20 GENERAL-PURPOSE SERIAL INTERFACE (FSIO)
20-18
Seiko Epson Corporation
S1C33L26 TECHNICAL MANUAL
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 FER 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 OER/FSIO_STATUS
x
register is set to 1.
Even when this error occurs, the receive operation is continued.
OER 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 RXEN to disable receive opera-
tions. 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 RXEN to 0.
IrDA Interface
20.8
Outline of IrDA Interface
20.8.1
Each channel of the serial interface contains a RZI modulator circuit, allowing an infrared-ray communication cir-
cuit to be configured based on IrDA 1.0 simply by adding a simple external circuit.
RZI
Modulator
SOUT
x
LED
TXD
LED A
LED C
RXD
CX1
Vcc
CX2
GND
V
P1N
V
P1N
Photodiode
SIN
x
V
DD
V
SS
Serial I/F
RZI
Modulator
S1C33L26
Infrared communication module
8.1.1 Configuration Example of IrDA Interface
Figure 20.
This IrDA interface function can be used only when the selected transfer mode is an asynchronous mode.
Since the contents of the asynchronous mode are applied directly for the serial-interface functions other than the
IrDA interface unit, refer to Section 20.7, “Asynchronous Interface,” for details on how to set and control the data
formats and data transfers.