CHAPTER 19 IEBus CONTROLLER (V850/SB2)
User’s Manual U13850EJ4V0UM
481
Table 19-10. Communication Error Source Processing List (2/2)
Overrun Error
Underrun Error
Unit status
Reception
Transmission
Occurrence
condition
DR cannot be read in time before the next
data is received.
DR cannot be written in time before the next
data is transmitted.
Occurrence
condition
Location of
occurrence
Other than
data field
Data field
Other than
data field
Data field
Hardware
processing
−
• Reception stops.
• INTIE2 occurs.
• To start bit waiting status
Remarks 1.
Communication
between other units
does not end.
2.
Data cannot be
received until the
overrun status is
cleared.
−
• Transmission stops.
• INTIE2 occurs.
• To start bit waiting status
Broadcasting
communication
Software
processing
−
• DR is read and overrun status
is cleared.
• Error processing (such as
retransmission request)
−
• Error processing (such as
retransmission request)
Hardware
processing
−
• INTIE2 does not occur.
• NACK is returned.
• Data is retransmitted from
other unit.
Remark
Data cannot be
received
until
overrun
status is cleared.
−
• Transmission stops.
• INTIE2 occurs.
• To start bit waiting status
Individual
communication
Software
processing
−
• DR is read and overrun status
is cleared.
• Error processing (such as
retransmission request)
−
• Error processing (such as
retransmission request)
Parity Error
Unit status
Reception
Transmission
Occurrence
condition
Received data and received parity do not match.
−
Occurrence
condition
Location of
occurrence
Other than data field
Data field
Other than
data field
Data field
Hardware
processing
• Reception stops.
• INTIE2 occurs.
• To start bit waiting status
Remark
Communication between other units does not end.
−
−
Broadcasting
communication
Software
processing
• Error processing (such as retransmission)
−
−
Hardware
processing
• Reception stops.
• INTIE2 occurs.
• To start bit waiting status
• Reception does not stop.
• INTIE2 does not occur.
• NACK is returned.
• Data retransmitted by other
unit is received.
−
−
Individual
communication
Software
processing
• Error processing (such as
retransmission request)
−
−
−