Below my code: int Read_ TMP102 (unsigned char TMPaddr) { // Protocol Base >>[START BIT][ADDR+R/W][REGISTER][DATA1][DATA2][STOP BIT] //I2C description document TI SLAU144J - page 461 ( www.ti.com/.../slau144j.pdf) while((UCB0STAT & BUSY)!= 0); // free bus while (UCB0CTL1 & UCTXSTP); // Ensure stop condition to sent // this part of code send the command to set the register that will be read. // command format = [start_bit][address + r/w][command to read][stop bit] i2c_tx(TMPaddr); // this function transmit the I2C address 0x48 ( TMP102 ) + register. i2c_stop(); // generate de stop bit. while((UCB0STAT & BUSY)!= 0); // verify if bus is free //start the read command UCB0CTL1 &= ~UCTR; // change I2C controller to receive mode, in this point address is loaded ( UCBxI2CCSA = slave address) UCB0CTL1 |= UCTXSTT; while((IFG2 & UCB0RXIFG )==0); // send start condiction to transceiver RX_INH = UCB0RXBUF; while((IFG2 & UCB0RXIFG )==0); // wait to receive a new byte. RX_INL = UCB0RXBUF; //GENERATE STOP BIT //while((UCB0STAT & BUSY)!= 0); // generate the stop condiction UCB0CTL1 |= UCTXSTP; while(UCB0CTL1 & UCTXSTP); Data_out = (int)RX_INH<<8; Data_out +=(int)RX_INL; __delay_cycles(10); return Data_out; } The strange behavior is that in first time that I sent the read command the MSP send one extra clock train and with it I receive that ACK of last TMP byte, after The MSP send only the correct number or train clock. the TMP102 is configured with 0x60A0 ( default). All ack perfect. After it i send command to set and read the sensor Sensor response the commands but now in I2C appear a new clock byte. FF ( that is wrong), but the data measured but sensor is right . After it I send a new command to read the temperature again but now dont have the last byte. I receive the last byte but now the NAK happen, and again the information is right. I verified the registes before and after the both trasmission and is everything same . Someone can help me solve this problem. Thanks
↧