//******************************************************************************
// MSP430G2xx3 Demo - USCI_B0 I2C Slave RX single bytes from MSP430 Master
//
// Description: This demo connects two MSP430's via the I2C bus. The master
// transmits to the slave. This is the slave code. The interrupt driven
// data receiption is demonstrated using the USCI_B0 RX interrupt.
// ACLK = n/a, MCLK = SMCLK = default DCO = ~1.2MHz
//
// /|\ /|\
// MSP430G2xx3 10k 10k MSP430G2xx3
// slave | | master
// ----------------- | | -----------------
// -|XIN P1.7/UCB0SDA|<-|---+->|P1.7/UCB0SDA XIN|-
// | | | | |
// -|XOUT | | | XOUT|-
// | P1.6/UCB0SCL|<-+----->|P1.6/UCB0SCL |
// | | | |
// D. Dang
// Texas Instruments Inc.
// February 2011
// Built with CCS Version 4.2.0 and IAR Embedded Workbench Version: 5.10
//******************************************************************************
#include "msp430g2553.h"
volatile unsigned char RXData;
void main(void)
{
WDTCTL = WDTPW + WDTHOLD; // Stop WDT
P1SEL |= BIT6 + BIT7; // Assign I2C pins to USCI_B0
P1SEL2|= BIT6 + BIT7; // Assign I2C pins to USCI_B0
UCB0CTL1 |= UCSWRST; // Enable SW reset
UCB0CTL0 = UCMODE_3 + UCSYNC; // I2C Slave, synchronous mode
UCB0I2COA = 0x48; // Own Address is 048h
UCB0CTL1 &= ~UCSWRST; // Clear SW reset, resume operation
IE2 |= UCB0RXIE; // Enable RX interrupt
while (1)
{
__bis_SR_register(CPUOFF + GIE); // Enter LPM0 w/ interrupts
__no_operation(); // Set breakpoint >>here<< and read
} // RXData
}
// USCI_B0 Data ISR
#pragma vector = USCIAB0TX_VECTOR
__interrupt void USCIAB0TX_ISR(void)
{
RXData = UCB0RXBUF; // Get RX data
__bic_SR_register_on_exit(CPUOFF); // Exit LPM0
}
