SPI S3C2440A RISC MICROPROCESSOR

22-4

SPI TRANSFER FORMAT The S3C2440A supports 4 different formats to transfer data. Figure 22-2 shows the four wavefor ms for SPICLK.
*
LSB of previously transmitted character
Cycle
MOSI
12345678
MSB 6 5 4 3 2 1 LSB
6 5 4 3 2 1 LSB
SPICLK
MISO MSB
CPOL = 1, CPHA = 1 (Format B)
*
MSB of character just received
Cycle
MOSI
12345678
MSB 6 5 4 3 2 1 LSB
6 5 4 3 2 1 LSB MSB
*
SPICLK
MISO MSB
CPOL = 1, CPHA = 0 (Format A)
Cycle
MOSI
12345678
6 5 4 3 2 1 LSB
6 5 4 3 2 1 LSB
*
SPICLK
MISO *LSB
CPOL = 0, CPHA = 1 (Format B)
*
MSB of character just received
Cycle
MOSI
12345678
MSB 6 5 4 3 2 1 LSB
6 5 4 3 2 1 LSB MSB
*
SPICLK
MISO MSB
CPOL = 0, CPHA = 0 (Format A)
*
LSB of previously transmitted character
*LSB
MSB
MSB
Figure 22-2 SPI Transfer Format