231
Bit 6—Receive Data Register Full (RDRF): Bit 6 is a status flag indicating whether there is
receive data in RDR.
Bit 6: RDRF
Description
0
Indicates there is no receive data in RDR
(initial value)
[Clearing conditions]
•
After reading RDRF = 1, cleared by writing 0 to RDRF.
•
When data is read from RDR by an instruction.
1
Indicates that there is receive data in RDR
[Setting condition]
When receiving ends normally, with receive data transferred from RSR to
RDR
Note:
If a receive error is detected during data receiving, or if bit RE in serial control register 3
(SCR3) is cleared to 0, RDR and RDRF are unaffected and keep their previous states. An
overrun error (OER) occurs if receiving of data is completed while bit RDRF remains set
to 1. If this happens, receive data will be lost.
Bit 5—Overrun Error (OER): Bit 5 is a status flag indicating that an overrun error has occurred
during data receiving.
Bit 5: OER
Description
0
Indicates that data receiving is in progress or has been completed
*
1
(initial value)
[Clearing condition]
After reading OER = 1, cleared by writing 0 to OER
1
Indicates that an overrun error occurred in data receiving
*
2
[Setting condition]
When data receiving is completed while RDRF is set to 1
Notes: 1. When bit RE in serial control register 3 (SCR3) is cleared to 0, OER is unaffected and
keeps its previous state.
2. RDR keeps the data received prior to the overrun; data received after that is lost. While
OER is set to 1, data receiving cannot be continued. In synchronous mode, data
transmitting cannot be continued either.