/*** LISTING 1 ***/ /*** ***/ /*** serial.h ***/ #include #define COM1 0 #define COM2 1 #define COM3 2 #define COM4 3 #define COM1BASE 0x3F8 /* Base address for COM1 */ #define COM2BASE 0x2F8 /* Base address for COM2 */ #define COM3BASE 0x3E8 /* Base address for COM3 */ #define COM4BASE 0X2E8 /* Base address for COM4 */ /*** ****************************************** ***/ /*** 8250 UART user accessible registers ***/ /*** offsets relative to COMBASE address. ***/ /*** ****************************************** ***/ #define TXR 0 /* Transmit register (WRITE) */ #define RXR 0 /* Receive register (READ) */ #define IER 1 /* Interrupt Enable */ #define IIR 2 /* Interrupt ID */ #define LCR 3 /* Line control */ #define MCR 4 /* Modem control */ #define LSR 5 /* Line Status */ #define MSR 6 /* Modem Status */ #define SRP 7 /* Scratch Pad */ #define DLL 0 /* Divisor Latch Low */ #define DLH 1 /* Divisor latch High */ /*** ****************************************** ***/ /*** INTERRUPT ENABLE REGISTER (OFFSET 1) ***/ /*** ****************************************** ** Bit values of the Interrupt Enable Register (IER). bit meaning --- ------- 0 Interrupt when byte is recieved. 1 Interrupt when transmitter hold- ing register is empty. 2 Interrupt when there is an error in data reception. 3 Interrupt when any RS-232 inputs change states. 4-7 Not used. (Always 0) */ #define RX_INT 0x01 #define TBE_INT 0x02 #define ERR_INT 0x03 #define RS_INT 0x04 /*** ***************************************** ***/ /* INTERRUPT IDENTIFICATION REGISTER (OFFSET 2) */ /*** ***************************************** ** Bit values of the Interrupt Identification (IIR). bit meaning --- ------- 0 0 = Interrupt pending. 1-2 Interrupt ID code 00 = RS-232 input 01 = Transmitter buffer empty 10 = Data received (RX_ID) 11 = Reception error, or BREAK. 3-7 Not used. */ #define RX_ID 0x04 #define RX_MASK 0x07 /*** ***************************************** ***/ /*** LINE CONTROL REGISTER (OFFSET 3) ***/ /*** ***************************************** ** Bit values of the Line Control Register (LCR). bit meaning --- ------- 0-1 00 = 5 bits 01 = 6 bits 10 = 7 bits 11 = 8 bits. 2 Stop bits. 3 0 = parity off 1 = parity on. 4 0 = parity odd 1 = parity even. 5 Sticky parity. 6 Set break. 7 Toggle port addresses. (DLAB) */ #define NO_PARITY 0x00 #define EVEN_PARITY 0x18 #define ODD_PARITY 0x08 #define DLAB 0x80 /*** ***************************************** ***/ /*** MODEM CONTROL REGISTER (OFFSET 4) ***/ /*** ***************************************** ** Bit values of the Modem Control Register (MCR). bit meaning --- ------- 0 1 assert DTR (Data Terminal Ready) 1 1 assert RTS (Request to Send) 2 User definable output. (GPO1) 3 Enable Interrupts on 8250. (GPO2) 4 Local Loopback Test. 5-7 Not used. (Always 0) */ #define DTR 0x01 #define RTS 0x02 #define GPO1 0x04 #define GPO2 0x08 #define EN_INT 0x08 /*** ***************************************** ***/ /*** LINE STATUS REGISTER (OFFSET 5) ***/ /*** ***************************************** ** Bit values held in the Line Status Register (LSR). bit meaning --- ------- 0 Data ready. 1 Overrun error. 2 Parity error. 3 Framing error. 4 Break detect. 5 Transmitter buffer empty. 6 Transmitter empty. 7 Time out. */ #define RCVRDY 0x01 #define OVRERR 0x02 #define PRTYERR 0x04 #define FRMERR 0x08 #define BRKERR 0x10 #define XMTRDY 0x20 #define XMTRSR 0x40 #define TIMEOUT 0x80 /*** ***************************************** ***/ /*** MODEM STATUS REGISTER (OFFSET 6) ***/ /*** ***************************************** ** Bit values held in the Modem Status Register (MSR). bit meaning --- ------- 0 Delta CTS. 1 Delta DSR. 2 Delta RI. 3 Delta DCD. 4 CTS (Clear to Send). 5 DSR (Data Set Ready). 6 RI (Ring indicator). 7 DCD (Data Carrier Detected). */ #define D_CTS 0x01 #define D_DSR 0x02 #define D_RI 0x04 #define D_DCD 0x08 #define CTS 0x10 #define DSR 0x20 #define RI 0x40 #define DCD 0x80 /*** ***************************************** ***/ /*** SCRATCH PAD REGISTER (OFFSET 7) ***/ /*** ***************************************** ** This register has no function and may be use as any other byte of RAM, but note that this register does not exist on early versions of the 8250. */ /*** ***************************************** ***/ /*** LSB & MSB BAUD RATE DIVISOR LATCH ***/ /*** (REGISTER 8 & 9) ***/ /*** ***************************************** ** These two register are use to generate the baud rates. They are reached by setting the DLAB bit of the LINE CONTROL REGISTER to a one and addressing Register 8 as an OFFSET of 0 and Register 9 as an OFFSET of 1. */ /*** ***************************************** ***/ /*** These are the port addresses of the 8259 ***/ /*** Programmable Interrupt Controller (PIC). ***/ /*** ***************************************** ***/ #define IMR 0x21 /* Interrupt Mask Register Port*/ #define ICR 0x20 /* Interrupt Control Port */ /*** An end of interrupt needs to be sent to ***/ /*** the Control Port of the 8259 when a ***/ /*** hardware interrupt ends. ***/ #define EOI 0x20 /* End Of Interrupt */ /*** The (IMR) tells the (PIC) to service an ***/ /*** interrupt only if it is not masked (FALSE).**/ /*** ***************************************** ***/ /*** INTERRUPT ADDRESS FOR COM PORTS ***/ /*** ***************************************** ***/ #define IRQ4 0xEF /*** COM1 & COM3 ***/ #define IRQ3 0xF7 /*** COM2 & COM4 ***/ /*** ***************************************** ***/ /*** GENERAL DEFINE STATEMENTS ***/ /*** ***************************************** ***/ #define SBUFSIZ 4000 /*** ***************************************** ***/ /*** PROTOTYPES ***/ /*** ***************************************** ***/ int SerialOut(char Char_Value); int SerialIn(void); void interrupt far ReceiveData(void); int IntSerialIn(void); int SetPort (int ComPort); int SetBaud(long Baud); int SetOthers(int Parity, int DataBits, int StopBits); int SetSerial(int ComPort, long Baud, int Parity, int DataBits, int StopBits); void Setvects(int ComPort); void Resvects(int ComPort); void EnableInt(int ComPort); void DisableInt(void); void InitSerial(int ComPort); void CloseSerial(int ComPort); void Assert(int request); void Assert_Off(int request); int Status(int request);