465
CHAPTER 19 SERIAL INTERFACE CHANNEL 2
(e) Receive errors
Three kinds of errors can occur during a receive operation: a parity error, framing error, or overrun error.
When the data reception result error flag is set in the asynchronous serial interface status register (ASIS),
a receive error interrupt request (INTSER) is generated. INTSER is generated before receive completion
interrupt request (INTSR). Receive error causes are shown in Table 19-7.
What type of error was generated can be detected by reading the contents of ASIS in the reception error
interrupt servicing (INTSER). (see Figures 19-9 and 19-10).
The contents of ASIS are reset (0) by reading the receive buffer register (RXB) or receiving the next data
(if there is an error in the next data, the corresponding error flag is set).
Table 19-7. Receive Error Causes
Receive Errors
Cause
Parity error
Transmission-time parity specification and reception data parity do not match
Framing error
Stop bit not detected
Overrun error
Reception of next data is completed before data is read from receive register buffer
Figure 19-10. Receive Error Timing
Note
If a reception error is generated while bit 1 (ISRM) of asynchronous serial interface mode register
(ASIM) is set (1), INTSR will not be generated.
Cautions 1. The contents of the ASIS register are reset (0) by reading the receive buffer register
(RXB) or receiving the next data. To ascertain the error contents, ASIS must be read
before reading RXB.
2. The receive buffer register (RXB) must be read even if a receive error is generated.
If RXB is not read, an overrun error will be generated when the next data is received,
and the receive error state will continue indefinitely.
D1
D2
D6
D7
Parity
D0
RxD (Input)
STOP
START
INTSER (when framing/
overrun error occurs)
INTSER (when parity
error occurs)
INTSR
Note
Summary of Contents for PD78052
Page 2: ...2 MEMO ...
Page 8: ...8 MEMO ...
Page 16: ...16 MEMO ...
Page 36: ...36 MEMO ...
Page 158: ...158 MEMO ...
Page 174: ...174 MEMO ...
Page 240: ...240 MEMO ...
Page 260: ...260 MEMO ...
Page 340: ...340 MEMO ...
Page 392: ...392 MEMO ...
Page 438: ...438 MEMO ...
Page 482: ...482 CHAPTER 20 REAL TIME OUTPUT PORT MEMO ...
Page 510: ...510 MEMO ...
Page 524: ...524 MEMO ...
Page 560: ...560 MEMO ...
Page 576: ...576 MEMO ...
Page 598: ...598 MEMO ...
Page 602: ...602 MEMO ...