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R01UH0823EJ0100 Rev.1.00 Page 1386 of 1823

Jul 31, 2019

RX23W Group 38. Serial Peripheral Interface (RSPIa)

38.3.9 Initializing RSPI

If 0 is written to the SPCR.SPE bit or the RSPI sets the SPE bit to 0 because of the detection of a mode fault error, the

RSPI disables the RSPI function, and initializes some of the module functions. When a system reset is generated, the

RSPI initializes all of the module functions. The following describes initialization by the clearing of the SPCR.SPE bit

and initialization by a system reset.

38.3.9.1 Initialization by Clearing the SPE Bit

When the SPCR.SPE bit is set to 0, the RSPI performs the following initialization:

 Suspending any serial transfer that is being executed

 Stopping the driving of output signals (Hi-Z) in slave mode

 Initializing the internal state of the RSPI

 Initializing the transmit buffer of the RSPI (Set the SPTEF flag to 1)

Initialization by the clearing of the SPE bit does not initialize the control bits of the RSPI. For this reason, the RSPI can

be started in the same transfer mode as prior to the initialization if the SPE bit is set to 1 again.

The SPSR.SPRF, SPSR.OVRF, SPSR.MODF, and SPSR.PERF flags are not initialized, nor is the value of the RSPI

sequence status register (SPSSR) initialized. For this reason, even after the RSPI is initialized, data from the receive

buffer can be read in order to check the status of error occurrence during an RSPI transfer.

The transmit buffer is initialized to an empty state (the SPTEF flag is 1). Therefore, if the SPCR.SPTIE bit is set to 1

after RSPI initialization, a transmit buffer empty interrupt is generated. When the RSPI is initialized, in order to disable

any transmit buffer empty interrupt, 0 should be written to the SPTIE bit simultaneously with the writing of 0 to the SPE

bit.

38.3.9.2 System Reset

The initialization by a system reset completely initializes the RSPI through the initialization of all bits for controlling the

RSPI, initialization of the status bits, and initialization of data registers, in addition to the requirements described in

section 38.3.9.1, Initialization by Clearing the SPE Bit.

Renesas RX Series User Manual

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