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Personal Communications Library For the C Language (PCL4C) REFERENCE MANUAL Version 3.3 Aug 3, 1992 This software is provided as-is. There are no warranties, expressed or implied. Copyright (C) 1992 All rights reserved MarshallSoft Computing, Inc. Post Office Box 4543 Huntsville AL 35815 Voice 205-881-4630 FAX 205-881-4630 BBS 205-880-9748 PCL4C Reference Manual Page 1 C O N T E N T S Chapter Page Table of Contents.............................2 Introduction..................................3 SioBaud....................................4 SioBrkKey..................................5 SioBrkSig..................................6 SioCrtWrite................................7 SioCTS.....................................8 SioDCD.....................................9 SioDelay..................................10 SioDone...................................11 SioDSR....................................12 SioDTR....................................13 SioError..................................14 SioFIFO...................................15 SioFlow...................................16 SioGetc...................................17 SioKeyPress...............................18 SioKeyRead................................19 SioInfo...................................20 SioIRQ....................................21 SioLine...................................22 SioLoopBack...............................23 SioModem..................................24 SioParms..................................25 SioPutc...................................26 SioRead...................................27 SioReset..................................28 SioRI.....................................29 SioRTS....................................30 SioRxBuf..................................31 SioRxFlush................................32 SioRxQue..................................33 SioTimer..................................34 SioUART...................................35 SioUnGetc.................................36 Function Summary.............................37 Error Code Summary...........................38 PCL4C Reference Manual Page 2 Introduction This manual lists all of the PCL4C functions in alphabetical order. Every library function will return a value as follows: 1. Negative values for error conditions. See last page of this manual for a list of error values and their meanings. 2. Non-negative values when returning data (eg: SioLine). 3. Zero otherwise. When debugging an application, be sure to test all return values. Use SioError to print the associated text for errors. Example Code Segment ***************************************************************** * int Code; /* MUST be 'int', not 'char' */ * * * * Code = SioFunction( ); /* any PCL4C function */ * * if(Code<0) * * {/* error returned */ * * SioError(Code); /* SioError prints error text */ * * SioDone(Port); /* always call SioDone last */ * * exit(1); * * } * * /* no errors */ * * ...your application code... * * * ***************************************************************** For more examples, examine each of the example programs provided SIMPLE.C, TERM.C, INTERCOM.C, NORESET.C, LOOPBACK.C, MODEM.C, (BBS.C, and XFER.C). Also look at the examples associated with each library function described in the following section. Refer the User's Manual (PCL4C.USR) for addition information. PCL4C Reference Manual Page 3 SioBaud Function Sets the baud rate of the selected port. Syntax int SioBaud(Port,BaudCode) int Port; /* Port selected (COM1 - COM4) */ int BaudCode; /* Baud code */ Remarks The SioBaud function sets the baud rate without resetting the port. It is used to change the baud rate after calling SioReset. Baud Code Baud Rate PCL4C.H Name 0 300 Baud300 1 600 Baud600 2 1200 Baud1200 3 2400 Baud2400 4 4800 Baud4800 5 9600 Baud9600 6 19200 Baud19200 7 38400 Baud38400 8 57600 Baud57600 9 115200 Baud115200 Returns -4 : Port out of range. Expected 0 to 3. -11 : Bad baud rate code. See above code values. Example /* do auto baud detect */ for(Code=0;Code<10;Code++) {/* set baud rate & transmit 'A' */ SioBaud(Port,Code); SioPutc(Port,'A'); /* assume other side echos back */ if(SioGetc(Port,18)=='A')) {puts("Baud rate detected"); /*...do something here...