| Posted By
Pastbytes
on 2020-12-09
19:05:19
|  Microterm 264, PETSCII terminal for the Plus/4
A few months ago we presented Retroterm, a terminal for Commodore 64 that allows to connect both to C64 (PETSCII) BBS and our new TURBO56K BBS, at 57600 bps. Since my wifi modem can also be used with other Commodore machines with a user port, such as the VIC20 or the Plus/4 (the C16 does not have a user port), I wanted to try some terminal programs to connect to PETSCII BBS at 19200 bps.
Unfortunately I could not find a terminal supporting PETSCII at 19200 bps, so I decided to port a reduced version of Retroterm to the Plus/4. The Commodore Plus/4, unlike the C64, has an ACIA 6551 chip that can perform RS232 communication at speeds up to 19200 bps. This makes it an ideal machine for communications.
Since years ago I decided to make a program for each machine I own, or at least for 8-bit ones, it seemed like a good opportunity to program for the Plus/4. We already had a version of Retroterm that uses the Turbo232 cartridge, which is a variation of Swiftlink, both cartridges that use an ACIA 6551, so we just had to make a few changes, and Microterm 264 was born.
Microterm is essentially Retroterm without TURBO56K commands, using the ACIA 6551 code from the Swiftlink version, modified for the memory map of the Plus/4, and using the VIC II palette.
In this video you can see Microterm connecting to two C64 BBS using the wifi modem, at 19200 bps.
https://www.youtube.com/watch?v=13a3NnKFxyE
More about Retroterm and the TURBO56K protocol (video in Spanish with English subtitles):
https://www.youtube.com/watch?v=13a3NnKFxyE
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Posted By
Gaia
on 2020-12-11
15:58:46
| Re: Microterm 264, PETSCII terminal for the Plus/4
I must admit I never used terminals for 8-bit machines but this is really cool! Thanks for the port, if only this had arrived in 1985...! 
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Posted By
Pastbytes
on 2020-12-14
01:00:01
| Re: Microterm 264, PETSCII terminal for the Plus/4
Thanks!
The sound is not necessary in a terminal, but I always wanted a terminal like the one in the movie War Games.
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Posted By
gerliczer
on 2020-12-14
04:17:29
| Re: Microterm 264, PETSCII terminal for the Plus/4
Interesting. But why is the same video linked twice and where is the programme for those who would be willing to give it a try?
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Posted By
Pastbytes
on 2020-12-14
04:48:13
| Re: Microterm 264, PETSCII terminal for the Plus/4
I didn't realize I pasted the same link twice. It should read:
More about Retroterm and the TURBO56K protocol (video in Spanish with English subtitles):
https://www.youtube.com/watch?v=QD8PH-53vLA
You can download the current version of Microterm here: http://www.pastbytes.com/microterm/microterm3.prg
It always work at 19200 bps, so if you have a modem or RS232 device, you should configure it to use that speed before to run Microterm.
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Posted By
Luca
on 2020-12-14
06:31:14
 | Re: Microterm 264, PETSCII terminal for the Plus/4
Microterm 264 is up, ready tobe linked to the forthcoming related hardware
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Posted By
Pastbytes
on 2020-12-14
06:43:12
| Re: Microterm 264, PETSCII terminal for the Plus/4
I use a wifi modem for C64, with the firmware zimodem from Bo Zimmerman. Some C64 modems should work, at 19200 bps.
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Posted By
Pastbytes
on 2021-01-05
01:13:26
| Re: Microterm 264, PETSCII terminal for the Plus/4
This is the modem I use, compatible with C64, C128, Plus/4 and VIC-20. however I did not test it with the VIC-20.
prg version (Plus/4): http://www.pastbytes.com/microterm/wifimodem+4.prg
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Posted By
Retroshire
on 2021-01-28
06:31:30
| Re: Microterm 264, PETSCII terminal for the Plus/4
Can somebody design a nice gerberfile of this modem and upload it to PCBway?
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Posted By
StormLord
on 2021-01-31
08:26:18
| Re: Microterm 264, PETSCII terminal for the Plus/4
I'm trying to use microterm with my strikelink wifi modem but to no avail.
I prepared the modem to 19200 from my C64 and disabled UP9200 hack by cutting the appropriate line but when I load microterm the keyboard does not respond, when I reset the esp8266 I do get some garbage characters on the screen so there is communication, but maybe the speed is not correct.
Maybe the strikelink firmware can't go up to 19200 even though on the C64 it seems to change the speed and then the characters are displayed wrong?
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Posted By
StormLord
on 2021-01-31
12:21:10
| Re: Microterm 264, PETSCII terminal for the Plus/4
I just flashed the modem with bo zimmerman firmware, but it defaults to 1200bps so I can't configure it from microterm. IS there a way to start the program with different baud settings? So to be able to configure the modem.
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Posted By
Pastbytes
on 2021-02-01
00:10:56
| Re: Microterm 264, PETSCII terminal for the Plus/4
You can use any terminal to change to 19200 bps, I used Higgy Term, the command is atb19200
If you want to save the settings, add &w, but I think it's better to change to 19200 without saving and without turning off the Plus/4, so you can be sure it works. If everything works ok, then you can type at&w in Microterm.
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Posted By
StormLord
on 2021-02-03
19:51:06
| Re: Microterm 264, PETSCII terminal for the Plus/4
I actually changed the default speed from firmware before flashing it and it did "almost" the trick.
My next problem was that microterm is crashing when I try the at+config command, and I have to reset the +4 reload the microterm and on blind continue the next step of the config, then again reset/reload next part of config. At the end I just save it with at&w and I managed to connect to rapid fire successfully. But I've find it really bothersome to config it.
After that everything was perfect, of course there is no protocol for download/upload, but I at least I can read and write my messages to boards with a proper keyboard unlike my breadbin 
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Posted By
Retroshire
on 2021-02-04
03:20:48
| Re: Microterm 264, PETSCII terminal for the Plus/4
@Pastbytes: where can I find gerberfiles of this PCB? Is there an equivalent name of a wifimodemtype?
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