KEPCO BIT 232F - Manual (Page 65)

BIT 232 022800
F-1
APPENDIX F - C LANGUAGE FUNCTIONS
F.1 INTRODUCTION
This appendix contains examples of C language functions which can be used as the building
blocks for unique programs to interface the BIT Card and associated power supply with an IBM-
PC-compatible computer. These functions are used in the sample programs shown in Appendi-
ces D and E.
F.2 OPEN SERIAL PORT USING ROM BIOS ROUTINE
This function opens the serial port selected by n, using the ROM BIOS routine; if the computer is
not IBM-PC-compatible the ROM BIOS routine must be replaced by an equivalent.
/* open serial port using ROM BIOS routine */
void open_port(int n)
{
union REGS regs;
/* AH has the function code */
regs.h.ah = 0x00;
/* AL has the baud rate for 8 bits No parity 1 Stop bit */
regs.h.al = 0xe3;
/* DX has the port number */
if (n == 1)
regs.x.dx = 0;
else
regs.x.dx = 1;
/* call the ROM BIOS routine */
int86(0x14, ®s, ®s);
}
F.3 PUT CHARACTER TO SERIAL PORT
This function sends a character (c) to the serial port specified by (n) using the ROM BIOS rou-
tine; if the computer is not IBM-PC-compatible the ROM BIOS routine must be replaced by an
equivalent.
/* put character to serial port */
void put_serc(int n, int c)
{
union REGS regs;
/* AH has the function code */
regs.h.ah = 0x01;
/* AL has the character */
regs.h.al = c;
/* DX has the port number */
if (n == 1)
regs.x.dx = 0;
else
regs.x.dx = 1;
/* call the ROM BIOS routine */
int86(0x14, ®s, ®s);
}