*/ } } See Also SioReset PCL4C Reference Manual Page 4 SioBrkKey Function Return non-zero if the Control-BREAK key was pressed. Syntax int SioBrkKey() Remarks The SioBrkKey function returns a TRUE value (non- zero) if the Control-BREAK key was pressed, else it returns a zero. Use SioBrkKey as a safety exit from a polling loop. Don't mix this function up with SioBrkSig. Returns -1 : Control-BREAK was pressed. 0 : Control-BREAK was NOT pressed. Example int c; ... while(1) {/* exit if user pressed Control-BREAK */ if(SioBrkKey()) {puts("User typed Contrl-BREAK"); SioDone(Port); exit(1); } /* transmit any typed character */ if(SioKeyPress()) {c = SioKeyRead(); SioPutc(Port,c); } /* display any incoming character */ c = SioGetc(Port,0); if(c!=-1) SioCrtWrite(c); } See Also SioBrkSig PCL4C Reference Manual Page 5 SioBrkSig Function Asserts, cancels, or detects BREAK signal. Syntax int SioBrkSig(Port,Cmd) int Port; /* Port selected (COM1 thru COM4) */ char Cmd; /* ASSERT, CANCEL, or DETECT */ Remarks The SioBrkSig function controls the BREAK bit in the line status register. The legal commands are: ASSERT ('A') to assert BREAK CANCEL ('C') to cancel BREAK DETECT ('D') to detect BREAK ASSERT, CANCEL, and DETECT are defined in PCL4C.H. See TERM.C for an example of the use of SioBrkSig. Returns -2 : Port not enabled. Call SioReset first. -4 : Port out of range. Expected 0 to 3. -6 : Illegal command. Expected 'A', 'C', or 'D'. >0 : BREAK signal detected (DETECT command only) Example /* Assert BREAK for 1 second */ SioBrkSig(Port,ASSERT); SioDelay(18); SioBrkSig(Port,CANCEL); /* Detect BREAK */ if(SioBrkSig(Port,DETECT)) {puts("BREAK signal detected"); /* ...do some more stuff... */ } See Also SioBrkKey PCL4C Reference Manual Page 6 SioCrtWrite Function Write character to the screen. Syntax int SioCrtWrite(ch) char ch; /* character to write */ Remarks The SioCrtWrite function uses the BIOS to write a single character to the screen at the current cursor location. SioCrtWrite calls the BIOS directly without any intermediate buffering or processing. It is usually faster than a call to the C library. Returns zero Example /* wait up to 1 second (18 tics) for character */ if( (c = SioGetc(COM1,18)) != -1) {/* echo to screen */ SioCrtWrite(c); } See Also SioKeyPress and SioKeyRead PCL4C Reference Manual Page 7 SioCTS Function Reads the Clear to Send (CTS) modem status bit. Syntax int SioCTS(Port) int Port; /* Port selected (COM1 thru COM4) */ Remarks The SioCTS function is used to read the Clear to Send (CTS) modem status bit. The CTS line is used by some error correcting modems to implement hardware flow control. CTS is dropped by the modem to signal the computer not to send data, and is raised to signal the computer to continue. Refer to the User's Manual for a discussion of flow control. Returns -2 : Port not enabled. Call SioReset first. -4 : Port out of range. Expected 0 to 3. 0 : CTS is clear. >0 : CTS is set. Example /* wait for CTS to go active */ while(1) {if(SioCTS(Port)) break; if(SioBrkKey()) {puts("Aborted by user"); SioDone(Port); exit(1); } } /* now we can send the character */ SioPutc(Port,ch); See Also SioFlow, SioDSR, SioRI, SioDCD, and SioModem. PCL4C Reference Manual Page 8 SioDCD Function Reads the Data Carrier Detect (DCD) modem status bit. Syntax int SioDCD(Port) int Port; /* Port selected (COM1 thru COM4) */ Remarks The SioDCD function is used to read the Data Carrier Detect (DCD) modem status bit. Also see SioModem. Returns -2 : Port not enabled. Call SioReset first. -4 : Port out of range. Expected 0 to 3. 