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R01UH0823EJ0100 Rev.1.00 Page 1313 of 1823

Jul 31, 2019

RX23W Group 37. Serial Sound Interface (SSI)

Note: Since the SSIFRDR register is a 32-byte FIFO register, the maximum number of data bytes that can be read from

it while the RDF flag is 1 is indicated in the RDC[3:0] flags. If reading data from the SSIFRDR register is

continued after all the data is read, undefined values will be read.

RDC[3:0] Flags (Receive Data Indicate Flag)

These flags indicate the number of data bytes stored in the SSIFRDR register.

RDC[3:0] flags = 0h indicates no received data. RDC[3:0] flags = 8h indicates that 32 bytes of received data is stored in

the SSIFRDR register.

TDE Flag (Transmit Data Empty Flag)

This flag indicates that, when data is transferred from the SSIFTDR register to the transmit shift register, the number of

data bytes in the SSIFTDR register has become less than the transmit FIFO threshold value, and thus writing transmit

data to the SSIFTDR register has been enabled.

[Setting condition]

 The number of the transmit data bytes written to the SSIFTDR register is equal to or less than the value specified by

the SSIFCR.TTRG[1:0] bits.

[Clearing conditions]

 0 is written to the TDE flag after the TDE flag is confirmed to be 1.

 Transmit data is written to the SSIFTDR register using DMA or DTC transfer (transfer of the last block in block

transfer). Do not clear the TDE flag to 0 during DMA or DTC transfer.

Note: Since the SSIFTDR register is a 32-byte FIFO register, the maximum number of bytes that can be written to it

while the TDE flag is 1 is 8 – TDC[3:0]. If writing data to the SSIFTDR register is continued after all the data is

written, writing will be invalid and an overflow occurs.

TDC[3:0] Flags (Transmit Data Indicate Flag)

These flags indicate the number of data bytes stored in the SSIFTDR register.

TDC[3:0] flags = 0h indicates no data for transmission. TDC[3:0] flags = 8h indicates that 32 bytes of data for

transmission is stored in the SSIFTDR register.

Renesas RX Series User Manual

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