14 uaRT
S1C17153 TeChniCal Manual
Seiko epson Corporation
14-9
(Rev. 1.0)
irDa interface
14.8
This UART module includes an RZI modulator/demodulator circuit enabling implementation of IrDA 1.0-compatible
infrared communication function simply by adding basic external circuits.
The transmit data output from the UART transmit shift register is input to the modulator circuit and output from the
SOUT
x
pin after the Low pulse has been modulated to a 3
×
sclk16 cycle.
sclk16
Modulator input (shift register output)
Modulator output (SOUT
x
)
1 2 3
8 9 10 11
16
3
×
sclk16
Modulator input (shift register output)
Modulator output (SOUT
x
)
S1
D0
D1
D2
D3
D4
D5
D6
D7
P
S2
S3
(S1: Start bit, S2 & S3: Stop bits, P: Parity bit)
8.1 Transmission Signal Waveform
Figure 14.
The received IrDA signal is input to the demodulator circuit and the Low pulse width is converted to 16
×
sclk16
cycles before entry to the receive shift register. The demodulator circuit uses the pulse detection clock selected
separately from the transfer clock to detect Low pulses input (when minimum pulse width = 1.41 µs/115,200 bps).
(S1: Start bit, S2 & S3: Stop bits, P: Parity bit)
sclk16
Demodulator input (SIN
x
)
Demodulator output (shift register input)
1 2 3 4
16
16
×
sclk16
2
×
sclk16 or more
Demodulator input (SIN
x
)
Demodulator output (shift register input)
S1
D0
D1
D2
D3
D4
D5
D6
D7
P
S2
S3
8.2 Receive Signal Waveform
Figure 14.
irDa enable
To use the IrDA interface function, set IRMD/UART_EXP
x
register to 1. This enables the RZI modulator/de-
modulator circuit.
note
: This setting must be performed before setting other UART conditions.
Serial data transfer control
Data transfer control in IrDA mode is identical to that for normal interfaces. For detailed information on data
format settings and data transfer and interrupt control methods, refer to the preceding sections.
