SPI communication with SCL3300

[PatrickT]

Hey there!

I'm new in the development with the nrf9160dk. And I wanted to connect the Murata SCL3300 digital inclinometer to the development kit via the SPI lines. However, I seem to run into some problems, because I fail to get through the startup sequence described in the SCL3300's datasheet. I have tried for two weeks now, testing various libraries described and linked on the forum. I have confirmed that the sensor is working via a Laird Sentrius RM1xx LoRa & BLE module. 

The SCL3300 is physically connected as followed:

• CS: P0.13
• MISO: P0.12
• MOSI: P0.11
• SCK:  P0.10

The same settings were put in the overlay file. All the grounds are connected properly, the AVDD and DVIO from the chip are both powered by the boards 3v output. which might be a concern. Because the typical voltage ranges from 3v to 3.6v.

I manage to get an spi device and gpio device. With the gpio_pin_set function the chipselect pin goes to low and high when I need it to, this was checked with a multimeter. Whenever I use the spi_transceive function I recieve 0 as retval, which indicates a succesfull transmission. But it doesn't return any data at all. I do not have an oscilloscope on hand so I can't really test if the sck and MOSI MOSI timings are correct. I have attached the project and the datasheet from the SCL3300. 

Please let me know if I forgot to add something, or left some information out! 

Kind regards,

Patrick Torremans

spi_scl3300.zipDatasheet_SCL3300-D01 .pdf

[Kenneth]

Hello,

In situations like this my best approach is a logic analyzer trace, comparing working and failing. This will pretty quick show where the problem may be: e.g. missing or wrong signals, missing or wrong sequence of bytes, missing or wrong timing etc. Personally I use https://www.saleae.com/, but there are less costly solutions out there.

Best regards,
Kenneth

[PatrickT]

Thanks for the reply,

I have ordered this one: https://www.sparkfun.com/products/15033 It will arrive tomorrow. Did you perhaps have the time to look over the code? Maybe spot something I have missed.

Kind regards,

Patrick Torremans

[PatrickT]

This is the result, very strange because the sck doesnt function propperly. the CS goes to high too soon. the mosi and miso lines arent as expected as well.