[讨论] msp430f4152 LPM3模式下，9600bps 串口通信不能收发数据

18633013902 2016-6-22 10:55 楼主

RT,msp430f4152在LPM3模式下，时钟为SMCLK时，TimerA 模拟的UART串口不能通信，不知道什么原因造成的？ 本帖最后由 18633013902 于 2016-6-22 10:58 编辑

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沙发 clls2080000

时钟为ACLK时

点赞 2016-6-24 12:58

板凳 18633013902

引用: clls2080000 发表于 2016-6-24 12:58
时钟为ACLK时

什么意思？ACLK可以通信

点赞 2016-6-24 16:41

4楼 clls2080000

串口在ACLK时钟下 LPM3可以工作

点赞 2016-9-9 10:17

5楼 wojiaomt

你研究研究下面的官方例程吧，注意时钟设置：

//******************************************************************************
// MSP430x41x2 Demo - USCI_A0, 115200 UART Echo ISR, DCO SMCLK, LPM3
//
// Description: Echo a received character, RX ISR used. Normal mode is LPM3.
// Automatic clock activation for SMCLK through the USCI is demonstrated.
// USCI_A0 RX interrupt triggers TX Echo.
// Baud rate divider with 1048576hz = 1048576/115200 = ~9.1 (009h|01h)
// ACLK = LFXT1 = 32768Hz, MCLK = SMCLK = default DCO = 32 x ACLK = 1048576Hz
// //* An external watch crystal between XIN & XOUT is required for ACLK *//
//
// MSP430x41x2
// -----------------
// /|\| XIN|-
// | | | 32kHz
// --|RST XOUT|-
// | |
// | P6.6/UCA0TXD|------------>
// | | 115200 - 8N1
// | P6.5/UCA0RXD|<------------
//
//
// P. Thanigai
// Texas Instruments Inc.
// January 2009
// Built with CCE Version: 3.1 and IAR Embedded Workbench Version: 4.11
//******************************************************************************
#include <msp430x41x2.h>
void main(void)
{
volatile unsigned int i;
WDTCTL = WDTPW+WDTHOLD; // Stop WDT
FLL_CTL0 |= XCAP14PF; // Configure load caps
do
{
IFG1 &= ~OFIFG; // Clear OSCFault flag
for (i = 0x47FF; i > 0; i--); // Time for flag to set
}
while ((IFG1 & OFIFG)); // OSCFault flag still set?
P6SEL |= BIT5+BIT6; // P6.5,6 = USCI_A0 RXD/TXD
UCA0CTL1 |= UCSSEL_2; // SMCLK
UCA0BR0 = 0x09; // 1MHz 115200
UCA0BR1 = 0x00; // 1MHz 115200
UCA0MCTL = 0x02; // Modulation
UCA0CTL1 &= ~UCSWRST; // **Initialize USCI state machine**
IE2 |= UCA0RXIE; // Enable USCI_A0 RX interrupt
__bis_SR_register(LPM3_bits + GIE); // Enter LPM3, interrupts enabled
}
// Echo back RXed character, confirm TX buffer is ready first
#pragma vector=USCIAB0RX_VECTOR
__interrupt void USCI0RX_ISR(void)
{
while (!(IFG2&UCA0TXIFG)); // USCI_A0 TX buffer ready?
UCA0TXBUF = UCA0RXBUF; // TX -> RXed character
}