asm330lhhxg1 "who_am_i" register is reading back 0x48. Should be 0x6.

[arifkhan]

Connected STEVAL_$MKI243AA board to a nucleo-g491re board using 4 wire spi interface. The spi bus is setup to run @ 146 Kbits/sec. Reading back bad data. 

WHO_AM_I is 0x48

PIN_CTRL is 0x3E

Not sure but seem like the device is power

[TDK]

Why should it be 0x6?

[Federica Bossi]

Hi @arifkhan ,

The correct whoami, as reported also by @TDK , is 6Bh.

Probe with a logic analyzer and check:

• MOSI address byte
• MISO timing
• whether the returned byte is shifted by 1 bit
• whether CS stays stable

Did you try the reading also in I2C or SPI3?

[arifkhan]

hello Federica,

Yes, i have the scope connected to the 4 spi signals, I see 0x8F go out on the MOSI and I see 0x48 on the MISO wire every time.  I put a 10k pullup on the CS wire and also a 10K pulldown on the INT1 signal.

Yes I tried the I2C bus and I am able to read 0x6B data back from the WHOAMI register.

Rgds

[arifkhan]

hello Federica,

Is there some setup to this part at power up ?

I am completely at loss right now I would really appreciate some help from ST micro.

Rgds

[Andrew Neil]

Please show your scope trace.

Use the scope's screen capture if possible - it will give much better results than trying to photograph the screen!

Are you sure you have the correct SPI Mode?

Please post your schematic and show a minimum but complete code example which demonstrates the problem.

How to write your question to maximize your chances to find a solution

How to insert source code

[arifkhan]

ch1- csn,
ch2 = spi clk,
ch3 = mosi,
ch4 = miso.

SPI cycle read of WHOAMI register spiAddr = 0x8F, spiData = 0x48 (should be 0x6B).

spi mode 3 i.e. clk polarity high, clock 2nd edge.

[arifkhan]

Is there initialization code that must be run (write cycles) before the device will respond to reads?

I connect the STEVAL_$MKI243AA module into the steval-mki109D board and i can read the whoami register as 0x6B (i see it on the scope also). But if i connect the same  STEVAL_$MKI243AA to my nucleo-g491 eval board with jumpers (4 wire spi), the board is giving 0x48 for the WHOAMI register. 

what is the steval-mki109D board doing special to make it work?

Any help on this will be greatly appreciated.

[arifkhan]

I am really disappointed with the help i have received from ST micro. 

I should start looking for an alternate solution and and also transition away from using all STmicro parts in the future given there level of support.

[Andrew Neil]

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@arifkhan wrote:

I am really disappointed with the help i have received from ST micro. 

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You still haven't provided your schematic, or any code

How to write your question to maximize your chances to find a solution

Something is clearly very wrong with your MISO:

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@arifkhan wrote:

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Do you have a good ground connection?