0 : DCD is clear. >0 : DCD is set. Example /* test data carrier status bit */ if(SioDCD(Port)) puts("Carrier is on"); else puts("Carrier is off"); See Also SioDSR, SioCTS, SioRI, and SioModem. PCL4C Reference Manual Page 9 SioDelay Function Delays one or more tics. Syntax int SioDelay(tics) int tics; /* # tics */ Remarks The SioDelay function is used to delay one or more timer tics, where each timer tic is approximately 55 milliseconds (18 tics to the second). Returns zero Example /* delay 5 seconds */ SioDelay(5*18); See Also SioTimer PCL4C Reference Manual Page 10 SioDone Function Terminates further serial processing. Syntax int SioDone(Port) int Port; /* Port selected (COM1 thru COM4) */ Remarks The SioDone function terminates further serial processing. SioDone MUST be called before exiting your application so that interrupts can be restored to their original state. Failure to do this can crash the operating system. If you forget to call SioDone before exiting, be sure to re-boot your computer. You can call SioDone even if SioReset has not been called, so it is good practice to always call SioDone before exiting your application. Returns -2 : Port not enabled. Call SioReset first. -4 : Port out of range. Expected 0 to 3. Example /* terminate processing for COM3 */ SioDone(COM3); See Also SioReset. PCL4C Reference Manual Page 11 SioDSR Function Reads the Data Set Ready (DSR) modem status bit. Syntax int SioDSR(Port) int Port; /* Port selected (COM1 thru COM4) */ Remarks The SioDSR function is used to read the Data Set Ready (DSR) modem status bit. Returns -2 : Port not enabled. Call SioReset first. -4 : Port out of range. Expected 0 to 3. 0 : DSR is clear. >0 : DSR is set Example /* read DSR status bit */ if(SioDSR(Port)) puts("Modem is ready"); else puts("Modem is not ready"); See Also SioCTS, SioRI, SioDCD, and SioModem PCL4C Reference Manual Page 12 SioDTR Function Set, clear, or read the Data Terminal Ready (DTR) bit. Syntax int SioDTR(Port,Cmd) int Port; /* Port selected (COM1 thru COM4) */ char Cmd; /* DTR command (SET, CLEAR, or READ) */ Remarks The SioDTR function controls the Data Terminal Ready (DTR) bit in the modem control register. Commands (defined in PCL4C.H) are: SET ('S') to set DTR (ON) CLEAR ('C') to clear DTR (OFF) READ ('R') to read DTR Returns -2 : Port not enabled. Call SioReset first. -4 : Port out of range. Expected 0 to 3. -5 : Not one of 'S', 'C', or 'R'. 0 : DTR is OFF (READ Command). >0 : DTR is ON (READ Command). Example /* turn DTR on for modem connected to COM4 */ SioDTR(COM4,SET); See Also SioRTS. PCL4C Reference Manual Page 13 SioError Function Displays error in text. Syntax int SioError(Code) int Code; /* Error code returned from */ /* a PCL4C function */ Remarks The SioError function displays the error in text corresponding to the error code. During development of a communications application, it is a good idea to always test return codes, and print out their descriptions with SioError. Returns zero Example code = SioReset(Port,Baud4800); /* display error message if error occurred */ if(code<0) SioError(code); PCL4C Reference Manual Page 14 SioFIFO Function Sets the FIFO trigger level (INS16550 only). Syntax int SioFIFO(Port,LevelCode) int Port; /* Port selected (COM1 thru COM4) */ int LevelCode; /* FIFO level code (see below) */ Remarks The SioFIFO function is used to set the trigger level at which interrupts are generated. For example, if the FIFO level is set to 8, then the INS16550 UART will not generate an interrupt until 8 bytes have been received. This reduces the number of interrupts generated and allows faster processing with slower machines or when running simultaneous ports. In order to test if your port is a INS16550, call SioFIFO with a LevelCode of other than FIFO_OFF. SioFIFO can be called for the INS8250/16450 without ill effect. Code PCL4C.H Name Trigger Level -1 FIFO_OFF Disable FIFO 0 LEVEL_1 1 byte 1 LEVEL_4 4 bytes 2 LEVEL_8 8 bytes 3 LEVEL_14 14 bytes Returns -2 : Port not enabled. Call SioReset first. -4 : Port out of range. Expected 0 to 3. >0 : FIFO level set. 0 : FIFO level not set (not INS16550). Example /* Set FIFO level to 8 */ if( SioFIFO(Port,LEVEL_8) ) printf("FIFO reset\n"); else printf("UART in not INS16550\n"); PCL4C Reference Manual Page 15 SioFlow Function Sets hardware (RTS/CTS) flow control. Syntax int SioFlow(Port,Tics) int Port; /* Port selected (COM1 thru COM4) */ int Tics; /* SioPutc timeout tics */ Remarks The SioFlow function is used to enable or disable hardware flow control. Hardware flow control uses RTS and CTS to control data flow between the modem and the computer. Refer to the