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器件型号：MSP430FR2433 主题中讨论的其他器件：TCA9535
当我运行以下程序时、它永远不会越过检查 I2C 总线是否繁忙的第一个 while 循环-这是为什么？
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//******************************************************************************
//
//! This example shows how to configure the I2C module as a master for
//! multi byte transmission in interrupt driven mode. The address of the slave
//! module is set in this example.
//!
//! Demo - EUSCI_B0 I2C Master TX multiple bytes to MSP430 Slave
//!
//! Description: This demo connects two MSP430's via the I2C bus. The master
//! transmits to the slave. This is the MASTER CODE. It cntinuously
//! transmits an array of data and demonstrates how to implement an I2C
//! master transmitter sending multiple bytes using the USCI_B0 TX interrupt.
//! ACLK = n/a, MCLK = SMCLK = BRCLK = default DCO = ~1MHz
//!
//! /|\ /|\
//! MSP430FR2xx_4xx Board 10k 10k MSP430FR2xx_4xx Board
//! slave | | master
//! ----------------- | | -----------------
//! | UCB0SDA|<-|----+->|UCB0SDA |
//! | | | | |
//! | | | | |
//! | UCB0SCL|<-+------>|UCB0SCL |
//! | | | |
//!
//! This example uses the following peripherals and I/O signals. You must
//! review these and change as needed for your own board:
//! - I2C peripheral
//! - GPIO Port peripheral (for I2C pins)
//! - SCL
//! - SDA
//!
//! This example uses the following interrupt handlers. To use this example
//! in your own application you must add these interrupt handlers to your
//! vector table.
//! - USCI_B0_VECTOR.
//
//******************************************************************************
#include "driverlib.h"
#include "Board.h"
//*****************************************************************************
//
//Set the address for slave module. This is a 7-bit address sent in the
//following format:
//[A6:A5:A4:A3:A2:A1:A0:RS]
//
//A zero in the "RS" position of the first byte means that the master
//transmits (sends) data to the selected slave, and a one in this position
//means that the master receives data from the slave.
//
//*****************************************************************************
#define SLAVE_ADDRESS 0x77
//*****************************************************************************
//
//Target frequency for SMCLK in kHz
//
//*****************************************************************************
#define CS_SMCLK_DESIRED_FREQUENCY_IN_KHZ 1000
//*****************************************************************************
//
//SMCLK/FLLRef Ratio
//
//*****************************************************************************
#define CS_SMCLK_FLLREF_RATIO 30
// Pointer to TX data
uint8_t TXData = 0;
uint8_t TXByteCtr;
void main(void)
{
WDT_A_hold(WDT_A_BASE);
//Set DCO FLL reference = REFO
CS_initClockSignal(
CS_FLLREF,
CS_REFOCLK_SELECT,
CS_CLOCK_DIVIDER_1
);
//Set Ratio and Desired MCLK Frequency and initialize DCO
CS_initFLLSettle(
CS_SMCLK_DESIRED_FREQUENCY_IN_KHZ,
CS_SMCLK_FLLREF_RATIO
);
//Set ACLK = VLO with frequency divider of 1
CS_initClockSignal(
CS_ACLK,
CS_VLOCLK_SELECT,
CS_CLOCK_DIVIDER_1
);
//Set SMCLK = DCO with frequency divider of 1
CS_initClockSignal(
CS_SMCLK,
CS_DCOCLKDIV_SELECT,
CS_CLOCK_DIVIDER_1
);
//Set MCLK = DCO with frequency divider of 1
CS_initClockSignal(
CS_MCLK,
CS_DCOCLKDIV_SELECT,
CS_CLOCK_DIVIDER_1
);
// Configure Pins for I2C
GPIO_setAsPeripheralModuleFunctionInputPin(
GPIO_PORT_UCB0SCL,
GPIO_PIN_UCB0SCL,
GPIO_FUNCTION_UCB0SCL
);
GPIO_setAsPeripheralModuleFunctionInputPin(
GPIO_PORT_UCB0SDA,
GPIO_PIN_UCB0SDA,
GPIO_FUNCTION_UCB0SDA
);
/*
* Disable the GPIO power-on default high-impedance mode to activate
* previously configured port settings
*/
PMM_unlockLPM5();
EUSCI_B_I2C_initMasterParam param = {0};
param.selectClockSource = EUSCI_B_I2C_CLOCKSOURCE_SMCLK;
param.i2cClk = CS_getSMCLK();
param.dataRate = EUSCI_B_I2C_SET_DATA_RATE_400KBPS;
param.byteCounterThreshold = 0;
param.autoSTOPGeneration = EUSCI_B_I2C_NO_AUTO_STOP;
EUSCI_B_I2C_initMaster(EUSCI_B0_BASE, ¶m);
//Specify slave address
EUSCI_B_I2C_setSlaveAddress(EUSCI_B0_BASE,
SLAVE_ADDRESS
);
//Set Master in receive mode
EUSCI_B_I2C_setMode(EUSCI_B0_BASE,
EUSCI_B_I2C_TRANSMIT_MODE
);
//Enable I2C Module to start operations
EUSCI_B_I2C_enable(EUSCI_B0_BASE);
EUSCI_B_I2C_clearInterrupt(EUSCI_B0_BASE,
EUSCI_B_I2C_TRANSMIT_INTERRUPT0 +
EUSCI_B_I2C_NAK_INTERRUPT
);
// Wait for I2C bus to be idle
while (EUSCI_B_I2C_isBusBusy(EUSCI_B0_BASE));
// Send the start condition
EUSCI_B_I2C_masterSendMultiByteStart(EUSCI_B0_BASE, 0x06);
// Wait for the start condition to be sent
while (!(EUSCI_B_I2C_getInterruptStatus(EUSCI_B0_BASE, EUSCI_B_I2C_START_INTERRUPT)));
// Clear the start condition flag
EUSCI_B_I2C_clearInterrupt(EUSCI_B0_BASE, EUSCI_B_I2C_START_INTERRUPT);
// send data byte
EUSCI_B_I2C_masterSendMultiByteNext(EUSCI_B0_BASE, 0x00);
while(1)
{
}
}
