20 GENERAL-PURPOSE SERIAL INTERFACE (FSIO)
20-24
Seiko Epson Corporation
S1C33L26 TECHNICAL MANUAL
10.2 Number of Receive Data
Table 20.
RXDNUM[1:0]
Number of data
0x3
4
0x2
3
0x1
2
0x0
1 or 0
(Default: 0x0)
When RXDNUM[1:0] is 0, it indicates that the receive data buffer contains 0 or 1 received data. When
RXDNUM[1:0] is 1 to 3, it indicates that the receive data buffer contains 2 to 4 received data.
D5
TEND: Transmit Status Flag Bit
Indicates the transmission status.
1 (R):
Busy (during transmitting)
0 (R):
End/idle (default)
TEND goes 1 after the first bit is shifted out from the shift register and goes 0 after the last bit is shifted
out. When data is transmitted successively in clock-synchronized master mode or asynchronous mode,
TEND maintains 1 until all data is shifted out (see Figure 20.6.3.1 and Figure 20.7.3.1). In clock-syn-
chronized slave mode, TEND goes 0 every time 1-byte data is shifted out (see Figure 20.6.3.2).
Note: TEND goes 0 at the falling edge of SCLK
x
to indicate that all the transmit data bits in the
transmit shift register are shifted out. Be aware that there is a half SCLK
x
cycle interval be-
tween setting TEND to 0 and latching the last bit by the receiver.
D4
FER: Framing Error Flag Bit
Indicates whether a framing error has occurred.
1 (R):
An error occurred
0 (R):
No error occurred (default)
1 (W):
Has no effect
0 (W):
Reset to 0
FER is an error flag indicating whether a framing error has occurred or not. When an error has oc-
curred, it is set to 1. A framing error occurs when data with a stop bit = 0 is received in asynchronous
mode.
FER is reset by writing 0.
D3
PER: Parity Error Flag Bit
Indicates whether a parity error has occurred.
1 (R):
An error occurred
0 (R):
No error occurred (default)
1 (W):
Has no effect
0 (W):
Reset to 0
PER is an error flag indicating whether a parity error has occurred or not. When an error has occurred,
it is set to 1. Parity checks are valid only in asynchronous mode with EPR set to 1 (parity added). This
check is performed when the received data is transferred from the shift register to the receive data buf-
fer.
PER is reset by writing 0.
D2
OER: Overrun Error Flag Bit
Indicates whether an overrun error has occurred.
1 (R):
An error occurred
0 (R):
No error occurred (default)
1 (W):
Has no effect
0 (W):
Reset to 0