📄 fet140_i2c_09.c
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//******************************************************************************
// MSP-FET430P140 Demo - I2C, Master Reads from MSP430 Slave in Repeat Mode
//
// Description: This demo connects two MSP430's via the I2C bus. The master
// reads from the slave in repeat mode. This is the master code. The slave
// code is called fet140_i2c_10.c. The data from the slave TX
// begins at 0 and is incremented with each transfer. The received data is in
// RXData and is checked for validity. If the received data is incorrect, the
// CPU is trapped and the P1.0 LED will stay on. The RXRDYIFG interrupt is
// used to know when new data has been received.
// A Stop is issued after Master receives 6 bytes and then a new Start is
// issued.
// ACLK = n/a, MCLK = SMCLK = I2CCLOCK = DCO ~ 800kHz
// //* MSP430F169 Device Required *//
//
// /|\ /|\
// MSP430F169 10k 10k MSP430F169
// slave | | master
// -----------------| | | -----------------
// | P3.1|<-|---+->|P3.1 |
// | | | | P1.0|-->LED
// | | | | |
// | P3.3|<-+----->|P3.3 |
// | | | |
//
//
// H. Grewal/A. Dannenberg
// Texas Instruments Inc.
// Feb 2005
// Built with IAR Embedded Workbench Version: 3.21A
//******************************************************************************
#include <msp430x16x.h>
char RXData = 0;
unsigned int i = 0;
char TestData = 0;
void main (void)
{
WDTCTL = WDTPW + WDTHOLD; // Stop WDT
P3SEL |= 0x0A; // Select I2C pins
P1OUT = 0; // Clear P1.0
P1DIR |= 0x01; // P1.0 output
U0CTL |= I2C + SYNC; // Recommended init procedure
U0CTL &= ~I2CEN; // Recommended init procedure
I2CTCTL = I2CSSEL1 + I2CRM; // SMCLK, repeat Mode
I2CSA = 0x0048; // Slave Address is 048h
I2CIE = RXRDYIE; // Enable RXRDYIFG interrupt
U0CTL |= I2CEN; // Enable I2C
_EINT(); // Enable interrupts
U0CTL |= MST; // Master mode
I2CTCTL |= I2CSTT; // Initiate transfer
while (1)
{
if (i == 6)
{
i = 0;
TestData++;
I2CTCTL |= I2CSTP;
while (I2CTCTL & I2CSTP); // Check Stop Condition
U0CTL |= MST;
I2CTCTL |= I2CSTT;
}
i++;
_BIS_SR(CPUOFF); // Enter LPM0
P1OUT |= 0x01; // Set P1.0
if (TestData++ != RXData) break; // Test received data
P1OUT &= ~0x01; // Clear P1.0
}
while (1); // Trap CPU
}
// Common ISR for I2C Module
#pragma vector=USART0TX_VECTOR
__interrupt void I2C_ISR(void)
{
switch(I2CIV)
{
case 0: break; // No interrupt
case 2: break; // Arbitration lost
case 4: break; // No Acknowledge
case 6: break; // Own Address
case 8: break; // Register Access Ready
case 10: // Receive Ready
RXData = I2CDRB; // RX data
_BIC_SR_IRQ(CPUOFF); // Clear LPM0
break;
case 12: break; // Transmit Ready
case 14: break; // General Call
case 16: break; // Start Condition
}
}
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