OPT3101EVM: Error when I test i2c between external MCU and OPT3101EVM.

daniel Kim

Part Number: OPT3101EVM
Other Parts Discussed in Thread: OPT3101

Hi everyone

My question is about connection between external MCU and OPT3101EVM.
I'll use EFM32G MCU, want to test i2c with OPT3101EVM before embedded OPT3101 on my board.

So, I connected i2c pins of EFM32G MCU to J17(SCL_S, SDA_S) of OPT3101EVM.
There is no pull up registors on EFM32G MCU but I use internal pull up registors in EFM32G gpio peripheral.
The I2C pins of EFM32G MCU voltage is 3.3V.
When I test i2c with EFM32G MCU and OPT3101EVM, TI-Latte is not working and EFM32G can't be receive any data from OPT3101EVM.
I think that there is a problem because two i2c masters are on i2c bus.
How can I test i2c by EFM32G MCU?

Please help me..

over 7 years ago

0 Alex Bhandari-Young over 7 years ago

TI__Mastermind 25895 points

Hi Daniel,

I will get back on this early next week.

Best,

Alex

0 Alex Bhandari-Young over 7 years ago in reply to Alex Bhandari-Young

TI__Mastermind 25895 points

Hi Daniel,

I tested the OPT3101EVM with another MSP430 connected through the header i2c pins and it functioned properly. It is important to ensure that both MCUs are powered as otherwise the MCU that is powered off will pull the line low and that both boards share a common ground. The EVM should then function properly with Latte even through the other MCU is connected as long as the other MCU does not make any I2C transactions. Likewise the other MCU should be able to communicate with the OPT3101 on the EVM as long as Latte is not active and the MSP430 on the EVM is not performing any I2C reads or writes.

Best,

Alex

0 daniel Kim over 7 years ago in reply to Alex Bhandari-Young

Intellectual 320 points

Dear Alex

Thank you for your answer.

Best,

Daniel.

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OPT3101EVM: Error when I test i2c between external MCU and OPT3101EVM.