UM10413
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© NXP B.V. 2011. All rights reserved.
User manual
Rev. 1 — 16 December 2011
164 of 268
NXP Semiconductors
UM10413
MPT612 User manual
18.3.6 SPI format with CPOL = 1, CPHA = 0
Single and continuous transmission signal sequences for SPI format with CPOL = 1,
CPHA = 0 are shown in
In this configuration, during idle periods:
•
CLK signal is forced HIGH
•
SSEL is forced HIGH
•
The transmit MOSI/MISO pad is in high impedance
If the SSP is enabled and there is valid data within the transmit FIFO, the start of
transmission is signified by the SSEL master signal being driven LOW which causes slave
data to be immediately transferred onto the MISO line of the master. Master’s pin MOSI is
enabled.
One half period later, valid master data is transferred to the MOSI line. Now that both the
master and slave data have been set, the SCK master clock pin goes LOW after one
further half SCK period. This means that data is captured on the falling edges and is
propagated on the rising edges of the SCK signal.
If a single word transmission, after all bits of the data word are transferred, the SSEL line
is returned to its idle HIGH state one SCK period after the last bit is captured.
a. Single transfer with CPOL = 1 and CPHA = 0
b. Continuous transfer with CPOL = 1 and CPHA = 0
Fig 47. SPI frame format with CPOL = 1 and CPHA = 0
MSB
LSB
LSB
Q
MSB
SCK
SSEL
MOSI
MISO
4 to 16 bits
aaa-000567
aaa-000610
MSB
LSB
LSB
Q
MSB
4 to 16 bits
MSB
LSB
LSB
Q
MSB
4 to 16 bits
SCK
SSEL
MOSI
MISO