// Chapter 14 6811 C programs// Jonathan W. Valvano// This software accompanies the book,// Embedded Microcomputer Systems: Real Time Interfacing// published by Brooks Cole, 1999 // Program 14.1. AART code to receive from an input-only full-duplex AART.// AART full duplex Input only, returns ID:S as 16-bitunsigned int GetAART(unsigned char addr){ // addr specifies which AART	unsigned char ID,S;     // inputs from AART	OutCh(addr|0x80);       // activate AART	ID=InCh();              // read ID	S=InCh();               // read status	return((ID<<8)+S);}     // return ID:S as 16-bit unsigned int//  Program 14.2. AART code to receive from an input-only half-duplex AART.// AART half duplex Input only, returns ID:S as 16-bitunsigned int GetAART(unsigned char addr){ // addr specifies which AART	unsigned char ID,S;     // inputs from AART	OutCh(addr|0x80);       // activate AART	InCh();                 // read echo of previous addr output	ID=InCh();              // read ID	S=InCh();               // read status	return((ID<<8)+S);}     // return ID:S as 16-bit unsigned int//  Program 14.3. AART code to transmit to an output-only half-duplex AART.// AART full duplex output onlyvoid PutAART(unsigned char addr,data){ // addr specifies which AART	OutCh(addr|0x80);       // activate AART	OutCh(data&0x7F);       // send data	OutCh(addr|0x80);}      // deactivate AART//  Program 14.4. AART code to transmit to an output-only half-duplex AART.// AART half duplex output onlyvoid PutAART(unsigned char addr,data){ // addr specifies which AART	OutCh(addr|0x80);       // activate AART	InCh();                 // read echo of addr output	OutCh(data&0x7F);       // send data	InCh();                 // read echo of data output	OutCh(addr|0x80);       // deactivate AART	InCh();}                // read echo of previous output//  Program 14.5. AART code to transmit then receive.// AART full duplex Output then Input, returns ID:S as 16-bitunsigned int PutGetAART(unsigned char addr,data){ // addr specifies which AART	unsigned char ID,S;     // inputs from AART	OutCh(addr|0x80);       // activate AART	OutCh(data&0x7F);       // send data	ID=InCh();              // read ID	S=InCh();               // read status	return((ID<<8)+S);}     // return ID:S as 16-bit unsigned int//  Program 14.6. 6811 code to output on the parallel network./* Port C output handshake tristate output example    */       #define STAF 0x80void main(void){   unsigned char Number;        DDRC = 0x00;      /* Port C are outputs, only when STRA=0 *//*  STAI=0  no interrupts,     HNDS=1, OIN=1 output handshake mode    CWOM=0  normal push/pull outputs on C     PLS=0   makes STRB a level output    EGA=1   means STRA active on the rise      INVB=0  makes STRB=0 after write CL */    PIOC = 0x1A;      Number=100; OutC(Number);  }void OutC(unsigned char data) {     PORTCL=data;       /* set PortC flip flops, and make STRB=0  *//* Port C data is driven only when STRA=0, otherwise Port C data=hiZ */    while ((PIOC & STAF) == 0);  }  /* wait for rise of STRA *///  Program 14.7. Bit fifo routines.//********************GetTxBit************************// returns TRUE=1 if successful, FALSE=0 if empty and data not removed// output is boolean 0 means FALSE, nonzero is trueint GetTxBit (unsigned int *datapt) {    if (SameBit(PutTxPt,GeTxtPt))       return(0);       /* Failed, fifo was empty */    else {        *datapt=(*GetTxPt.WPt)&GetTxPt.Mask;       GetTxPt.Mask=GetTxPt.Mask>>1;       if(GetTxPt.Mask==0) {         GetTxPt.Mask=0x8000;         ++GetTxPt.WPt;  // next word         if((GetTxPt.WPt)==&TxFifo[FifoSize]) GetTxPt.WPt=&TxFifo[0];} // wrap       return(1); }}