Hitachi H8/3032 Series Hardware Manual page 363

In receiving, the SCI operates as follows.
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After receiving, the SCI makes the following checks:
If these checks all pass, the RDRF flag is set to 1 and the received data is stored in RDR. If one of
the checks fails (receive error), the SCI operates as indicated in table 11-11.
Note: When a receive error occurs, further receiving is disabled. In receiving, the RDRF flag is
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Table 11-11 Receive Error Conditions
Receive Error
Overrun error
Framing error
Parity error
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The SCI monitors the receive data line. When it detects a start bit, the SCI synchronizes
internally and starts receiving.
Receive data is stored in RSR in order from LSB to MSB.
The parity bit and stop bit are received.
— Parity check: The number of 1s in the receive data must match the even or odd parity
setting of the O/E bit in SMR.
— Stop bit check: The stop bit value must be 1. If there are two stop bits, only the first stop
bit is checked.
— Status check: The RDRF flag must be 0 so that receive data can be transferred from
RSR into RDR.
not set to 1. Be sure to clear the error flags.
When the RDRF flag is set to 1, if the RIE bit is set to 1 in SCR, a receive-data-full interrupt
(RXI) is requested. If the ORER, PER, or FER flag is set to 1 and the RIE bit in SCR is also
set to 1, a receive-error interrupt (ERI) is requested.
Abbreviation
ORER
FER
PER
Condition
Receiving of next data ends
while RDRF flag is still set to
1 in SSR
Stop bit is 0
Parity of receive data differs
from even/odd parity setting
in SMR
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Data Transfer
Receive data not transferred
from RSR to RDR
Receive data transferred
from RSR to RDR
Receive data transferred
from RSR to RDR