Irda Interface - Epson S1C17001 Technical Manual

18.8 IrDA Interface

This UART module incorporates an RZI modulation/demodulation circuit enabling implementation of IrDA
1.0-compatible infrared communication simply by adding basic external circuits.
The transmission data output from the UART transmit shift register is input to the modulation circuit and output
from the SOUT pin after the Low pulse has been modulated to a 3/16 sclk cycle.
Modulation circuit input (shift register output)
Modulation circuit output (SOUT)
Modulation circuit input (shift register output)
Modulation circuit output (SOUT)
The received IrDA signal is input to the demodulation circuit and the Low pulse width is converted to 16 sclk cy-
cles before entry to the receive shift register. The demodulation circuit uses the pulse detection clock selected from
the prescaler output clock separately from the transfer cock to detect Low pulses input (when minimum pulse width
= 1.41 μs/115,200 bps).
Demodulation circuit input (SIN)
Demodulation circuit output
(shift register input)
Demodulation circuit input (SIN)
Demodulation circuit output
(shift register input)
IrDA enable
To use the IrDA interface function, set IRMD (D0/UART_EXP register) to 1. This enables the RZI modulation/
demodulation circuit.
∗ IRMD: IrDA Mode Select Bit in the UART Expansion (UART_EXP) Register (D0/0x4105)
Note: This must be set before setting other UART conditions.
S1C17001 TECHNICAL MANUAL
S1 D0
sclk
1 2 3
Figure 18.8.1: Transmission signal waveform
S1 D0 D1
sclk
1 2 3 4
irclk
At least 2 × irclk
Figure 18.8.2: Receive signal waveform
EPSON
(S1: Start bit, S2 & S3: Stop bits, P: Parity bit)
D1 D2 D3 D4 D5
8 9 10 11
3 × sclk
(S1: Start bit, S2 & S3: Stop bits, P: Parity bit)
D2 D3 D4 D5 D6
16 × sclk
18 UART
D6 D7 P S2 S3
16
D7 P S2 S3
16
221