From: Richard B. Gilbert [76702.1567@compuserve.com]
Sent: Friday, September 03, 1999 12:33 AM
To: Info-VAX@Mvb.Saic.Com
Subject: Setting RTS/CTS signals
Message text written by INTERNET:maltenbe@debis.com
>I want to develop a driver for the serial-line on a VAX (VMS5.5-2) in
the programming language "C". How can I set the RTS/CTS signals for the
hardwarehandshake? I'm working with 1200 bit/sec and halfduplex.
<
Well, you *can't* set CTS!
Here's an example program that may illustrate how to turn on, or
off, the signals that you can turn on and off.
/*
Copyright 1995
Richard B. Gilbert
All rights reserved.
<76702.1567@CompuServe.Com>
This program is intended to be used with a breakout box to
determine
the signals that are supported by a serial port. The program translates
the
logical name TEST_DEVICE to determine name of the serial port you want to
test.
First it determines what sort of controller you are dealing with.
It
recognizes and reports: DZ11, DZ32, DMF32, DMB32, DMZ32, DHV-11, DHU-11,
and LAT; otherwise it reports "Unknown". OPAn: ports will most likely
be reported as Unknown.
It sets DTR, RTS and Secondary Tx. It then reports the signals it
sees from the set: DSR, RING, Carrier Detect, CTS and SECREC. Use a
breakout box to force these signals true in order to determine which of
them
can actually be detected. After a one second pause, it turns of DTR, RTS
secondary Tx, then senses and reports the input signals again.
If you don't have a breakout box, you can use a loopback connector
that connects DTR to DSR, CD, and RING; RTS to CTS; and SecTX to SecRec.
*/
#if defined __DECC
#pragma message disable dollarid
#endif
#include <stdio.h>
#include <stdlib.h>
#include <descrip.h>
#include <signal.h>
#include <starlet.h>
#include <iodef.h>
#include <ttdef.h>
#include <dcdef.h>
#include <lib$routines.h>
int main(int argc, char **argv);
void list_modem_signals(char);
int main(int argc, char **argv)
{
struct {
unsigned short cond_val;
unsigned short count;
unsigned long device_specific;
} iosb;
struct {
char reserved_1;
char reserved_2;
char modem_on;
char modem_off;
char filler[4];
} set_mode_p1;
struct {
char controller_type;
char reserved_3;
char receive_modem;
char filler_2[9];
} sense_mode_p1;
struct set_mode_buffer
{
char class;
char type;
short buffer_size;
long basic_chars;
long extended_char;
};
struct set_mode_buffer mode_buffer, nomodem_mode;
static $DESCRIPTOR(port_desc, "TEST_DEVICE");
unsigned long ret_status, io_func;
unsigned short chan;
printf(" Copyright 1995.\n Richard B. Gilbert\n All rights
reserved.\n");
ret_status = sys$assign(&port_desc, &chan, 0, 0, 0);
/*
Save the port characteristics for later.
*/
ret_status = sys$qiow(0, chan, IO$_SENSEMODE, &iosb, 0, 0,
&mode_buffer, sizeof(mode_buffer), 0, 0, 0, 0);
/*
Learn what sort of controller we are dealing with.
*/
io_func = IO$_SENSEMODE | IO$M_RD_MODEM;
ret_status = sys$qiow(0, chan, io_func, &iosb, 0, 0,
&sense_mode_p1, sizeof(sense_mode_p1), 0, 0, 0, 0);
if ((ret_status & 7) != 1) lib$stop(ret_status);
if ((iosb.cond_val & 7) !=1) lib$signal(iosb.cond_val);
printf("\n Controller type is ");
switch (sense_mode_p1.controller_type)
{
case DT$_DZ11: printf("DZ11\n");
break;
case DT$_DZ32: printf("DZ32\n");
break;
case DT$_DMF32: printf("DMF32\n");
break;
case DT$_DMB32: printf("DMB32\n");
break;
case DT$_DMZ32: printf("DMZ32\n");
break;
case DT$_DHV: printf("DHV-11\n");
break;
case DT$_DHU: printf("DHU-11\n");
break;
case DT$_LAT: printf("LAT\n");
break;
default: printf("Unknown (%d)\n",
sense_mode_p1.controller_type);
}
list_modem_signals(sense_mode_p1.receive_modem);
/*
Set the port /NOMODEM.
*/
nomodem_mode = mode_buffer;
nomodem_mode.basic_chars = mode_buffer.basic_chars & (!TT$M_MODEM);
ret_status = sys$qiow(0, chan, IO$_SETMODE, &iosb, 0, 0,
&nomodem_mode, sizeof(nomodem_mode), 0, 0, 0, 0);
/*
Turn on RTS, DTR and Secondary TX.
*/
printf(" Turning on RTS, DTR and Secondary Tx\n");
set_mode_p1.modem_on = TT$M_DS_RTS | TT$M_DS_DTR | TT$M_DS_SECTX;
ret_status = sys$qiow(0, chan, IO$_SETMODE | IO$M_SET_MODEM |
IO$M_MAINT,
&iosb, 0, 0, &set_mode_p1, 0, 0, 0, 0, 0);
if ((ret_status & 7) != 1) lib$stop(ret_status);
if ((iosb.cond_val & 7) !=1) lib$signal(iosb.cond_val);
#pragma nostandard
sleep(1);
#pragma standard
ret_status = sys$qiow(0, chan, IO$_SENSEMODE | IO$M_RD_MODEM,
&iosb, 0, 0, &sense_mode_p1, 0, 0, 0, 0, 0);
if ((ret_status & 7) != 1) lib$stop(ret_status);
if ((iosb.cond_val & 7) != 1) lib$signal(iosb.cond_val);
list_modem_signals(sense_mode_p1.receive_modem);
sleep(5);
/*
Turn off RTS, DTR, and Secondary TX.
*/
printf(" Turning off RTS, DTR and Secondary Tx\n");
set_mode_p1.modem_on = 0;
set_mode_p1.modem_off = TT$M_DS_RTS | TT$M_DS_DTR | TT$M_DS_SECTX;
ret_status = sys$qiow(0, chan, IO$_SETMODE | IO$M_SET_MODEM |
IO$M_MAINT,
&iosb, 0, 0, &set_mode_p1, 0, 0, 0, 0, 0);
if ((ret_status & 7) != 1) lib$stop(ret_status);
if ((iosb.cond_val & 7) != 1) lib$signal(iosb.cond_val);
sleep(1);
sense_mode_p1.receive_modem = 0;
ret_status = sys$qiow(0, chan, IO$_SENSEMODE | IO$M_RD_MODEM,
&iosb, 0, 0, &sense_mode_p1, 0, 0, 0, 0, 0);
if ((ret_status & 7) != 1) lib$stop(ret_status);
if ((iosb.cond_val & 7) != 1) lib$signal(iosb.cond_val);
list_modem_signals(sense_mode_p1.receive_modem);
/*
Restore the port to the way we found it.
*/
ret_status = sys$qiow(0, chan, IO$_SETMODE, &iosb, 0, 0,
&mode_buffer, 0, 0, 0, 0, 0);
exit(1);
}
void list_modem_signals(char receive_modem)
{
printf("\n");
if ((receive_modem & TT$M_DS_DSR) != 0) printf("DSR ");
if ((receive_modem & TT$M_DS_RING) != 0) printf("RING ");
if ((receive_modem & TT$M_DS_CARRIER) != 0) printf("CARRIER ");
if ((receive_modem & TT$M_DS_CTS) != 0) printf("CTS ");
if ((receive_modem & TT$M_DS_SECREC) != 0) printf("SECREC ");
printf("\n");
}