📄 fet140_uart01_19200.c
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//******************************************************************************
// MSP-FET430P140 Demo - USART0, UART 19200 Echo ISR, HF XTAL ACLK
//
// Description: Echo a received character, RX ISR used. Normal mode is LPM0,
// USART0 RX interrupt triggers TX Echo. Though not required, MCLK = LFXT1.
// ACLK = MCLK = UCLK0 = 3.58MHz
// Baud rate divider with 3.58Mhz XTAL @19200 = 3.58MHz/19200 = 186 (00BAh)
// //* An external 3.58Mhz XTAL on XIN XOUT is required for ACLK *//
//
//
// MSP430F149
// -----------------
// /|\| XIN|-
// | | | 3.58MHz
// --|RST XOUT|-
// | |
// | P3.4|------------>
// | | 19200 - 8N1
// | P3.5|<------------
//
//
// M. Buccini
// Texas Instruments Inc.
// Feb 2005
// Built with IAR Embedded Workbench Version: 3.21A
//******************************************************************************
#include <msp430x14x.h>
void main(void)
{
volatile unsigned int i;
WDTCTL = WDTPW + WDTHOLD; // Stop WDT
P3SEL |= 0x30; // P3.4,5 = USART0 TXD/RXD
BCSCTL1 |= XTS; // ACLK = LFXT1 = HF XTAL
do
{
IFG1 &= ~OFIFG; // Clear OSCFault flag
for (i = 0xFF; i > 0; i--); // Time for flag to set
}
while ((IFG1 & OFIFG)); // OSCFault flag still set?
BCSCTL2 |= SELM_3; // MCLK = LFXT1 (safe)
ME1 |= UTXE0 + URXE0; // Enable USART0 TXD/RXD
UCTL0 |= CHAR; // 8-bit character
UTCTL0 |= SSEL0; // UCLK = ACLK
UBR00 = 0xBA; // 3.58Mhz 19200 - 186
UBR10 = 0x00; //
UMCTL0 = 0x00; // no modulation
UCTL0 &= ~SWRST; // Initialize USART state machine
IE1 |= URXIE0; // Enable USART0 RX interrupt
_BIS_SR(LPM0_bits + GIE); // Enter LPM0 w/ interrupt
}
#pragma vector=UART0RX_VECTOR
__interrupt void usart0_rx (void)
{
while (!(IFG1 & UTXIFG0)); // USART0 TX buffer ready?
TXBUF0 = RXBUF0; // RXBUF0 to TXBUF0
}
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