumb that it qualifies for the description 'decerebrate'.

I can once again experience that frustration at watching characters appear at the sedate pace of ten per second
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Old 9th Apr 2019, 6:48 am   #2
Radio Wrangler
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Default Re: My 'ASR 33' terminal

Future enhancements to include sound effects, the smell of the oil and and the smell of a hot motor?

David
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Old 9th Apr 2019, 6:59 am   #3
Karen O
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Default Re: My 'ASR 33' terminal

Hi David,

Well, maybe not the oil!

But I did seriously consider playing out samples when printing, returning the carriage, etc.

In the end I just added a little keyboard 'bleep' to acknowledge each key press.

Samples become tiring when they're identical every time, and I wouldn't go to the trouble of making dozens of them all with slight variations.
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Old 10th Apr 2019, 9:22 pm   #4
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Default Re: My 'ASR 33' terminal

How lovely!

Stylistically, it sort-of reminds me of the Texas Instruments "Silent-700" thermal-printing-terminal-with-acoustic-coupler-and-cassette-storage I used in the late-70s to prepare programs for submission via dialup to the University of Manchester's CDC7600 mainframe.
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Old 11th Apr 2019, 10:16 am   #5
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Default Re: My 'ASR 33' terminal

Lovely! I keep meaning to buy/make a paper tape reader!
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Old 11th Apr 2019, 3:54 pm   #6
Karen O
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Default Re: My 'ASR 33' terminal

Thank you G6Tanuki, Dominic!
I must admit I was going for the 'cuteness factor'.
I think its first application will be connection to a full emulation of NIBL on an SC/MP, using the original tty routines.
The only shortcoming may be the inability to stop the 'paper tape reader'. NIBL turned a flag on and off to control a 'reader relay' to throttle the reader.
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Old 11th Apr 2019, 6:17 pm   #7
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Default Re: My 'ASR 33' terminal

Smashing, Karen, I love it. Brilliant project.
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Old 23rd Apr 2019, 9:20 pm   #8
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Default Re: My 'ASR 33' terminal

The first host for my 'ASR 33 terminal' is shown below - a NIBL BASIC computer running under an SC/MP emulation implemented on a PIC.

I've made NIBL computers like this before, but this one is a bit special. In the past I have implemented serial I/O in PIC code, and exchanged characters with NIBL by creation of extra SC/MP pseudo instructions. This one implements the serial routines in SC/MP code, exactly like the original NIBL system. The PIC implements a cycle perfect emulation to accomplish this.

In fact, the PIC can be used as an SC/MP in itself, though it is nowhere near pin compatible. It can address 64K using its port pins. I've only used 32K of this space to access a 32K static RAM. I've arranged that the NIBL interpreter is copied into low RAM during initialisation. It is then write protected.

Anyway, the upshot is that this computer can list very much faster than it can load. So if I just play back its own listing to it, it will fall way, way behind. I was hoping I could simply suppress the line feed characters to provide an adequate pause between lines, but it is not enough. NIBL requires between 310msec and 520msec to load a new line!

In original application, NIBL used one of its flags to control a 'reader relay' in a teletype. This enabled the paper tape reader to be stopped while NIBL digests each line that is loaded. There is no way I'm going to make a cassette mechanism 'stop on a sixpence' like that so... I am adding a playback FIFO. I will use the reader relay flag as a hardware flow control signal, rather like RTS is used in RTS/CTS handshake that became standard (though departing from the original intention of these control lines).

So, I'm building something almost as sophisticated as the NIBL computer itself to prevent overrunning it during cassette playback! But I've convinced myself that there is a higher purpose here. Either that or I have truly gone over the edge!
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Old 25th Apr 2019, 7:33 pm   #9
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Default Re: My 'ASR 33' terminal

Ah ha - SC/MP - my first 'toe in the water' computer back in the 1970's

I have a skeletal paper tape reader if anyone wants it for the price of the postage - also rather a lot of 1" paper tape

(email me as I don't come here every day andrew <at> mawson <dot> org <dot> uk )
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Old 25th Apr 2019, 7:55 pm   #10
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Default Re: My 'ASR 33' terminal

Have same pictures
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Old 26th Apr 2019, 10:02 am   #11
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Default Re: My 'ASR 33' terminal

The tape reader has now been re-homed - so that's one more bit of junk disposed of - thanks Karen
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Old 26th Apr 2019, 1:43 pm   #12
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Default Re: My 'ASR 33' terminal

Quote:
Originally Posted by Karen O View Post
But I've convinced myself that there is a higher purpose here. Either that or I have truly gone over the edge!

Wenlock, perhaps?
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Old 26th Apr 2019, 2:13 pm   #13
dominicbeesley
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Default Re: My 'ASR 33' terminal

Ah too slow! I've been after a tape reader for a while now. If anyone else has one kicking about I'd me interested - though Karen can probably make more immediate use of it!

D
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Old 16th May 2019, 12:45 am   #14
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Default Re: My 'ASR 33' terminal

I remember "back in the day" that computers could be made to outout NUL (0x00) characters after the linefeed during listing to allow the computer time to process the line. I suppose you could try this, if its possible to get the sc/mp to ignore NUL characters and not lose sync with the serial stream.
On the DG Nova I used at school there was a seperate PUNCH command that acted exactly like LIST except it punced out the NUL characters. Perhaps you could add a command to NIBL to wait a half second between lines?
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