The SFI register control block consists of the following five configuration registers:
The first four registers let the user define the following:
- Byte command for a serial flash read specified by the QSPI_SPI_SETUPi_REG[7:0] RCMD bit field
- Byte command for a serial flash write specified by the QSPI_SPI_SETUPi_REG[23:16] WCMD bit field
- Number of address bytes required for the particular type of serial flash specified by the QSPI_SPI_SETUPi_REG[9:8] NUM_A_BYTES bit field
- Number of “dummy bytes” that may be needed to support the fast read mode function of some serial flash devices. The QSPI_SPI_SETUPi_REG[11:10] NUM_D_BYTES bit field specifies the number of "dummy bits." In addition, the QSPI_SPI_SETUPi_REG[28:24] NUM_D_BITS bit field can also specify the number of "dummy bits."
- Whether the read command is single (normal), dual, or quad read mode command. This is specified by the QSPI_SPI_SETUPi_REG[13:12] READ_TYPE bit field. (i is equal to 0, 1, 2 and 3 and means that the QSPI_SPI_SETUPi_REG registers are associated with each of the four supported chip-selects [that is, four supported output SPI flash devices])
The QSPI_SPI_SWITCH_REG register acts as a static switch which allows the configuration port (shown in Figure 24-104) to connect directly to the SPI_CORE block, or allows the memory-mapped port (also shown in Figure 24-104) to connect to the SPI_CORE block. This is done using the QSPI_SPI_SWITCH_REG[0] MMPT_S bit.
In addition, the QSPI_SPI_SWITCH_REG[1] MM_INT_EN bit is used to enable or disable the word complete interrupt during operations using the memory-mapped port.