Start-up

The normal bring up process:

• Establish the QSPI_REF_CLK (PMC clock controller)
• Release the reset
• Set the baud-rate divisor (QSPI divider)
• Configure the controller
• Enable interrupts
• Set PIO or DMA mode
• Enable the controller
• Issue controller command
• PIO operating mode
  • Read/write data via TX/RXFIFOs
  • Issue controller commands
  • Monitor FIFOs in interrupt handler
• DMA operating mode
  • Configure and launch the DMA transfer
    • Program DMA controller
    • Program interrupts
    • Send SPI command to flash device using controller commands sent to the command FIFO
    • Initiate DMA transfer
  • Wait for the DMA done interrupt [DONE] to be generated