UM10413
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© NXP B.V. 2011. All rights reserved.
User manual
Rev. 1 — 16 December 2011
151 of 268
NXP Semiconductors
UM10413
MPT612 User manual
17. SPI Interface SPI0
17.1 Features
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Single complete and independent SPI controller
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Compliant with Serial Peripheral Interface (SPI) specification
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Synchronous, serial, full duplex communication
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SPI master only
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Maximum data bit rate of one eighth of the input clock rate
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8 to 16 bits per transfer
17.2 Description
17.2.1 SPI overview
SPI is a full duplex serial interface. It can handle multiple slaves connected to a given bus.
Only a single master and a single slave can communicate on the interface during a given
data transfer. During a data transfer, the master always sends 8 to 16 bits of data to the
slave, and the slave always sends a byte of data to the master.
17.2.2 SPI data transfers
is a timing diagram that illustrates the four different data transfer formats that
are available with the SPI. This timing diagram illustrates a single 8-bit data transfer. The
timing diagram is divided into three horizontal parts. The first part describes the SCK and
SSEL signals. The second part describes the MOSI and MISO signals when the CPHA
variable is 0. The third part describes the MOSI and MISO signals when the CPHA
variable is 1.
In the first part of the timing diagram, note the following two points:
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the SPI is illustrated with CPOL set to both 0 and 1
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activation and de-activation of the SSEL signal: when CPHA = 1, the SSEL signal is
always inactive between data transfers; this is not guaranteed when CPHA = 0 (the
signal can remain active)
.