Product Specs

Table Of Contents
31 SPIM Serial peripheral interface master with
EasyDMA
Page
284
CSN
SCK
MOSI
0
1
2
n
ORC
ORC
MISO
A
B
C
m-2
m-1
m
ENDRX
ENDTX
CPU
1
2
START
Figure 71: SPI master transaction
31.4 Low power
When putting the system in low power and the peripheral is not needed, lowest possible power consumption
is achieved by stopping, and then disabling the peripheral.
The STOP task may not be always needed (the peripheral might already be stopped), but if it is sent,
software shall wait until the STOPPED event was received as a response before disabling the peripheral
through the ENABLE register.
31.5 Master mode pin configuration
The SCK, MOSI, and MISO signals associated with the SPI master are mapped to physical pins according to
the configuration specified in the PSEL.SCK, PSEL.MOSI, and PSEL.MISO registers respectively.
The PSEL.SCK, PSEL.MOSI, and PSEL.MISO registers and their configurations are only used as long as
the SPI master is enabled, and retained only as long as the device is in ON mode. PSEL.SCK, PSEL.MOSI
and PSEL.MISO must only be configured when the SPI master is disabled.
To secure correct behavior in the SPI, the pins used by the SPI must be configured in the GPIO peripheral
as described in Table 66: GPIO configuration on page 284 prior to enabling the SPI. This configuration
must be retained in the GPIO for the selected IOs as long as the SPI is enabled.
Only one peripheral can be assigned to drive a particular GPIO pin at a time. Failing to do so may result in
unpredictable behavior.
Table 66: GPIO configuration
SPI master signal
SPI master pin
Direction
Output value Comments
SCK
As specified in PSEL.SCK
Output
Same as CONFIG.CPOL
MOSI
As specified in PSEL.MOSI
Output
0
MISO
As specified in PSEL.MISO
Input
Not applicable