sibo-playground/code/inventory/scan.c

/*
 * scan.c - Phase 1 barcode diagnostic: decoded laser over the serial port.
 *
 * The Workabout MX integral laser powered up and gave a good-read LED on
 * TTY:D, i.e. it is a DECODED scanner that emits ASCII over the serial port -
 * no BAR: decoder LDD needed. The earlier TTY:D read returned nothing because
 * the port's default handshake sets P_OBEY_DSR, and the I/O Devices Reference
 * states that if the remote device does not assert DSR, an outstanding P_FREAD
 * is suspended. The laser does not drive DSR, so the read blocked forever.
 *
 * This build opens TTY:D, applies a P_SRCHAR config at 9600/8/1 with P_OBEY_DSR
 * cleared (P_IGN_CTS only, so reads are not gated on modem lines), forces DTR
 * active, then dumps every byte of each read so the decoded UPC format is seen.
 *
 * Blocking I/O; exit via the System screen.
 */
#include <plib.h>
#include <p_serial.h>

GLDEF_C INT main(VOID)
{
    VOID    *chan;
    P_SRCHAR ser;
    UBYTE    buf[64];
    UBYTE    ctrl[2];
    INT      err, n, i;

    err = p_open(&chan, "TTY:D", (UINT)-1);
    p_printf("open TTY:D: %d\n", err);
    if (err < 0) {
        p_printf("Press a key to exit.\n");
        p_getch();
        return 1;
    }

    /* 9600 baud, 8 data bits, 1 stop, no parity; do NOT obey DSR/DCD (only
       ignore CTS) so a scanner that leaves the modem lines idle can be read. */
    ser.tbaud  = P_BAUD_9600;
    ser.rbaud  = P_BAUD_9600;
    ser.frame  = P_DATA_8;
    ser.parity = 0;
    ser.hand   = P_IGN_CTS;
    ser.xon    = 0x11;
    ser.xoff   = 0x13;
    ser.flags  = 0;
    ser.tmask  = 0;
    err = p_iow(chan, P_FSET, &ser);
    p_printf("config 9600/8/1: %d\n", err);

    /* Force DTR (the scanner enable line) active. Opening already drives it,
       but make it explicit. ctrl[0] is the read-back of input lines. */
    ctrl[0] = 0;
    ctrl[1] = P_SRDTR_ON;
    err = p_iow(chan, P_FCTRL, ctrl);
    p_printf("assert DTR: %d\n", err);

    p_printf("\nScan a barcode. System screen to exit.\n\n");

    /* Read ONE byte per call: with tmask=0 a multi-byte P_FREAD waits for the
       full requested count and would block on a short scan. Streaming single
       bytes returns each character as it arrives, whatever the terminator. */
    for (;;) {
        n = p_read(chan, buf, 1);
        if (n < 0) {
            p_printf("<err %d>", n);
            continue;
        }
        if (n == 0)
            continue;
        i = buf[0];
        p_printf(" %d", i);
        if (i == 13 || i == 10)
            p_printf(" <EOL>\n");
    }
}