13 UART (UART3)
13-8
Seiko Epson Corporation
S1C31D50/D51 TECHNICAL MANUAL
(Rev. 2.00)
USINn
V
DD
V
SS
USOUTn
RXD
VCC
GND
TXD
LEDA
S1C31 UART3
Infrared communication module
AMP
GND
VCC
Figure 13.5.4.1 Example of Connections with an Infrared Communication Module
The transmit data output from the UART3 Ch.
n
transmit shift register is output from the USOUT
n
pin after the low
pulse width is converted into 3/16 by the RZI modulator in SIR method.
Modulator input (shift register output)
Modulator output (USOUTn)
T
1
T
1
3
16
T
1
3
16
Figure 13.5.4.2 IrDA Transmission Signal Waveform
The received IrDA signal is input to the RZI demodulator and the low pulse width is converted into the normal
width before input to the receive shift register.
Demodulator input (USINn)
Demodulator output (shift register input)
T
2
Figure 13.5.4.3 IrDA Receive Signal Waveform
Notes: • Set the baud rate division ratio to 1/16 when using the IrDA interface function.
• The low pulse width (T
2
) of the IrDA signal input must be CLK_UART3_n
×
3 cycles or longer.
13.5.5 Carrier Modulation
The UART3 has a carrier modulation function.
Writing 1 to the UART3_
n
MOD.CAREN bit enables the carrier modulation function allowing carrier modulation
waveforms to be output according to the UART3_
n
MOD.PECAR bit setting. Data transmit control is identical to
that for normal interface even in this case.
Transmit data
CAREN = 0
CAREN = 1
PECAR = 0
CAREN = 1
PECAR = 1
CAREN = 0
CAREN = 1
PECAR = 0
CAREN = 1
PECAR = 1
Start
bit
1
1
1
0
0
1
0
0
Parity
bit
Stop
bit
USOUTn
(INVTX = 0)
USOUTn
(INVTX = 1)
Figure 13.5.5.1 Carrier Modulation Waveform
(UART3_nMOD.CHLN = 1, UART3_nMOD.STPB = 0, UART3_nMOD.PREN = 1)