HD6432646 Hitachi, HD6432646 Datasheet - Page 504

• Manufacturer Part Number: HD6432646
• Description: (HD64F264x Series) 16-Bit Microcomputer
• Manufacturer: Hitachi

In serial reception, the SCI operates as described below.
[1] The SCI monitors the transmission line, and if a 0 start bit is detected, performs internal
[2] The received data is stored in RSR in LSB-to-MSB order.
[3] The parity bit and stop bit are received.
Note: * Subsequent receive operations cannot be performed when a receive error has occurred.
[4] If the RIE bit in SCR is set to 1 when the RDRF flag changes to 1, a receive data full interrupt
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synchronization and starts reception.
After receiving these bits, the SCI carries out the following checks.
[a] Parity check:
[b] Stop bit check:
[c] Status check:
If all the above checks are passed, the RDRF flag is set to 1, and the receive data is stored in
RDR.
If a receive error* is detected in the error check, the operation is as shown in table 13-11.
(RXI) request is generated.
Also, if the RIE bit in SCR is set to 1 when the ORER, PER, or FER flag changes to 1, a
receive error interrupt (ERI) request is generated.
The SCI checks whether the number of 1 bits in the receive data agrees with the parity
(even or odd) set in the O/E bit in SMR.
The SCI checks whether the stop bit is 1.
If there are two stop bits, only the first is checked.
The SCI checks whether the RDRF flag is 0, indicating that the receive data can be
transferred from RSR to RDR.
Also note that the RDRF flag is not set to 1 in reception, and so the error flags must be
cleared to 0.