• State TI Thinks Resolved
  • Locked Locked
  • Replies 1 reply
  • Answers 1 answer
  • Subscribers 30 subscribers
  • Views 342 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

PCM5242: The SPI read/writen bit is where?

John Handwork
Intellectual 420 points
Part Number: PCM5242

In the SPI Interface section of the PMC5242 data sheet (SLASE12A), the text states "The most significant bit is the read/write bit."  But the illustration below the text shows the R/Wn bit is bit 8 of 16: the LSbit of the control byte, clearly on the opposite side from the "MSB" hanging over the 16-bit value.

These seem to contradict each other.

Is the R/Wn the first bit or the 8th bit?  I don't know whether to believe what I read or believe what I see.

  • 0
    TI__Guru 53973 points

    Hi John,

    My understanding is that the device looks at the most significant bit for the R/W bit, not the LSB of the address.  I do not think I can confirm this in my lab for a few days, but in some other code I have written I used the MSB.  

    I believe the text is correct and the diagrams are wrong.  I will forward this to my systems team to see if we can update the datasheet in the future.

    Thanks,

    Paul