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about F28377s SPI data putout

winni.ye
Prodigy 60 points

Dear all:

          when i test F28377s spi model, I found at the same config , data output has two different condition:

         the first one : without data output, data channel is in hign level, data output is in low level

and the second : without data output , data channel is in low level, data output is in hign level

i want de second condition , how can i do that?

  • 0
    Prodigy 60 points
    i found the reason of that, a data's hignest bit is 1, when i translate the data , the level of data channel is to hign, what i want to ask is the data of SPITXBUF is unsigned or signed , what's means of left-justified
  • 0 in reply to winni.ye
    Guru 30330 points
    Hello,

    The data to be transmitted neither signed nor unsigned. The application must decide what format the data is in.

    Left justified means that if the data word is less than 16 bits, the data must be shifted to the left where the most significant bit of the data is placed into bit 15 of the transmit buffer. i.e If the word to be transmitted is 8-bits wide, the data must be placed into the upper 8 bits of the buffer.

    Can you elaborate on your original question.

    Thanks,
    Mark