MSP430G2553: Way to disable repeated start detection in I2C

Nitish Agarwal91

Part Number: MSP430G2553

Hi,

Is there any way to disable the detection of repeated start without disabling the stop detection. Because when the repeated start condition is received the I2C stops listening for the stop condition if it doesn't receive its own address.

Thanks

Nitish

over 7 years ago

0 Johnson He over 7 years ago

TI__Mastermind 30406 points

Hi Nitish,

Can you tell me the purpose of disable the function of repeated start without disabling the stop detection? Is it used for other protocol? PMbus?

The following post may help you:

https://e2e.ti.com/support/microcontrollers/msp430/f/166/t/832191

Best Regards

Johnson

0 Nitish Agarwal91 over 7 years ago in reply to Johnson He

Intellectual 280 points

Hi Johnson,

Yes it is used for PMBUS. The PMBUS software library clearly states that it doesn't support group and extended command protocol. I am sure people must have faced the same situation and have found a workaround for this.

Thanks

Nitish

0 Johnson He over 7 years ago in reply to Nitish Agarwal91

TI__Mastermind 30406 points

Hi Nitish,

Sorry for the development of PMBus has some restrictions, the library we provide is only for your reference, you can consider modifying and developing on this basis to suit your system requirements.

Best Regards

Johnson

0 Nitish Agarwal91 over 6 years ago in reply to Johnson He

Intellectual 280 points

Hi,

So is there any way to implement the group command without using the library.

Thanks

Nitish

0 Johnson He over 6 years ago in reply to Nitish Agarwal91

TI__Mastermind 30406 points

Hi Nitish,

Currently we have no reference code for PMBus except the library.

Best Regards

Johnson

0 Nitish Agarwal91 over 6 years ago in reply to Johnson He

Intellectual 280 points

But is there a way where the block command can be executed in slave. Like it keeps looking for the stop command even though the address after the repeated start doesn't belong to the slave? The workaround was to have a general call come in and sends a stop but it violates the standard protocol.

0 Johnson He over 6 years ago in reply to Nitish Agarwal91

TI__Mastermind 30406 points

Hi Nitish，

I am sorry to come back to you so late, I am looking for a way to solve this problem. But the test results show that we don't have this function. The slave I2C hardware will filter the data and don't transmit to the UCB0RXBUF register if the address is not same as with salve after repeated start, so we don't support this function.

I suggest you can consider using the software I2C to implementation group command.

Best Regards

Johnson

0 Nitish Agarwal91 over 6 years ago in reply to Johnson He

Intellectual 280 points

Hi,

What is software I2C implementation ?

Thanks

Nitish

0 Johnson He over 6 years ago in reply to Nitish Agarwal91

TI__Mastermind 30406 points

Hi Nitish,

Software I2C that is use GPIO interface to simulate I2C protocol by output 1/0 or read input state. so that you can receive all the data of the I2C protocol, including the address, read/write bits, thus you can implement the group command you described.

Thanks.

Best Regards

Johnson

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MSP430G2553: Way to disable repeated start detection in I2C