User's Manual for a discussion of flow control. To enable hardware flow control, call SioFlow with Tics > 0. "Tics" is the number of timer tics (18 per second) before a call to SioPutc will time out because the modem dropped CTS. In order for hardware flow control to work correctly, your modem must also be configured to work with hardware flow control, and your computer to modem cable must have RTS and CTS wired straight through. If you enable hardware flow control, do not modify the RTS line (by calling SioRTS) unless you know exactly what you are doing. Flow control is disabled after resetting a port. To explicitly disable hardware flow control, call SioFlow with Tics = -1. Returns -2 : Port not enabled. Call SioReset first. -4 : Port out of range. Expected 0 to 3. =0 : Flow control disabled. >0 : Flow control enabled. Example /* Enable flow control on COM1 */ Code = SioFlow(COM1,18); if(Code>0) printf("Flow Control enabled\n"); else SioError(Code); /* disable flow control on COM2 */ Code = SioFlow(COM2,-1); if(Code==0) printf("Flow Control disabled\n"); else SioError(Code); See Also SioPutc PCL4C Reference Manual Page 16 SioGetc Function Reads the next character from the serial line. Syntax int SioGetc(Port,Tics) int Port; /* COM1 to COM4 */ int Tics; /* # timer tics */ Remarks The SioGetc function reads a byte from the selected serial port. The function will wait for the number of system tics given by the 'Tics' argument before returning 'timed out'. There are 18 tics to the second. To specify no waiting, call SioGetc with Tics = 0. Returns -2 : Port not enabled. Call SioReset first. -4 : Port out of range. Expecting 0 to 3. -1 : If timed out. >0 : Character read. Example int c; /* MUST be 'int', not 'char' !!! */ ... /* wait 9 tics for incoming character & display it */ if( (c=SioGetc(COM1,9)) != -1) printf("Character is '%c'\n", c); else puts("Timed out"); See Also SioUnGetc and SioPutc. PCL4C Reference Manual Page 17 SioKeyPress Function Detects if keyboard has been pressed. Syntax int SioKeyPress() Remarks The SioKeyPress function uses the BIOS to test the keyboard for a key press (including control characters). SioKeyPress calls the BIOS directly without any intermediate buffering or processing. It is usually faster than using the C library. Returns zero Example if( SioKeyPress() ) {c = SioKeyRead(); /* echo character c */ SioCrtWrite(c) } See Also SioCrtWrite and SioKeyRead. PCL4C Reference Manual Page 18 SioKeyRead Function Reads the keyboard. Syntax int SioKeyRead() Remarks The SioKeyRead function uses the BIOS to read the keyboard. It will wait until a character is typed. SioKeyRead calls the BIOS directly without any intermediate buffering or processing. It is usually faster than using the C library. Returns Character typed (including control codes). Example if(SioKeyPress()) {/* fetch the character */ c = SioKeyRead(); /* echo to screen */ SioCrtWrite(c); } See Also SioCrtWrite and SioKeyRead. PCL4C Reference Manual Page 19 SioInfo Function Returns PCL4C library information. Syntax int SioInfo(Cmd) char Cmd; /* Command (VERSION or MODEL) */ Remarks The SioInfo function returns an integer code corresponding to either the library version number or the memory model that the library was assembled under. SioInfo is provided so that you can verify the library version number and memory model that a PCL4C library was assembled under. Returns VERSION ('V') hex byte XY where version is denoted as X.Y M_MODEL ('M') 0 Small 1 Compact 2 Medium 3 Large Example char *Model[] = {"Small","Compact","Medium","Large"}; char Version; char Model; ... /* display library version */ Version = SioInfo(VERSION); printf("Library version is %d.