The "twi_sensor" example is not working properly

[lisi]

SDK ： nRF5_SDK_15.0.0_a53641a

example： nRF5_SDK_15.0.0_a53641a\examples\peripheral\twi_sensor

I didn't change anything. After build and download to the Nordic development board,

The  LM75B_set_mode()  function in the main function is blocked and not executed normally. The blocking expression is while (m_xfer_done == false);

After I used the SDK： nRF5_SDK_15.2.0_9412b96 , also appeared the above situation

pics:

 

Please help to answer it, thanks.

[Jørgen Holmefjord]

Hi,

Did you connect a LM75B sensor to the TWI pins defined in the example, before running it?

If there is no sensor connected, the example will detect an error on the TWI bus and not set the m_xfer_done flag.

Best regards,
Jørgen

[Jørgen Holmefjord]

No, there is no sensor on the board. You need to connect it externally. This is written in the example documentation:

"This example assumes that an mbed application shield is used and that the SDA and the SCL lines are connected to Arduino define pins."

[lisi]

I was wrong，before this，I thought there was a temperature sensor on the pca10040 board .

But, when I was debugging other sensors, the analog I2C communication could be used.But the hardware I2C communicate could not be used , and also stopped on the expression (m_xfer_done == false)

[Jørgen Holmefjord]

There is a die temperature sensor inside the chip itself, but this does not use the TWI peripheral.

[lisi]

Thank you. I'll have a look

[Jørgen Holmefjord]

The TEMP peripheral does not give very accurate temperature readings. It is mainly used for temperature-dependent calibration tasks.

[lisi]

When I used the TWI peripheral  to debug my board that had temperature sensor.

First, I transplanted the nrf_drv_twi_tx function of the twi routine,modified the address of the sensor  and the address of the writable register, and configured the sdk_config.h of ble_app_uart routine according to the sdk_config.h of the twi_sensor routine. 

Then, I used the  oscilloscope to collect SCL clock line wareform, found there is no high and low level conversion.

[Jørgen Holmefjord]

I'm not sure I understand your comment. Do you not see any activity on the TWI bus? Are you sure that you are checking the correct pins? Are there any errors in the application?

[lisi]

Thank you very much for your answer. I have found the reason. It is the hardware, not the program.Thanks again for your earnest answer.