CCS/TMS320F28377S: SPI and ADC problem

Szy Sob

Part Number: TMS320F28377S

Tool/software: Code Composer Studio

I used TMS320F28377S with extertnal ADC - AD7609 (www.analog.com/.../AD7609.pdf) . I communicate with ADC via SPI. ADC is 18 bit and I have a problem. How I can read 18 bits since the RXBUF registers are 16 ?

Thank you for help

Best regards

Szymon

over 7 years ago

0 Mark Labbato over 7 years ago

Guru 30330 points

Szymon,

Can you use two 9-bit words? Remember that if transmitting less than 16-bits per word, you need to left justify the data.

-Mark

0 Szy Sob over 7 years ago in reply to Mark Labbato

Intellectual 330 points

Thank you for answer, that's resolve my problem but i have one more question. What to do with the processor's MOSI line ? External AD7609 doesn't have MOSI line (it has only output pins)

Thank you for help

Best regards

Szyomn

0 Mark Labbato over 7 years ago in reply to Szy Sob

Guru 30330 points

You can choose to use that pin as an extra gpio or other peripheral function. The beauty of the gpio muxing is that you get to pick and choose what signals are made external. In this case, since the MOSI line is never used, you can choose to not bring it out. Ensure that the gpio mux for that pin is configured to the other desired function.

Regards,

Mark

0 Szy Sob over 7 years ago in reply to Mark Labbato

Intellectual 330 points

Hi
Thank you for help !!!

Best regards
Szymon

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CCS/TMS320F28377S: SPI and ADC problem