%d\n", Version/16, Version%16); /* display memory model */ Model = SioInfo(MODEL); printf("Memory Model is %s\n", Model[Code]); PCL4C Reference Manual Page 20 SioIRQ Function Assigns an IRQ line to a port. Syntax int SioIRQ(Port,IRQcode) int Port; /* Port selected (COM1 thru COM4) */ int IRQcode; /* PRIMARY or SECONDARY */ Remarks The SioIRQ function assigns an IRQ line to a port. SioIRQ (like SioUART) must be called before calling SioReset in order to have any effect. Unless you have a non-standard serial port configuration, you will never need to call SioIRQ. IRQ 4 is the standard primary IRQ line while IRQ 3 is the standard secondary IRQ line. The default IRQ codes are thus: Port IRQ Code COM1 PRIMARY COM2 SECONDARY COM3 PRIMARY COM4 SECONDARY The IBM PS/2 uses non-standard COM3 and COM4 port configurations as follows: Port IRQ Code UART COM3 SECONDARY 0x3220 COM4 SECONDARY 0x3228 Returns -2 : Port not enabled. Call SioReset first. -4 : Port out of range. Expecting 0 to 3. 0 : Otherwise Example /* setup PS/2 COM3 port */ SioUART(COM3,0x3220); SioIRQ(COM3,SECONDARY); See Also SioUART. PCL4C Reference Manual Page 21 SioLine Function Reads the line status register. Syntax int SioLine(Port) int Port; /* Port selected (COM1 thru COM4) */ Remarks The SioLine function reads the line status register. The individual bit masks are as follows: 0x20 = Transmitter Buffer Empty. 0x10 = Break detected. 0x08 = Framming error. 0x04 = Parity error. 0x02 = Overrun error. 0x01 = Data ready. The above are documented in the file PCL4C.H. Returns -2 : Port not enabled. Call SioReset first. -4 : Port out of range. Expecting 0 to 3. >0 : Line status (rightmost byte of word). Example int rc; ... rc = LineStatus(Port); if(rc & (FramingError|ParityError|OverrunError)) {if(rc & FramingError) puts("Framing Error"); if(rc & ParityError) puts("Parity Error"); if(rc & OverrunError) puts("Overrun Error"); } else puts("No error"); See Also SioModem. PCL4C Reference Manual Page 22 SioLoopBack Function Does a UART loopback test. Syntax int SioLoopBack(Port) int Port; /* Port selected (COM1 thru COM4) */ Remarks SioLoopBack makes use of the built in loopback test capability of the INS8250 UART. Normally SioLoopBack will never need to be called except if you suspect that your UART is bad. See the LOOPBACK.C program. Returns 0 : Loopback test is successfull. -2 : Port not enabled. Call SioReset first. -4 : Port out of range. Expecting 0 to 3. -12 : Loopback test fails. Example /* test port */ if(SioLoopBack(Port)) puts("Loopback test has failed"); else puts("Loopback test has succeeded"); PCL4C Reference Manual Page 23 SioModem Function Reads the modem status register. Syntax int SioModem(Port, Mask) int Port; /* Port selected (COM1 thru COM4) */ char Mask; /* Modem function mask */ Remarks The SioModem function reads the modem register. The bit definitions for the function mask are as follows: Bit PCL4C.H Name Function 7 DCD Data Carrier Detect 6 RI Ring Indicator 5 DSR Data Set Ready 4 CTS Clear To Send 3 DeltaDCD Delta DCD (DCD has changed) 2 DeltaRI Delta RI (RI has changed) 1 DeltaDSR Delta DSR (DSR has changed) 0 DeltaCTS Delta CTS (CTS has changed) Bits 4 through 7 represent the absolute state of their respective RS-232 inputs. Bits 0 through 3 repesent a change in the state of their respective RS-232 inputs since last read. The above definitions are also in the PCL4C.H file for use by your application program. Returns -2 : Port not enabled. Call SioReset first. -4 : Port out of range. Expecting 0 to 3. >0 : Modem status (rightmost byte of word). Example /* any change in DCD or CTS ? */ if(delta=SioModem(Port,DeltaDCD|DeltaCTS)) {status = SioModem(Port,DCD|CTS); if(delta&DeltaDCD) {if(status&DCD) c='T'; else c='F'; } printf("DCD=%c\n",c); } if(delta&DeltaCTS) {if(status&CTS) {c='T'; else c='F'; printf("CTS=%c\n",c); } } See Also SioCTS, SioDCD, SioDSR and SioRI. PCL4C Reference Manual Page 24 SioParms Function Sets parity, stop bits, and word length. Syntax int SioParms(Port,ParityCode,StopBitsCode,WordLengthCode) int Port; /* Port selected (COM1 thru COM4) */ int ParityCode; /* parity code [0,1,2] */ int StopBitsCode; /* stop bits code [0,1] */ int WordLengthCode; /* word length code [0,1,2,3] */ Remarks The SioParms function sets the parity, stop bits, and word length. If the default parity (none), stop bits (1), or word length (8) is not acceptable, then they can be changed by calling SioParms. SioParms can be called either before or after calling SioReset. See file PCL4C.H. Value Description PCL4C.H Name ParityCode: *0 no parity NoParity 1 odd parity OddParity 3 even parity