Re: Serial Communication: HB -> Win95 To answer my own question, at least partially, here is a Win95 Host program to communicate (single bytes) with the HandyBoard over a serial line: /* Win95 Visual C++ Host Code to talk to HandyBoard */ #include  // _outp, _inp #include  // sleep #include  // printf unsigned short PORT = 0x3f8; // COM1: 0x3f8 on my computer int send(char c) {         return _outp( PORT, c); } char receive() {         char retval;         retval = _inp( PORT);         _sleep(50);                  // this was necessary; too fast a machine?         retval = _inp( PORT);         return retval; } void main(int argc, char *argv[]) {         char c;         char key = ' ';         while (key != 'q') {                 key = getch();                 send(key);                 printf("Sent %c\\n", key);                  c = receive();                 printf("Got %c as a return value\\n", c);         } } Here is a sample HB program to talk to: void disable_pcode_serial()    /* necessary to receive characters using serial_getchar */ {    poke(0x3c, 1); } void reenable_pcode_serial()    /* necessary for IC to interact with board again */ {    poke(0x3c, 0); } /* ====================================================================== For sending and receiving single bytes, you can use Randy's IC code: */ void serial_putchar(int c) {    while (!(peek(0x102e) & 0x80));  /* wait until serial transmit empty */    poke(0x102f, c);  /* send character */ } int serial_getchar() {    while (!(peek(0x102e) & 0x20)); /* wait for received character */    return peek(0x102f); } void main(void) {         char c = ' ';         disable_pcode_serial();            while (c != 'q') {                 c = serial_getchar();                 printf("\\nReceived = %c   ", c);                  if (c == '1') {                         serial_putchar(analog(0));                 } else if (c == 'a') {                         serial_putchar(knob());                 }                              }         reenable_pcode_serial();            printf("\\nHB Mode!"); } If anyone has a better solution, please let me know. -Doug Blank Douglas Blank wrote:   > I am using the serial_putchar() and serial_getchar() communication routines > on the HandyBoard, and everything is working fine from the PC to the HB. > However, I am having trouble getting the HB to send data back to the PC. ===================================================================== dblank@comp.uark.edu            Douglas Blank, University of Arkansas Assistant Professor                                  Computer Science ==================== http://www.uark.edu/~dblank ====================