I2C not working on STM8S103K3P6. what am I doing wrong?

[Rita Jonkute]

Posted on November 15, 2017 at 16:25The original post was too long to process during our migration. Please click on the attachment to read the original post.

[Pavel A.]

Posted on November 22, 2017 at 14:43

What exactly is not working? Do you have the same issue as in this thread ?

https://community.st.com/0D50X00009XkafxSAB

-- pa

[Rita Jonkute]

Posted on November 22, 2017 at 15:10

First, somehow DR (data register is not showing anything), I clean ADDR by reading SR1 and SR3, clean TXE by writing DR twice, but can't get any data to buffer from MXL90614 temperature sensor

[Pavel A.]

Posted on November 22, 2017 at 20:44

Well, the code *may be* correct - though it does not use the official STM library for i2c and system clock.

You need to hook a logic analyzer on i2c lines and see what the host sends and what the sensor answers.

-- pa

[Rita Jonkute]

Posted on November 22, 2017 at 20:48

Sure.

It send this. Though according to manual I send DR 2times to clear txe. Address of device 0x5A

.

[Pavel A.]

Posted on November 22, 2017 at 21:56

This is a write command because the lowest bit of the address byte (0xB4) is 0. To read, set the lowest bit to 1 (0xB5).

-- pa

[Rita Jonkute]

Posted on November 22, 2017 at 22:22

Shouldn't first I send something to slave - sensor, in order to read what data it should send to the stm8s103?

[Pavel A.]

Posted on November 24, 2017 at 14:57

The commands should be explained in the sensor's documentation.

-- pa