EvenParity StopBitsCode: *0 1 stop bit OneStopBit 1 2 stop bits TwoStopBits WordLengthCode: 0 5 data bits WordLength5 1 6 data bits WordLength6 2 7 data bits WordLength7 *3 8 data bits WordLength8 * = Default Returns -4 : Port out of range. Expecting 0 to 3. -7 : Bad parity code selected. Expecting 0 to 2. -8 : Bad stop bits code. Expecting 0 or 1. -9 : Bad word length code. Expecting 0 to 3. Example /* set no parity, 1 stop bit, and 8 bit data for COM1 */ SioParms(COM1,NoParity,OneStopBit,WordLength8); See Also SioReset. PCL4C Reference Manual Page 25 SioPutc Function Transmit a character over a serial line. Syntax int SioPutc(Port,c) int Port; /* Port selected (COM1 thru COM4) */ char c; /* character to send */ Remarks The SioPutc function transmits one character over the selected serial line. If flow control has been enabled, then SioPutc may return a -1 (time out) if the number of tics specified in the SioFlow function was exceeded waiting for the modem to raise CTS. Refer to the User's Manual for a discussion of flow control. Returns -2 : Port not enabled. Call SioReset first. -4 : Port out of range. Expecting 0 to 3. -1 : Timed out waiting for CTS (flow control enabled) Example char crc; char buffer[128]; ... /* transmit 128 byte buffer + CRC */ crc = 0; for(i=0;i<128;i++) {crc = crcupdate( buffer[i], crc); SioPutc(Port, buffer[i]); } SioPutc(crc); See Also SioGetc and SioFlow. PCL4C Reference Manual Page 26 SioRead Function Reads any UART register. Syntax int SioRead(Port) int Port; /* Port selected (COM1 thru COM4) */ Remarks The SioReset function directly reads the contents of any of the 7 UART registers. This function is useful when debugging application programs, and as a method for verifying UART contents. Refer to the PCL Users Manual for a discussion of the 7 UART registers. Returns -3 : No buffer available. Call SioRxBuf first. -4 : Port out of range. Expecting 0 to 3. Example int Reg; /* UART register */ int Contents; /* contents of UART */ /* print contents of 7 UART registers */ for(Reg=0;Reg<7;Reg++) {Contents = SioRead(Port,Reg); printf("COM%d: UART Register %d = %d\n", 1+Port,Reg,Contents); } PCL4C Reference Manual Page 27 SioReset Function Initialize a serial port for processing. Syntax int SioReset(Port,BaudCode) int Port; /* Port selected (COM1 thru COM4) */ int BaudCode; /* baud code or -1 */ Remarks The SioReset function initializes the selected serial port. SioReset should be called after calling SioParm and SioRxBuf but before making any other calls to PCL4C. SioReset uses the parity, stop bits, and word length value previously set if SioParm was called, otherwise the default values (see SioParm) are used. Recall that COM1 and COM3 share the same interrupt vector and therefore cannot operate simultaneously. Similiarly, COM2 and COM4 cannot operate simultaneously. Any other combination of two ports can be used. By specifing NORESET (-1) for the baud rate code, the port will NOT be reset. This is used to "take over" a port from a host communications program that allows a "DOS gateway". External protocols can be implemented this way. See SioBaud for a list of the baud rate codes, or see "PCL4C.H". Returns -3 : No buffer available. Call SioRxBuf first. -4 : Port out of range. Expecting 0 to 3. -11 : Bad baud rate code selected. Expecting 0 to 9. -13 : UART undefined. SioUART(Port,0) was called previously. -14 : Bad or missing UART. You may not have hardware present. -15 : Port already enabled. SioReset has already been called. -16 : Cannot enable both COM1 & COM3 or COM2 & COM4. Example char Buffer[128]; int rc; ... SioRxBuf(COM1,Buffer,Size128); rc = SioReset(Com1,Baud38400); if(rc==0) puts("RESET ok"); else if(rc<0) SioError(rc); else {if(rc&OverrunError) puts("Overrun Error"); if(rc&ParityError) puts("Parity Error"); if(rc&FramingError) puts("Framing Error"); if(rc&BreakDetected) puts("Break Detected"); } See Also SioBaud, SioParms, SioRxBuf, SioDone, and SioUART. PCL4C Reference Manual Page 28 SioRI Function Reads the Ring Indicator (RI) modem status bit. Syntax int SioRI(Port) int Port; /* Port selected (COM1 thru COM4) */ Remarks The SioRI function is used to read the Ring Indicator (RI) modem status bit. Also see SioModem. Returns -2 : Port not enabled. Call SioReset first. -4 : Port out of range. Expecting 0 to 3. 