
III PERIPHERAL BLOCK: SERIAL INTERFACE
B-III-8-20
EPSON
S1C33T01 FUNCTION PART
(3)
Receive errors
Three types of receive errors can be detected when receiving data in the asynchronous mode.
Since an interrupt can be generated by setting the interrupt controller, the error can be processed using an
interrupt processing routine. For details on receive error interrupts, refer to "Serial Interface Interrupts and
DMA".
Parity error
If EPRx is set to "1" (parity added), the parity is checked when data is received.
This parity check is performed when the data received in the shift register is transferred to the receive data
register in order to check conformity with PMDx settings (odd or even parity). If any nonconformity is found
in this check, a parity error is assumed and the parity error flag is set to "1".
Ch.0 parity error flag: PER0 (D3) / Serial I/F Ch.0 status register (0x401E2)
Ch.1 parity error flag: PER1 (D3) / Serial I/F Ch.1 status register (0x401E7)
Ch.2 parity error flag: PER2 (D3) / Serial I/F Ch.2 status register (0x401F2)
Ch.3 parity error flag: PER3 (D3) / Serial I/F Ch.3 status register (0x401F7)
Even when this error occurs, the received data in error is transferred to the receive data register and the receive
operation is continued. However, the content of the received data for which a parity error is flagged cannot be
guaranteed.
The PERx flag is reset to "0" by writing "0".
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 is set to "1".
Ch.0 framing-error flag: FER0 (D4) / Serial I/F Ch.0 status register (0x401E2)
Ch.1 framing-error flag: FER1 (D4) / Serial I/F Ch.1 status register (0x401E7)
Ch.2 framing-error flag: FER2 (D4) / Serial I/F Ch.2 status register (0x401F2)
Ch.3 framing-error flag: FER3 (D4) / Serial I/F Ch.3 status register (0x401F7)
Even when this error occurs, the received data in error is transferred to the receive data register 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 flag is reset to "0" by writing "0".
Overrun error
If during successive receive operations, a receive operation for the next data is completed before the receive
data register is read out, the receive data register is overwritten with the new data. Therefore, the receive data
register must always be read out before a receive operation for the next data is completed.
When the receive data register is overwritten, an overrun error is generated and the overrun-error flag is set to
"1".
Ch.0 overrun-error flag: OER0 (D2) / Serial I/F Ch.0 status register (0x401E2)
Ch.1 overrun-error flag: OER1 (D2) / Serial I/F Ch.1 status register (0x401E7)
Ch.2 overrun-error flag: OER2 (D2) / Serial I/F Ch.2 status register (0x401F2)
Ch.3 overrun-error flag: OER3 (D2) / Serial I/F Ch.3 status register (0x401F7)
Even when this error occurs, the received data in error is transferred to the receive data register and the receive
operation is continued.
The OERx flag 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 to disable receive
operations.