Hello, Everyone, I use the UART sample code of MSP430F4270 recently
It use timer to make UART works, but I need to add UART setting
EX: N81 => Data bit : 8 bit , parity:None, stop bit : 1 bit
N82 => Data bit : 8 bit , parity:None, stop bit : 2 bit
#include <msp430.h>
#define RXD 0x02 // RXD on P1.1
#define TXD 0x01 // TXD on P1.0
// Conditions for 9600 Baud SW UART, SMCLK = 1048576
#define Bitime_5 0x47 // ~ 0.5 bit length + small adjustment
#define Bitime 0x6C // ~ 9620 baud
unsigned int RXTXData;
unsigned char BitCnt;
void TX_Byte (void);
void RX_Ready (void);
int main (void)
{
WDTCTL = WDTPW + WDTHOLD; // Stop watchdog timer
FLL_CTL0 |= XCAP14PF; // Configure load caps
CCTL0 = OUT; // TXD Idle as Mark
TACTL = TASSEL_2 + MC_2; // SMCLK, continuous mode
P1SEL = TXD + RXD; // P1.0/1 TA0 for TXD/RXD function
P1DIR = TXD; // TXD output on P1
// Mainloop
for (;;)
{
RX_Ready(); // UART ready to RX one Byte
__bis_SR_register(CPUOFF + GIE); // Enter LPM0 Until character RXed
TX_Byte(); // TX Back RXed Byte Received
}
}
// Function Transmits Character from RXTXData Buffer
void TX_Byte (void)
{
BitCnt = 0xA; // Load Bit counter, 8data + ST/SP
CCR0 = TAR; // Current state of TA counter
CCR0 += Bitime; // Some time till first bit
RXTXData |= 0x100; // Add mark stop bit to RXTXData
RXTXData = RXTXData << 1; // Add space start bit
CCTL0 = OUTMOD0 + CCIE; // TXD = mark = idle
while ( CCTL0 & CCIE ); // Wait for TX completion
}
// Function Readies UART to Receive Character into RXTXData Buffer
void RX_Ready (void)
{
BitCnt = 0x8; // Load Bit counter
CCTL0 = SCS + CCIS0 + OUTMOD0 + CM1 + CAP + CCIE; // Sync, Neg Edge, Capture
}
// Timer A0 interrupt service routine
#if defined(__TI_COMPILER_VERSION__) || defined(__IAR_SYSTEMS_ICC__)
#pragma vector=TIMERA0_VECTOR
__interrupt void Timer_A (void)
#elif defined(__GNUC__)
void __attribute__ ((interrupt(TIMERA0_VECTOR))) Timer_A (void)
#else
#error Compiler not supported!
#endif
{
CCR0 += Bitime; // Add Offset to CCR0
// RX
if (CCTL0 & CCIS0) // RX on CCI0B?
{
if( CCTL0 & CAP ) // Capture mode = start bit edge
{
CCTL0 &= ~ CAP; // Capture to compare mode
CCR0 += Bitime_5;
}
else
{
RXTXData = RXTXData >> 1;
if (CCTL0 & SCCI) // Get bit waiting in receive latch
RXTXData |= 0x80;
BitCnt --; // All bits RXed?
if ( BitCnt == 0)
//>>>>>>>>>> Decode of Received Byte Here <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
{
CCTL0 &= ~ CCIE; // All bits RXed, disable interrupt
__bic_SR_register_on_exit(CPUOFF); // Clear LPM0 bits from 0(SR)
}
//>>>>>>>>>> Decode of Received Byte Here <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
}
}
// TX
else
{
if ( BitCnt == 0)
CCTL0 &= ~ CCIE; // All bits TXed, disable interrupt
else
{
CCTL0 |= OUTMOD2; // TX Space
if (RXTXData & 0x01)
CCTL0 &= ~ OUTMOD2; // TX Mark
RXTXData = RXTXData >> 1;
BitCnt --;
}
}
}
Does anyone help me to figure out it ? Thanks。
