Additional Commands for R: Devices

In addition to the Atari 850 command set for R:, there are a few additional commands that have been added to the R: (0x50-0x53) devices.

$44 - Turn on/off Modem Sniffer

When enabled, both incoming and outgoing MODEM traffic are logged to a file called /modem_sniffer.txt on the SD card.

Value	Description
DDEVIC	$50
DUNIT	$01 (Typically $01 for R1:)
DCOMND	$44 'D'
DSTATS	$00 (no payload)
DBUF	NULL (no buffer, because no payload)
DTIMLO	$0F
DBYT	$00 (no bytes, because no payload)
DAUX1	$XX (1=on, 0=off)
DAUX2	$00

$4C - Listen

Listen for TCP connections on the desired TCP port specified by aux1/aux2 (1-65535), If a port is already bound, it will be closed, and the new port specified will be bound for listening.

Value	Description
DDEVIC	$50
DUNIT	$01 (Typically $01 for R1:)
DCOMND	$4C
DSTATS	$00 (no payload)
DBUF	NULL (no buffer, because no payload)
DTIMLO	$0F
DBYT	$00 (no bytes, because no payload)
DAUX1	$LL (The low byte of the 16-bit TCP port number)
DAUX2	$HH (The high byte of the 16-bit TCP port number)

Return

If the port is opened successfully, a COMPLETE will be returned, otherwise an ERROR will result.

$4D - Unlisten

Shut down the listening socket enabled by the above LISTEN command. This will also stop any current client connection.

Value	Description
DDEVIC	$50
DUNIT	$01 (Typically $01 for R1:)
DCOMND	$4D
DSTATS	$00 (no payload)
DBUF	NULL (no buffer, because no payload)
DTIMLO	$0F
DBYT	$00 (no bytes, because no payload)
DAUX1	$00
DAUX2	$00

Return

This command will always return a COMPLETE.

$4E - Lock Baud Rate

Used after a CONFIGURE command to toggle whether to react to baud rate changes. If DAUX1=1 then any baud rate changes received via the CONFIGURE command are ignored, with a COMPLETE sent. Setting DAUX1=0 will resume normal behavior. This can be used to prevent the Atari from changing baud rate, beneficial for BBS use.

Value	Description
DDEVIC	$50
DUNIT	$01 (Typically $01 for R1:)
DCOMND	$4E
DSTATS	$00 (no payload)
DBUF	NULL (no buffer, because no payload)
DTIMLO	$0F
DBYT	$00 (no bytes, because no payload)
DAUX1	$TT ($01 = lock baud rate to prevent further changes)
DAUX2	$00

Return

This command will always return a COMPLETE.

RLISTEN.COM Example

This piece of C code shows how to set a listening port for the R: device.

/**
 * FujiNet Tools for CLI
 *
 * rlisten - Enable TCP port XXXX for listening
 *
 * usage:
 *  rlisten <port#>
 *
 * Author: Thomas Cherryhomes
 *  <thom.cherryhomes@gmail.com>
 *
 * Released under GPL, see COPYING
 * for details
 */

#include <atari.h>
#include <string.h>
#include <stdlib.h>
#include "sio.h"
#include "conio.h"
#include "err.h"

unsigned char buf[40];
unsigned short port;

/**
 * SIO command to set R: listening port
 */
unsigned char listen_port(unsigned short port)
{
  OS.dcb.ddevic=0x50;
  OS.dcb.dunit=1;
  OS.dcb.dcomnd='L';
  OS.dcb.dstats=0x00;
  OS.dcb.dbuf=NULL;
  OS.dcb.dtimlo=0x01;
  OS.dcb.dbyt=0;
  OS.dcb.daux=port;

  siov();

  if (OS.dcb.dstats!=1)
    err_sio();

  return OS.dcb.dstats;
}

/**
 * show options
 */
void opts(char* argv[])
{
  print(argv[0]);
  print(" <port#>\x9b\x9b");
  print("<port#> - TCP Port # (1-65535)\x9b");
}

/**
 * main
 */
int main(int argc, char* argv[])
{
  unsigned char err=0;

  OS.lmargn=2;

  if (_is_cmdline_dos())
    {
      if (argc<2)
        {
          opts(argv);
          return(1);
        }
      port=atoi(argv[1]);
    }
  else
    {
      // DOS 2.0/MYDOS
      print("\x9b");

      print("LISTEN TO WHICH PORT? ");
      get_line(buf,sizeof(buf));
      port=atoi(buf);
    }

  if (port<1)
    {
      print("INVALID PORT NUMBER.\x9b");
      return(1);
    }

  err=listen_port(port);

  if (!_is_cmdline_dos())
    {
      print("\x9bPRESS \xD2\xC5\xD4\xD5\xD2\xCE TO CONTINUE.\x9b");
      get_line(buf,sizeof(buf));
    }

  return(err);
}