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SSR0—Serial Status Register 0
Bit
7
TDRE
Initial value
1
Read/Write
R/(W)*
Transmit Data Register Empty
0
1
Note: * Can only be written with 0, to clear the flag.
578
6
5
RDRF
ORER
0
0
R/(W)*
R/(W)*
Error Signal Status
Data received normally—no error signal
[Clearing conditions]
0
• Upon reset, and in standby mode or module stop mode
• When 0 is written to ERS after reading ERS = 1
1
Error signal has been sent from receiving device, indicating parity error detection
[Setting condition]
When the low level of the error signal is sampled
Note: Clearing the TE bit in SCR to 0 does not affect the ERS flag, which retains its previous state.
Overrun Error
0
[Clearing condition]
When 0 is written to ORER after reading ORER = 1
1
[Setting condition]
When the next serial reception is completed while RDRF = 1
Receive Data Register Full
0
[Clearing conditions]
• When 0 is written to RDRF after reading RDRF = 1
• When the DMAC or DTC is activated by an RXI interrupt and reads data from RDR
1
[Setting condition]
When serial reception ends normally and receive data is transferred from RSR to RDR
[Clearing conditions]
• When 0 is written to TDRE after reading TDRE = 1
• When the DMAC or DTC is activated by a TXI interrupt and writes data to TDR
[Setting conditions]
• When the TE bit in SCR is 0
• When data is transferred from TDR to TSR and data can be written to TDR
H'FF7C
4
3
ERS
PER
0
0
R/(W)*
R/(W)*
Transmit End
0
Transmission is in progress
[Clearing conditions]
• When 0 is written to TDRE after reading TDRE = 1
• When the DMAC or DTC is activated by a TXI interrupt and writes data to TDR
1
Transmission has ended
[Setting conditions]
• Upon reset, and in standby mode or module stop mode
• When the TE bit in SCR is 0 and the ERS bit is also 0
• When TDRE = 1 ERS = 0 (normal transmission) 2.5 etu after transmission
of a 1-byte serial character when GM = 0 and BLK = 0
• When TDRE = 1 ERS = 0 (normal transmission) 1.5 etu after transmission
of a 1-byte serial character when GM = 0 and BLK = 1
• When TDRE = 1 ERS = 0 (normal transmission) 1.0 etu after transmission
of a 1-byte serial character when GM = 1 and BLK = 0
• When TDRE = 1 ERS = 0 (normal transmission) 1.0 etu after transmission
of a 1-byte serial character when GM = 1 and BLK = 1
Note: etu (Elementary Time Unit): Time for transfer of 1 bit
Parity Error
0
[Clearing condition]
When 0 is written to PER after reading PER = 1
1
[Setting condition]
When, in reception, the number of 1 bits in the receive data plus the parity bit
does not match the parity setting (even or odd) specified by the O/E bit in SMR
Smart Card Interface 0
2
1
TEND
MPB
1
0
R
R
Multiprocessor Bit Transfer
0
Data with a 0 multiprocessor bit
is transmitted
1
Data with a 1 multiprocessor bit
is transmitted
Multiprocessor Bit
0
[Clearing condition]
When data with a 0 multiprocessor bit is received
1
[Setting condition]
When data with a 1 multiprocessor bit is received
0
MPBT
0
R/W
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