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SPI Level Shifter

emaq

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I need to connect a 5V sensor to Raspberry Pi 3.3V SPI using a conventional level translator on all 4 SPI lines (MOSI, MISO, SCLK and ~CS) but it does not seem to work. The schematic of the level shifter is as under.

level_shifter.png


I have tested the same 5V sensor on Arduino Uno SPI and it works fine.

Are the 10k pull-up resistors a problem? If so what other options do I have?
 

KlausST

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Hi,

But the sensor expects 16 clocks and 16 bits of data while CS is low.
You still ignore the 16 bit transfer. Your transfer is 8 bit .. then CS gets HIGH. Please verify CS this with your scope.

BTW: please reduce picture file size: The TEK scopes usually are able to output screenshot pictures.
Or reduce the photo-picture filesize:
an example:

test.jpg

filesize is reduced from 3800 kBytes to 77 kBytes, but still no loss in (scope) information.
Mind: the forum is worldwide, and there are regions with slow internet.

Klaus
 

FvM

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SPI timing is correct for required mode 3. However, as stated before, ADIS16354 needs 16 bit SPI frames, respectively two 8 bit transfers during active CS period.
 

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