Reading ASM330LHHX sensor using SPI

[AhpKim]

Hi, I'm trying to get sensor data using the SPI protocol, but it seems not to be working as it should be.

Developing environments are: S32 Design Studio for Power Architecture, MPC5748G, ASM330LHHX, dspi_driver example code

At first, I sent a read request for WHO_AM_I address 0x8F then the data sequence returned.

https://community.nxp.com/t5/S32K/S32K148-LPSPI-unexpected-data/m-p/1209756

then I followed the link above, but still, the same data sequence returned which was not what I wanted(0x6b).

So I changed the request address to 9A and some others, but still, the same data sequence returned.

The pictures above are who_am_i return data.

The data sequence is " 0x00 ... 0xD6 .... 0x00 ... 0x08 .... 0x00... 0x01 ... 0x00 ... 0xC0..."

What is the correct way to read and write sensor data? Is there a guide for this?

 

[PetrS]

Hi,

SPI protocol is given in device datasheet. Both the read register and write register commands are completed in 16 clock pulses or in multiples of 8 in case of multiple read/write bytes. 
So write/read at least 2 bytes with continuous PCS selection. 
If using non-blocking function you should test for end of transfer, for example by using DSPI_GetTransferStatus function, or use blocking transfer function; DSPI_MasterTransferBlocking

BR, Petr

[AhpKim]

Thanks for the reply,

I'm still a bit confused here.

I tried to write/read at 4 bytes with continuous PCS selection (Continous SS), but it didn't give any output. It says STATUS_BUSY. 

So this is how I configure the SPI component :

Now, I'm getting 6b occasionally, but the clock starts from 0(low).

========================================================================

So questions are these,

1. How should I configure it to have SPI timing mode 3 which makes the clock start from 1(high)? 

2. What's different between SPI_MasterTransfer and +Blocking except for timeout? 

Thanks, I'm really new to this so please bear with me.

[PetrS · Accepted solution]

Hi,

1) use "Active low" for clock polarity setting
2) both functions configure driver to start sending defined number of bytes, non-blocking function ends after this and you should test for end of transfer before it can be again called, for example by using DSPI_GetTransferStatus function.  Blocking transfer function does not finish until all defined number of bytes are sent or timeout expires.

BR, Petr