Serial Peripheral Interface (SPI)
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Fig 19-2 SPI Serial Format (SCPH = 0)
As data transmission starts on the falling edge of the slave select signal when SCPH = 0, whether the slave select signal of SPI master should
toggle or not before the next data frame during continuous data transfer can be configured through SS_T in CTRLR0 register. Ameba-D SPI
slave can communicate with serial-master no matter the slave select signal from master is toggling or not during continuous data transfer. The
timing diagram of SS toggling is illustrated in Fig 19-3. The timing diagram of SS not-toggling is illustrated in Fig 19-4.
Fig 19-3 SPI Serial Format Continuous Transfers (SCPH = 0 and SS toggling)
Fig 19-4 SPI Serial Format Continuous Transfers (SCPH = 0 and SS not-toggling)
When the configuration parameter SCPH = 1, both master and slave peripherals begin transmitting data on the first serial clock edge after the
slave select line is activated. The first data bit is captured on the second (trailing) serial clock edge. Data are propagated by the master and slave
peripherals on the leading edge of the serial clock. During continuous data frame transfers, the slave select line may be held active-low until the
last bit of the last frame has been captured. Fig 19-5 shows the timing diagram for the SPI format when the configuration parameter SCPH = 1.
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2019-05-15 10:08:03