0 : RI is clear. >0 : RI is set (RING has occurred). Example /* check for Ring */ if(SioRI(Port)) {puts("RING "); /* process RING */ ... } See Also SioDSR, SioCTS, SioDCD, and SioModem. PCL4C Reference Manual Page 29 SioRTS Function Sets, clears, or reads the Request to Send (RTS) line. Syntax int SioRTS(Port,Cmd) int Port; /* COM1 to COM4 */ char Cmd; /* RTS command (SET, CLEAR, or READ) */ Remarks The SioRTS function controls the Request to Send (RTS bit in the modem control register. The RTS line is used by some error correcting modems to implement hardware flow control. RTS is dropped by the computer to signal the modem not to send data, and is raised to signal the modem to continue. Refer to the User's Manual for a discussion of flow control. Commands (defined in PCL4C.H) are: SET ('S') -- set RTS (ON) CLEAR ('C') -- clear RTS (OFF) READ ('R') -- read RTS Returns -2 : Port not enabled. Call SioReset first. -4 : Port out of range. Expecting 0 to 3. -5 : Command is not one of 'S', 'C', or 'R'. 0 : RTS is OFF (READ Command). >0 : RTS is ON (READ Command). Example /* turn off RTS for modem */ SioRTS(Port,CLEAR); See Also SioFlow and SioDTR. PCL4C Reference Manual Page 30 SioRxBuf Function Sets up receive buffers. Syntax int SioRxBuf(Port,Buffer,SizeCode) int Port; /* Port selected (COM1 thru COM4) */ char *Buffer /* Receive buffer */ int SizeCode; /* Buffer size code */ Remarks The SioRxBuf function passes the address and size of the receive buffer to PCL4C. Recall that PCL4C requires a receive buffer for each port in simultaneous operation since the receive function is interrupt driven. SioRxBuf passes the receive buffer to PCL4C for both the primary (COM1/COM3) and secondary (COM2/COM4) ports. It must be called before any incoming characters can be received. SioRxBuf must be called before SioReset. Buffer size codes are listed in "PCL4C.H". Size Code Buffer Size PCL4C.H Name 0 8 bytes Size8 1 16 bytes Size16 2 32 bytes Size32 3 64 bytes Size64 4 128 bytes Size128 5 256 bytes Size256 6 512 bytes Size512 7 1024 bytes Size1024 or Size1K 8 2048 bytes Size2048 or Size2K 9 4096 bytes Size4096 or Size4K 10 8192 bytes Size8192 or Size8K 11 16384 bytes Size16384 or Size16K 12 32768 bytes Size32768 or Size32K Returns -4 : Port out of range. Expecting 0 to 3. -10 : Bad buffer size code. Expecting 0 to 11. Example char RxBuf[1024]; /* declare as global */ ... /* setup 1K receive buffer */ SioRxBuf(COM1, RxBuf, Size1024); /* ready to call SioReset */ See Also SioReset. PCL4C Reference Manual Page 31 SioRxFlush Function To flush the receive buffer associated with the specified port. Syntax int SioRxFlush(Port) int Port; /* Port selected (COM1 thru COM4) */ Remarks The SioRxFlush function will delete any characters in the receive buffer for the specified port. After execution, the receive buffer will be empty. Call SioRxBuf after resetting a port in order to delete any spurious characters. Returns -2 : Port not enabled. Call SioReset first. -4 : Port out of range. Expecting 0 to 3. Example char buffer[1024]; ... /* setup receive buffer & reset port */ SioRxBuf(COM1,buffer,Size1024); SioReset(COM1,Baud115200); /* flush any spurious character */ SioRxFlush(COM1); /* ready for serial processing ! */ ... See Also SioRxQue. PCL4C Reference Manual Page 32 SioRxQue Function Returns the number of characters in the receive queue. Syntax int SioRxQue(Port) int Port; /* Port selected (COM1 thru COM4) */ Remarks The SioRxQue function will return the number of characters in the receive queue. It can be used to implement XON/XOFF flow control. Returns -2 : Port not enabled. Call SioReset first. -4 : Port out of range. Expecting 0 to 3. Example #define XON 0x11 #define XOFF 0x13 int count; char last = XON; char Buffer[128]; ... SioRxBuf(COM1,Buffer,Size128); /* implement XON / XOFF */ count = SioRxQue(COM1); if((last==XON)&&(count>120)) {SioPutc(COM1,XOFF); last = XOFF; } if((last==XOFF)&&(count<8)) {SioPutc(COM1,XON); last = XON; } See Also SioRxFlush. PCL4C