CHAPTER 10 SERIAL INTERFACE FUNCTION
User’s Manual U15195EJ5V0UD
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Figure 10-8. Asynchronous Serial Interface Reception Completion Interrupt Timing
Start
D0
D1
D2
D6
D7
RXD0 (input)
INTSR0 (output)
RXB0 register
Parity
Stop
Cautions 1. Be sure to read receive buffer register 0 (RXB0) even when a reception error occurs. If
the RXB0 register is not read, an overrun error will occur at the next data reception and
the reception error status will continue infinitely.
2. Reception is always performed assuming a stop bit length of 1.
A second stop bit is ignored.
(5) Reception error
The three types of errors that can occur during a receive operation are a parity error, framing error, and
overrun error. As a result of data reception, the various flags of the ASIS0 register are set (1), and a
reception error interrupt (INTSER0) or a reception completion interrupt (INTSR0) is generated at the same
time. The ISRM bit of the ASIM0 register specifies whether an INTSER0 or INTSR0 signal is generated.
The type of error that occurred during reception can be detected by reading the contents of the ASIS0
register during the INTSER0 or INTSR0 interrupt servicing.
The contents of the ASIS0 register are cleared (0) by reading the ASIS0 register.
Table 10-2. Reception Error Causes
Error Flag
Reception Error
Cause
PE
Parity error
The parity specification during transmission did not match
the parity of the reception data
FE
Framing error
No stop bit was detected
OVE
Overrun error
The reception of the next data was completed before data
was read from receive buffer register 0 (RXB0)
