[Coco] Bit-Banger Serial as external console?

[Stephen Pereira]

Hello again, folks,

I took Arthur’s advice and started looking for BBS code.  I ended up looking at an article in the November 1983 Rainbow titled “Remote Operation of the Color Computer”.  It has exactly what I think I need.  The tiny assembly language program installs input & output from a remote terminal along with the normal keyboard and screen.  When running, a person at the remote terminal can operate the CoCo as if they were directly on the system.

Of course, the trouble is that the program does not work for me on my CoCo 3.  The communication gets established, but the actual characters get scrambled in both directions.  I’ve tried 150, 300 and 600 Baud, as well as 1 or 2 stop bits, and 7 or 8 data bits.

I’m concerned that maybe this code cannot work properly on the CoCo 3 because it had not yet arrived?  

Here’s a copy of the code if anyone else would like to try it out.  Please let me know if you are successful!

********************************
*           REMOTE             *
*   A REMOTE TERMINAL DRIVER   *
*        FOR THE COCO          *
* DAN DOWNARD   RAINBOW  11/83 *
********************************
        ORG     $3F00
* EQUATES FOR ROM & RAM ADDRESSES
IHOOK   EQU     $016A
OHOOK   EQU     $0167
PIA     EQU     $FF22
POLCAT  EQU     $A000
RSOUT   EQU     $BE0C
BAUD    EQU     $E6
BAUDR   EQU     $C9
DEV     EQU     $6F
FLAG    EQU     $70
* INITIALIZE RAM HOOKS
START   LDA     #BAUDR
        STA     <BAUD
        LDX     1+OHOOK
        STX     1+ORET2,PCR
        LDX     1+IHOOK
        STX     1+IRET2,PCR
        LDA     #$7E
        STA     IHOOK
        STA     OHOOK
        LEAX    OUT,PCR
        STX     1+OHOOK
        LEAX    IN,PCR
        STX     1+IHOOK
RET     RTS
* OUTPUT CHARACTER IF DEV=0
* INSERT LINE FEED TO REMOTE DEVICE
* USE ROM SUBROUTINE
OUT     PSHS    A
        TST     <DEV
        BNE     ORET1
        CMPA    #$0D
        BNE     REMOUT
        LDA     #$0A
        JSR     RSOUT
        LDA     #$0D
REMOUT  JSR     RSOUT
ORET1   PULS    A
ORET2   JMP     RET
* INPUT FROM KEYBOARD OR RS-232
* IF DEV=0
* USE RSIN FOR REMOTE INPUT
IN      CLR     <FLAG
        TST     <DEV
        BNE     IRET2
        LEAS    2,S
        PSHS    B,CC,X
IN1     JSR     [POLCAT]
        BEQ     REMIN
        BRA     IRET1
* CHECK FOR REMOTE INPUT
REMIN   LDB     $FF22
        RORB
        BCS     IN1
* RS-232 INPUT ROUTINE
* BYTE INTO A REGISTER
RSIN    BSR     HALF
        LDB     #1
        PSHS    B
        CLRA
RSIN1   BSR     FULL
        LDB     PIA
        RORB
        BCC     RSIN2
        ORA     0,S
RSIN2   ASL     0,S
        BCC     RSIN1
        LEAS    1,S
        ANDA    #$7F
IRET1   PULS    B,CC,X,PC
IRET2   JMP     RET
* BAUD RATE DELAYS
FULL    BSR     HALF
HALF    PSHS    A
        LDA     <BAUD
HALF1   BRN     HALF1
        DECA
        BNE     HALF1
        PULS    PC,A
        END     START
        

smp
- - -
Stephen Pereira
Bedford, NH  03110
KB1SXE


> On Mar 26, 2019, at 2:03 PM, Chester A Patterson <vchester at setec-cr.com> wrote:
> 
> Years ago I used Cocos via their bit-bangers to communicate with remote screens connected to scales in production lines. The scale keyboard had three function keys to communicate back to the Coco. So the scale operator interacted with the Coco all day. I enjoyed those projects immensely.  I got the idea because of reading in Rainbow (I think) of some oil drilling site that used a Coco to control the drilling. Ages ago that.
> 
> -----Original Message-----
> From: Stephen Fischer <SFischer1 at Mindspring.com> 
> Sent: Monday, March 25, 2019 9:47 PM
> To: coco at maltedmedia.com
> Subject: Re: [Coco] Bit-Banger Serial as external console?
> 
> 
> It is out of scope for your project,
> 
> But I remember vaguely using OS-9 to log in on another computer using the bit banger on the CoCo.
> 
> If someone can confirm that, the NitrOS-9 source code might be useful to look at.
> 
> It has been 25 +- 10 or more years so my memory is very fuzzy.
> 
> SHF
> 
> 
> 
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