Reference Manual Page 33 SioTimer Function Returns the number of system clock tics since midnight. Syntax long SioTimer() Remarks The SioTimer function will return the number of system clock tics since midnight, at 18.2065 tics per second. This function is usefull for timing various functions. Also see SioDelay. Returns timer tics. Example long time; ... time = SioTimer(); ... printf("Elasped time = %ld tics\n",SioTimer() - time); See Also SioDelay. PCL4C Reference Manual Page 34 SioUART Function Sets the UART base address. Syntax int SioUART(Port,Address) int Port; /* COM1 to COM4 */ int Address; /* UART address */ Remarks The SioUART function sets the UART base address for the specified port. SioUART must be called before SioReset in order to have effect. Be extremely sure that you know what you are doing! Note that PCL4C uses the standard PC/XT/AT port addresses, interrupt request lines, and interrupt service vectors. Therefore, this function is only needed for non-standard ports. Returns >0 : The previous base address for this port. -4 : Port out of range. Expecting 0 to 3. Example /* Record the fact that you don't have COM4 */ SioUART(COM4, 0); See Also SioReset, SioIRQ. PCL4C Reference Manual Page 35 SioUnGetc Function "Un-gets" the last character read with SioGetc(). Syntax int SioUnGetc(Port,c) int Port; /* Port selected (COM1 thru COM4) */ char c; /* character to unget */ Remarks The SioUnGetc function returns ("pushes") the character back into the serial input buffer. The character pushed will be the next character returned by SioGetc. Only one character can be pushed back. This function works just like the "ungetc" function in the C language. Returns -2 : Port not enabled. Call SioReset first. -4 : Port out of range. Expecting 0 to 3. Example /* push back c so next SioGetc will get it */ SioUnGetc(Port,c); See Also SioReset. PCL4C Reference Manual Page 36 Function Sumary *********************************************************** * Function * Arg1 * Arg2 * Arg3 * Arg4 * *********************************************************** * SioBaud * Port * BaudCode * * * * SioBrkKey * * * * * * SioBrkSig * Port * Cmd * * * * SioCrtWrite * Ch * * * * * SioCTS * Port * * * * * SioDCD * Port * * * * * SioDelay * Tics * * * * * SioDone * Port * * * * * SioDSR * Port * * * * * SioDTR * Port * Cmd * * * * SioError * Code * * * * * SioFIFO * Port * FIFOcode * * * * SioFlow * Port * Tics * * * * SioGetc * Port * Tics * * * * SioKeyPress * * * * * * SioKeyRead * * * * * * SioInfo * Cmd * * * * * SioIRQ * Port * IRQcode * * * * SioLine * Port * * * * * SioLoopBack * Port * * * * * SioModem * Port * Mask * * * * SioParms * Port * Parity * StopBits *WordLength* * SioPutc * Port * Ch * * * * SioRead * Port * Register * * * * SioReset * Port * BaudCode * * * * SioRI * Port * * * * * SioRTS * Port * Cmd * * * * SioRxBuf * Port * Buffer * SizeCode * * * SioRxFlush * Port * * * * * SioRxQue * Port * * * * * SioTimer * * * * * * SioUART * Port * Address * * * * SioUnGetc * Port * Ch * * * *********************************************************** [ 33 functions ] PCL4C Reference Manual Page 37 Error Code Summary ***************************************************************** * Code * Description * ***************************************************************** * 0 * No error. * * -1 * Timeout waiting for I/O. * * -2 * Port not enabled. Call SioReset first. * * -3 * No buffer available. Call SioRxBuf first. * * -4 * Port out of range. Expected 0 to 3. (COM1 = 0) * * -5 * Expected 'S', 'C', or 'R' as 2nd argument. * * -6 * Expected 'A', 'C', or 'D' as 2nd argument. * * -7 * Bad parity code specified. Expected 0 to 7. * * -8 * Bad stop bits code specified. Expected 0 or 1. * * -9 * Bad wordlength code specified. Expected 0 to 3. * * -10 * Bad buffer size code specified. Expected 0 to 11. * * -11 * Bad baud rate code. Expected 0 to 9. * * -12 * Loopback test fails. * * -13 * UART undefined. * * -14 * Missing or bad UART. * * -15 * Port already enabled. * * -16 * Cannot enable both COM1 and COM3 or COM2 and COM4. * ***************************************************************** PCL4C Reference Manual Page 38