Other Parts Discussed in Thread: BQ76920, MSP430G2553
Hello,
The following schematic is my BQ76920 test circuit to sample 5 batteries' voltages. Now pins SDA and SCL are connected with a 10k pull-up to the VCC of the Launchpad and then connected with the SDA and SCL of the Lauchpad MSP430G2553 respectively. The program is downloaded from the official website of TI called sluc583.zip which I attach with this post.
After powering, turn on the switch S1 and then run the program in CCS 6.1.0. When debug it, I find that WriteStatus and ReadStatus are both zero.
WriteStatus = I2CSendBytes(I2CSlaveAddress, &TargetRegister, 1, &SentByte);
ReadStatus = I2CReadBytes(I2CSlaveAddress, ReadData, 2, &ReadDataCount);
I conclude that there is no problem on the instruction received from the microcontroller to BQ76920, but there is no data in the receive register UCB0RXBUF of the microcontroller . There is a prompt in the CCS "Error: cannot load from non-primitive location" which leads to no data received by the microcontroller , resulting in communication failure.
This problem has been annoying me for quit a long time and I don't know which step is wrong.
Best wishes,
Kevin.