R01UH0823EJ0100 Rev.1.00 Page 1309 of 1823
Jul 31, 2019
RX23W Group 37. Serial Sound Interface (SSI)
TSWNO Flag (Transmit System Word Number Flag)
This status flag indicates the current word number.
The initial value of this is 1, and its value is inverted when the data is transferred from the SSIFTDR register to the
transmit shift register.
This flag is initialized to 1 when the SSICR.TEN bit value is changed from 0 to 1.
When the data word length specified by the SSICR.DWL[2:0] bits is 18 bits or more, this flag indicates the system word
that is in the data transferred from the SSIFTDR register to the transmit shift register.
IIRQ Flag (Idle Interrupt Status Flag)
This status flag indicates whether this module is in idle state.
This flag is set regardless of the value of the SSICR.IIEN bit to allow polling.
The interrupt can be masked by setting the SSICR.IIEN bit to 0, but the interrupt cannot be cleared by writing 0 to this
flag.
If IIRQ flag = 1 and SSICR.IIEN bit = 1, an interrupt occurs.
ROIRQ Flag (Receive Overflow Interrupt Status Flag)
This status flag indicates that receive data was supplied at a higher rate than was required. If a receive overflow occurs,
stop reception and start from the beginning of the flowchart again.
This flag is set to 1 regardless of the setting of the SSICR.ROIEN bit. This flag can be set to 0 by writing 0 after
confirming it to be 1.
If ROIRQ flag = 1 and SSICR.ROIEN bit = 1, an interrupt occurs.
If ROIRQ flag = 1, the data was transferred from the transmit shift register to the SSIFRDR register while the receive
FIFO is full (SSIFSR.RDC[3:0] flags = 8h). This may lead to the loss of data.
Note: When an overflow occurs, the current data in the data buffer of this module is overwritten by the next incoming
data from the SSI interface.
RUIRQ Flag (Receive Underflow Interrupt Status Flag)
This status flag indicates that receive data was supplied at a lower rate than was required. If a receive underflow occurs,
stop reception and start the flowchart again from the beginning.
This flag is set to 1 regardless of the setting of the SSICR.RUIEN bit. This flag can be set to 0 by writing 0 after
confirming it to be 1.
If RUIRQ flag = 1 and SSICR.RUIEN bit = 1, an interrupt occurs.
If RUIRQ flag = 1, the SSIFRDR register was read while the receive FIFO is empty (SSIFSR.RDC[3:0] flags = 0h). This
may cause invalid receive data to be stored.
TOIRQ Flag (Transmit Overflow Interrupt Status Flag)
This status flag indicates that transmit data was supplied at a higher rate than was required. If a transmit overflow occurs,
stop transmission and start from the beginning of the flowchart again.
This flag is set to 1 regardless of the setting of the SSICR.TOIEN bit. This flag can be set to 0 by writing 0 after
confirming it to be 1.
If TOIRQ flag = 1 and SSICR.TOIEN bit = 1, an interrupt occurs.
If TOIRQ flag = 1, the SSIFTDR register had data written to it while the transmit FIFO is full (SSIFSR.TDC[3:0] flags =
8h). This may lead to the loss of data.
TUIRQ Flag (Transmit Underflow Interrupt Status Flag)
This status flag indicates that transmit data was supplied at a lower rate than was required. If a transmit underflow occurs,
stop transmission and start from the beginning of the flowchart again.
This flag is set to 1 regardless of the setting of the SSICR.TUIEN bit. This flag can be set to 0 by writing 0 after
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