OPT3101EVM: OPT3101EVM - External board i2c - EVM not send acknowledge

Ephraim Malka

Part Number: OPT3101EVM

Hello everyone :).

I'm trying connect the EVM to external MCU (nucleo Board), in addition, im trying to test I2C.

For somehow, the EVM didn't send an acknowledge.

i used oscilloscope in order to check if the right address is send, and it actually send the right address (0x58) but i don't receive acknowledge from the device.

here is a picture from oscilloscope:

I saw the example of i2c transaction in figure 27, i send only start bit without stop bit as write here:

Please, someone can help me and tell my why i don't receive from the device? what is wrong? ( btw to communication with MSP430 is working, but i want to communicate with external MCU nucleo)

thanks for help!

over 3 years ago

0 Brent Elliott over 3 years ago

TI__Expert 6800 points

Hi Ephraim,

Could you send a picture/diagram of the lines between the external MCU and the device? Are you configuring the I2C address the same way as the EVM? If not, the address may not be 0x58 as there are 3 address pins that are used to set the address.

Thank you,

Brent Elliott

0 Ephraim Malka over 3 years ago in reply to Brent Elliott

Prodigy 80 points

Hi Brent,
Thanks you for responding!

Of course, here is a block diagram:

How can I configure the address? and what is the default address if it is not configured?

0 Brent Elliott over 3 years ago in reply to Ephraim Malka

TI__Expert 6800 points

Hi Ephraim,

The default address is 1011 111. The address can be changed by pulling the pins A0, A1, and A2 to AVSS or AVDD. This will set the last 3 bits of the address.

Thank you,

Brent Elliott

Sensors

Sensors forum

OPT3101EVM: OPT3101EVM - External board i2c - EVM not send acknowledge