Error Detection - Renesas RZ/A Series User Manual

RZ/A1L Group, RZ/A1LU Group, RZ/A1LC Group
16.4.6

Error Detection

In the normal serial transfer, the data written to the transmit buffer of the data register (SPDR) is serially transmitted, and
the serially received data can be read from the receive buffer of SPDR. If access is made to SPDR, depending on the
status of the transmit buffer/receive buffer or the status at the beginning or end of serial transfer, in some cases non-
normal transfers can be executed.
If a non-normal transfer operation occurs, this module detects the event as an overrun error or a mode fault error. Table
16.7 shows the relationship between non-normal transfer operations and the error detection function.
Table 16.7 Relationship between Non-Normal Transfer Operations and Error Detection Function
Occurrence Condition
A SPDR is written when the transmit buffer is full.
B Serial transfer is started in slave mode when transmit
data is still not loaded on the shift register.
C SPDR is read when the receive buffer is empty.
D Serial transfer terminates when the receive buffer is
full.
E The SSL input signal is negated during serial transfer
in slave mode.
On operation A shown in Table 16.7, this module does not detect an error. Whether SPDR can be written to or not can
be checked using the T[3:0] bits in the buffer data count setting register (SPBFDR).
Likewise, this module does not detect an error on operation B. In a serial transfer that was started before the shift register
was updated, this module sends the data that was received in the previous serial transfer, and does not treat the operation
indicated in B as an error. Note that the received data from the previous serial transfer is retained in the receive buffer of
SPDR, thus it can be correctly read.
Similarly, this module does not detect an error on operation C. To prevent extraneous data from being read, the number
of receive data units stored in the receive buffer should be read from the R[5:0] bits in the buffer data count setting
register (SPBFDR).
An overrun error shown in D is described in section 16.4.6 (1), Overrun Error. A mode fault error shown in E is
described in section 16.4.6 (2), Mode Fault Error.
R01UH0437EJ0600 Rev.6.00
Jan 29, 2021
16. Renesas Serial Peripheral Interface
Operation
Missing write data.
Data received in previous serial transfer
is serially transmitted.
The output data is undefined.
Missing serial receive data.
Serial transfer suspended.
Missing send/receive data.
Operation disabled.
Error Detection
None
None
None
Overrun error (only in slave
mode)
Mode fault error
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