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/*
* rsbus.c
*
* Created on: 2014-4-26
* Author: Tuowen
*/
#include "rsbus.h"
#include "sysctl.h"
#define SYSRET (0xF0)
#define INSREP (0x0F)
// Maximum size of receive buffer
#define RSMAX (20)
#define CODE_LEN (6)
unsigned char rs_rxbuf[RSMAX];
unsigned char len;
unsigned char pch;
rshdlr rxhdlr;
enum rs_stat{REST,ST,ADDR,READ,DISCARD,ED,DED};
enum rs_stat rs_st=REST;
unsigned char rs_tx[CODE_LEN+RS_MAX]={STBIT1,0,RSADDR,MACTYPE};
volatile unsigned char tx_len;
volatile unsigned char tx_pos=255;
volatile unsigned char mac_stat[4]={0,0,0,0};
#pragma vector=USCIAB0TX_VECTOR
__interrupt void USCI0TX_ISR(void)
{
if (tx_pos == tx_len) // TX over?
{
UC0IE &= ~UCA0TXIE; // Disable USCI_A0 TX interrupt
RSOUT &= ~(RSPIN);
tx_pos = 255;
}
else
UCA0TXBUF = rs_tx[tx_pos++]; // TX next character
}
// Inline send for ISR
#pragma FUNC_ALWAYS_INLINE(rsbus_w_irq)
static __inline void rsbus_w_irq(unsigned char* buf,unsigned int len)
{
unsigned int i;
if (tx_pos < tx_len) // This shouldn't happen
return; // Race condition
RSOUT |= RSPIN;
tx_len=len+7;
unsigned int parity=MACTYPE^RSADDR;
rs_tx[1]=0; // Useless addr spec
for (i=0;i<len;++i)
parity^=(rs_tx[4+i]=buf[i]);
rs_tx[4+len]=parity;
rs_tx[5+len]=EDBIT0;
rs_tx[6+len]=EDBIT1;
tx_pos=0;
UCA0TXBUF=(STBIT0 & 0xff);
UC0IE |= UCA0TXIE;
}
#pragma vector=USCIAB0RX_VECTOR
__interrupt void rsbus_rx(void)
{
//IFG2&=(~UCA0RXIFG);
unsigned char dat;
dat=UCA0RXBUF;
/************ Simple State Machine *************/
switch (rs_st)
{
case REST:
rs_st=(dat==STBIT0)?ST:REST;
break;
case ST:
rs_st=(dat==STBIT1)?ADDR:REST;
break;
case ADDR:
if (dat==RSADDR)
{
rs_st=READ;
len=0;
pch=RSADDR;
}
else
rs_st=DISCARD;
break;
case READ:
rs_rxbuf[len++]=dat;
pch^=dat;
if (dat==EDBIT0)
rs_st=ED;
if (len>=RSMAX)
rs_st=REST;
break;
case DISCARD:
if (dat==EDBIT0)
rs_st=DED;
break;
case DED:
if (dat==EDBIT1)
rs_st=REST;
else
rs_st=DISCARD;
break;
case ED:
if (dat==EDBIT1)
{
rs_st=REST;
--len;
pch^=EDBIT0;
if (pch==0) // Parity check passed
{
if (len<2)
rsbus_w_irq((unsigned char*)mac_stat,4); // RETURN CURRENT STATUS
else
SYSCALL_IRQ(RSSYSBIT); // SYSCTL call happened here!!!
}
else // Parity check failed
{
dat = SYSRET ^ INSREP; // RETURN REP
rsbus_w_irq(&dat,1);
}
}
else
{
rs_rxbuf[len++]=dat;
pch^=dat;
rs_st=READ;
if (len>=RSMAX)
rs_st=REST;
}
break;
}
}
// Send something to the rs422 bus
// Length must not exceeds RS_MAX
void rsbus_w(int addr,unsigned char* buf,unsigned int len)
{
while (tx_pos < tx_len) // This shouldn't happen
__delay_cycles(100); // Race condition -> wait
unsigned int i;
if (len>RS_MAX)
return;
RSOUT |= RSPIN;
tx_len=len+7;
unsigned int parity=addr^MACTYPE^RSADDR;
rs_tx[1]=addr; // Useless addr spec
for (i=0;i<len;++i)
parity^=(rs_tx[4+i]=buf[i]);
rs_tx[4+len]=parity;
rs_tx[5+len]=EDBIT0;
rs_tx[6+len]=EDBIT1;
tx_pos=0;
UCA0TXBUF=(STBIT0 & 0xff);
UC0IE |= UCA0TXIE;
}
void rsbus_syscall()
{
rxhdlr(rs_rxbuf,len-1);
}
void rsbus_init(rshdlr hdlr) // If need to change this part consult user guide pg908
{
P1SEL |= BIT1 + BIT2 ; // P1.1 = RXD, P1.2=TXD
P1SEL2 |= BIT1 + BIT2 ; // P1.1 = RXD, P1.2=TXD
UCA0CTL1 |= UCSSEL_2; // UartCLK: SMCLK=4MHz
UCA0BR0 = 208; // BaudRate: 19200
UCA0BR1 = 0; // BaudRate: 19200
UCA0MCTL = UCBRS0 + UCBRS1; // Modulation UCBRSx = 3
UCA0CTL1 &= ~UCSWRST; // **Initialize USCI state machine**
IE2 |= UCA0RXIE; // Enable USCI_A0 RX interrupt
/******************* CTL for output buffer ***********************/
RSDIR |= RSPIN;
RSOUT &= ~(RSPIN); //HIGH for ENABLE -> Low as DEFAULT
/******************* SYSCTL INIT *************************/
rxhdlr=hdlr;
sysctl_reghdlr(RSSYSBIT,&rsbus_syscall);
}
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