MSP432 I2C how to read 16Bit register

Michael Liesenberg85

Hi,

i need to write and read an EEPROM and its register size is 16Bit.

I am able to write it by doing this:

MAP_I2C_masterSendMultiByteStart(EUSCI_B3_BASE,ui16Reg>>8);

MAP_I2C_masterSendMultiByteNext(EUSCI_B3_BASE,(unsigned char)(ui16Reg&0xFF));
MAP_I2C_masterSendMultiByteFinish(EUSCI_B3_BASE,(unsigned char)(Data&0xFF));

I am tryng to do this but it is not working:

MAP_I2C_masterSendMultiByteStart(EUSCI_B3_BASE,(uint8_t)ui16Reg>>8);
MAP_I2C_masterSendMultiByteNext(EUSCI_B3_BASE,(uint8_t)(ui16Reg&0xFF)); <--------------------Gets stuck here

MAP_I2C_masterReceiveStart(EUSCI_B3_BASE);

How do i read 16Bit register using driverlib?

over 9 years ago

0 Clemens Ladisch over 9 years ago

Guru 321840 points

This looks like an 8-bit register with a 16-bit address.

Please clarify what you mean with "register size".

0 Michael Liesenberg85 over 9 years ago in reply to Clemens Ladisch

Mastermind 7560 points

Hi Clemens,

first i set the slave address using driverlib and then by saying "MAP_I2C_masterSendMultiByteStart(EUSCI_B3_BASE,ui16Reg>>8);" it will first send the slave address followed with the "ui16Reg>>8" value. Then i am trying to send the LSB register value to the slave but it is not working.
How can i write/read to a 16bit register using driverlib?

0 Clemens Ladisch over 9 years ago in reply to Michael Liesenberg85

Guru 321840 points

"Register value" means the value of the register, which in this case would be stored in the Data variable. I guess you meant "register number"?

Anyway, what do you mean with "not working"? What do you expect to happen, and what actually happens?

0 Michael Liesenberg85 over 9 years ago in reply to Clemens Ladisch

Mastermind 7560 points

Hi Clemens,

yes i meant register number.

So this is what i am trying to do:

Ho can i read/write to a 16Bit register with driverlib?

0 Clemens Ladisch over 9 years ago in reply to Michael Liesenberg85

Guru 321840 points

I don't see any obvious problem in your code.

Anyway, what do you mean with "not working"? What do you expect to happen, and what actually happens? And show your circuit.

0 Michael Liesenberg85 over 9 years ago in reply to Clemens Ladisch

Mastermind 7560 points

Hi Clemens,

so here is where it is hanging:

And here is the measured I2C and SDA wires:

The connections are correct and the slave is responding to its adress.

Here is my code:

0 Clemens Ladisch over 9 years ago in reply to Michael Liesenberg85

Guru 321840 points

The EUSCI module sends a stop condition after the first byte. Which is to be expected when you are configuring it to stop automatically after one byte.

You have to count all data bytes (sent and received) when using auto stop generation.
Alternatively, just don't use auto stop, and instead use I2C_masterReceiveMultiByteFinish() to receive the last byte.

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MSP432 I2C how to read 16Bit register