
V PeRiPheRaL MoDuLes 3 (inteRFaCe): GeneRaL-PuRPose seRiaL inteRFaCe (eFsio)
V-1-24
ePson
s1C33L17 teChniCaL ManuaL
Framing error
If data with a stop bit = 0 is received, the serial interface assumes that the data is out of synchronization and
generates a framing error.
If two stop bits are used, only the first stop bit is checked.
When this error occurs, the framing-error flag FERx (D4/0x300Bx2) is set to 1.
FeRx: Serial I/F Ch.x Framing Error Flag in the Serial I/F Ch.x Status Register (D4/0x300Bx2)
Even when this error occurs, the received data in error is transferred to the receive data buffer and the receive
operation is continued. However, the content of the received data for which a framing error is flagged cannot be
guaranteed, even if no framing error is found in the following data received.
The FERx (D4/0x300Bx2) flag is reset to 0 by writing 0.
overrun error
Even when the receive data buffer is full (4 data have been received), the next (5th) data can be received into
the shift register. If there is no space in the buffer (data has not been read) when the 5th data has been received,
the 5th data in the shift register cannot be transferred to the buffer. If one more (6th) data is transferred to this
serial interface, the shift register (5th data) is overwritten with the 6th data and an overrun error is generated.
When an overrun error is generated, the overrun error flag OERx (D2/0x300Bx2) is set to 1.
oeRx: Serial I/F Ch.x Overrun Error Flag in the Serial I/F Ch.x Status Register (D2/0x300Bx2)
Even when this error occurs, the receive operation is continued.
OERx (D2/0x300Bx2) is reset to 0 by writing 0.
(4) terminating receive operation
When a data receive operation is completed, write 0 to the receive-enable bit RXENx (D6/0x300Bx3) to disable
receive operations. This operation clears (initializes) the receive data buffer (FIFO), therefore, make sure that
there is no data that has not been read in the receive data buffer before setting RXENx (D6/0x300Bx3) to 0.