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TM4C1290NCPDT: The first dummy for Fast Read Quad I/O on QSSI

user6246923
Prodigy 140 points
Part Number: TM4C1290NCPDT


I'll try to use the QSSI function on TM4C1290CPDT as SPI communicatin to SPI Flash W25Q32JV made by Winbond.

W2532JV datasheet says that SPI master should set to Fxh as the first dummy data for Fast Read Quad I/O instruction

( refer to attached file ), however, I don't know a method about the setting of the first dummy data.

Please tell me what I should do for TM4C1290CPDT !

 

  • 0
    TI__Guru**** 191906 points

    Hi,

      The 'x' in the Fxh means it is don't care. Why don't you use 0xFF as the dummy data to write to the SPI flash. Of course, you can use any one of  0xF0, 0xF1...0xFE.0xFF as your choice. 

      

  • 0 in reply to Charles Tsai
    Prodigy 140 points

    Hi, Charles

    I might make you misunderstand.

    What I want to know is the procedure to let TM4C1290CPDT transfer Fxh (ex. 0xFF) to Flash memory as the dummy data.

    Is there a predetemined register for it ? 

    Do you know it ?

    regards,

    Hideyuki

  • 0 in reply to user6246923
    TI__Guru**** 191906 points

    Hi Hideyuki-san,

      There is no such thing as a predetermined register for a dummy write. Our MCU doesn't have such register. You will treat the dummy write as any writes. See below. 

      1. Write 8-bit with data 0xEB

      2. Write 8-bit address (A23-A16)

      3. Write 8-bit address (A15-A8)

      4 Write 8-bit address (A7-A0)

      5. Write 8-bit dummy data (0xFF)

      6. Change the MCU QSSI direction to read mode and ignore the the data on the bus

      7. Ignore the next dummy data on the bus

      8. Read the next byte 1

      9. Read the next byte 2

      10.........