Users Manual

Table Of Contents
R01UH0823EJ0110 Rev.1.10 Page 1322 of 1852
Nov 30, 2020
RX23W Group 37. Serial Sound Interface (SSI)
37.2.5 Transmit FIFO Data Register (SSIFTDR)
The SSIFTDR register is a write-only FIFO register consisting of eight stages of 32-bit registers for storing transmit data.
Write transmit data to the SSIFTDR register in 64-bit (two stages of FIFO) units regardless of the data word length
setting. If transmit data ends on a 32-bit boundary, write 00000000h for the other 32 bits, and stop transmission while 64-
bit writing is completed. When the transmit shift register is empty, the SSI transfers the transmit data written to the
SSIFTDR register to start serial transmission, which can be continued until the SSIFTDR register becomes empty.
Note that when the SSIFTDR register is full of data (32 bytes), the next data cannot be written to it. If writing is
attempted, it will be ignored and an overflow occurs.
37.2.6 Receive FIFO Data Register (SSIFRDR)
The SSIFRDR register is a read-only FIFO register consisting of eight stages of 32-bit registers for storing received data.
Each time 4 bytes of serial data is received, the SSI stores the received serial data in the SSIFRDR register from the
receive shift register according to the
PDTA bit setting. Receive operation can be continued until a maximum 32 bytes of
data have been stored to in the SSIFRDR register. The SSIFRDR register can be read but cannot be written to. Note that
when the SSIFRDR register is read when it stores no received data, undefined values will be read and a receive
underflow occurs.
After the SSIFRDR register becomes full of received data, the data received thereafter will be lost and a receive overflow
occurs.
Address(es): SSI0.SSIFTDR 0008 A518h
b31 b30 b29 b28 b27 b26 b25 b24 b23 b22 b21 b20 b19 b18 b17 b16
Value after reset:
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b15 b14 b13 b12 b11 b10 b9 b8 b7 b6 b5 b4 b3 b2 b1 b0
Value after reset:
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Address(es): SSI0.SSIFRDR 0008 A51Ch
b31 b30 b29 b28 b27 b26 b25 b24 b23 b22 b21 b20 b19 b18 b17 b16
Value after reset:
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b15 b14 b13 b12 b11 b10 b9 b8 b7 b6 b5 b4 b3 b2 b1 b0
Value after reset:
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