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器件型号：MSP-EXP430FR5739 您好！
我正在尝试使用以下代码与 EEPROM (M24C02-FMN6TP)通信。 如果我执行此代码并使用示波器观察 SDA 和 SCL、我只会看到一个"序列"：
开始条件- EEPROM 地址(0x50)-#WRITE_FLAG -来自 EEPROM 的 ACK - 1字节(0x66)-来自 EEPROM 的 ACK -停止条件
现在、问题不是为什么我只能看到一个序列、也不是我想知道为什么它只包含一个单字节。 问题是为什么序列中的那个字节是数据字节(0x66)而不是地址(0x05)？
感谢您的回复。
Christian
#include <msp430.h>
#include <stdint.h>
void init_16_MHz_clock(void)
{
//Unlock CS registers with CSKEY password.
CSCTL0 = CSKEY;
//Set DCOCLK = 16 MHz.
CSCTL1 &= ~(DCOFSEL1 + DCOFSEL0);
CSCTL1 |= DCORSEL + DCOFSEL_2;
//Set ACLK = SMCLK = MCLK = DCOCLK.
CSCTL2 = SELA_3 + SELS_3 + SELM_3;
//Set all dividers to 0.
CSCTL3 = DIVA_0 + DIVS_0 + DIVM_0;
//Lock CS registers again.
CSCTL0_H = 0;
}
void hold_watchdog_timer(void) {
WDTCTL = WDTPW + WDTHOLD;
}
void init_i2c(const uint8_t eeprom_address) {
P1SEL0 &= ~(0xC0u);
P1SEL1 |= 0xC0u;
UCB0CTLW0 |= UCSWRST;
UCB0CTLW0 &= ~(UCA10 + UCSLA10 + UCMM + UCTXACK + UCTXNACK + UCTXSTP +
UCTXSTT);
UCB0CTLW0 |= UCMST + UCMODE_3 + UCSYNC + UCSSEL__SMCLK + UCTR;
UCB0CTLW1 &= ~(UCETXINT + UCCLTO1 + UCCLTO0 + UCSTPNACK + UCSWACK + UCASTP1 +
UCASTP0 + UCGLIT1 + UCGLIT0);
UCB0CTLW1 |= UCASTP_2;
UCB0BRW = 160;
UCB0TBCNT = 1;
UCB0I2COA0 &= ~(UCGCEN + UCOAEN);
UCB0I2COA1 &= ~(UCOAEN);
UCB0I2COA2 &= ~(UCOAEN);
UCB0I2COA3 &= ~(UCOAEN);
UCB0ADDMASK |= 0x3FFu;
UCB0CTLW0 &= ~UCSWRST;
UCB0I2CSA = eeprom_address;
//Test if the bus is free, otherwise a manual clock on is generated.
if(UCB0STATW & UCBBUSY) {
P1SEL1 &= ~0x80;
P1OUT &= ~0x80;
P1DIR |= 0x80;
P1SEL1 |= 0x80;
}
UCB0IE = 0; UCB0IFG = 0; UCB0IV |= 0xFFFFu;
}
void eeprom_write(const uint8_t address, const uint8_t data) {
unsigned short i;
const uint8_t buffer[2] = {data, address};
UCB0CTLW0 |= UCTR;
UCB0IE |= UCTXIE0;
while(UCB0STATW & UCBBUSY);
UCB0CTLW0 |= UCTXSTT;
for(i = 2; i > 0; --i) {
UCB0TXBUF = buffer[i - 1];
while(!(UCB0IFG & UCTXIFG0));
}
UCB0IE &= ~UCTXIE0;
UCB0IFG = 0; UCB0IV |= 0xFFFFu;
while(UCB0STATW & UCTXSTP);
}
uint8_t eeprom_read(const uint16_t address) {
return 0;
}
int main(void) {
unsigned short i;
const uint8_t EEPROM_ADDRESS = 0x50u;
const uint8_t write_values[6] = {0x11u, 0x22u, 0x33u, 0x44u, 0x55u, 0x66u};
volatile uint8_t read_values[6] = {0};
hold_watchdog_timer();
init_16_MHz_clock();
init_i2c(EEPROM_ADDRESS);
//Write values to addresses 0x05..0x00 in the EEPROM.
for(i = 6; i > 0; --i) {
eeprom_write(0x00u + i - 1, write_values[i - 1]);
}
//Read values from addresses 0x05..0x00 in the EEPROM.
for(i = 6; i > 0; --i)
read_values[i - 1] = eeprom_read(0x00u + i - 1);
return 0;
}
