SPRUI30H November 2015 – May 2024 DRA745 , DRA746 , DRA750 , DRA756
The SPI data shifter handles the capture and generation of the SPI interface signals. Based on control signals from the SPI_MACHINE and SPI_CNTIF blocks, data is shifted in or out on falling or rising edge of qspi1_sclk clock depending on the SPI clock mode selected. Table 24-281 lists the four defined clock modes of operation for the QSPI.
Mode | Settings in the QSPI_SPI_DC_REG Register | Description | |
---|---|---|---|
Value of the CKP bits | Value of the CKPH bits | ||
0 | 0 | 0 | Data input captured on falling edge of qspi1_sclk clock. Data output generated on falling edge of qspi1_sclk clock |
1 | 0 | 1 | Data input captured on rising edge of qspi1_sclk clock. Data output generated on rising edge of qspi1_sclk clock |
2 | 1 | 0 | Data input captured on rising edge of qspi1_sclk clock. Data output generated on rising edge of qspi1_sclk clock |
3 | 1 | 1 | Data input captured on falling edge of qspi1_sclk clock. Data output generated on falling edge of qspi1_sclk clock |
Mode 1 and Mode 2 are not supported and should not be used.
The CKPi and CKPHi (i = 0 to 3) bits of the QSPI_SPI_DC_REG register control the clock modes. Each of these 4 bits corresponds to an output chip select.
Figure 24-106 shows all four clock modes. In addition, through the DDi (i = 0 to 3) bits of the QSPI_SPI_DC_REG register the data can be delayed from one to three qspi1_sclk clock cycles after the corresponding qspi1_cs[n] (n = 0 to 3) goes active. The active state of each chip-select can also be controlled through the CSPi (i = 0 to 3) bits of the QSPI_SPI_DC_REG register.