SCT Scout SC4415, User Manual

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3.3.3 SPI Mode
When enabled, SPI mode enables the SC4415 to behave as an SPI Master device.
3.3.3.1 Summary
The SPI application mode is based on the common Serial Peripheral Interface used by many devices and products.
There are four signals required to communicate with a slave device using the SPI application mode, CLK, MOSI, MISO,
and SS.
The CLK Signal is the serial clock and is always driven by the master device. The MOSI and MISO signals are the
unidirectional data lines used to exchange data between the master and slaves. The direction of the MOSI and MISO
signals differ with respect to a master versus a slave device and can be determined by understanding the naming
convention. MOSI stands for Master-Out-Slave-In, which indicates that the signal is driven by the master and received
by the slave(s). MISO stands for Master-In-Slave-Out, which indicates that the signal is driven by a slave and received by
the master device.
SPI allows for multiple slave devices to share a single SPI interface. In order to do so, slave devices must be explicitly
enabled to become active on the bus. This is achieved by asserting the Slave Select (SSn) line connected to each
individual slave device. The SC4415 supports three individual Slave-Select lines, SS1-SS3.
The APIO pin functions for SPI mode are shown in Table 3.3.3.1-1. For more information about the APIO pins refer to
Section 2.5.1.
APIO1 APIO2 APIO3 APIO4 APIO5 APIO6 APIO7 APIO8
CLK MOSI MISO SS1 SS2 SS3
Table 3.3.3.1-1 – APIO Pin Mapping for SPI Mode
3.3.3.2 Details
The following features are available in this mode:

Standard SPI Read and Write operations

On-the-fly bus reconfiguration

Support for SPI Mode 0, 1, 2 and 3 (CPOL and CPHA)

Positive and negative Slave Select polarity

Configurable word widths for Command, Address, and Data

Configurable SCLK frequency from 50kHz up to 26MHz
The available commands specific to SPI Mode are listed in Table 3.3.3.2-1. Details about the command and its usage
can be found by referring to the relevant section for the command in Section 5.2.10.
Command Description Section
clock Set the SPI Clock rate 5.3.1
config Set the SPI interface full configuration 5.3.2
select Set the active Slave Select line 5.3.3
polarity Set the Slave Select line Polarity 5.3.4
protocol Set the SPI protocol mode 5.3.5
w_command Set the Command Width 5.3.6
w_address Set the Address Width 5.3.7
w_write Set the Write Data Width 5.3.8
w_read Set the Read Data Width 5.3.9
wait_read Set the number of wait cycles before the read data 5.3.10
s_write Perform an SPI Write operation 5.3.11
s_read Perform an SPI Read operation 5.3.12
Table 3.3.3.2-1 – SPI Command List