Datasheet

Table Of Contents
Section 17 Serial Communications Interface 3 (SCI3, IrDA)
Rev. 2.00 Jul. 04, 2007 Page 402 of 692
REJ09B0309-0200
17.7.1 Transmission
During transmission, the output signals from the SCI (UART frames) are converted to IR frames
using the IrDA interface (see figure 17.20).
For serial data of level 0, a high-level pulse having a width of 3/16 of the bit rate (1-bit interval) is
output (initial setting). The high-level pulse can be selected using the IrCKS2 to IrCKS0 bits in
IrCR.
According to the standard, the high-level pulse width is defined to be 1.41 µs at minimum and
(3/16 + 2.5%) × bit rate or (3/16 × bit rate) + 1.08 µs at maximum. For example, when the
frequency of system clock φ is 10 MHz, being equal to or greater than 1.41 µs, the high-level
pulse width at minimum can be specified as 1.6 µs.
For serial data of level 1, no pulses are output.
UART frame
Data
IR frame
Data
0000 011 11 1
0000 011 11 1
Transmission
Reception
Bit
cycle
Pulse width is 1.6 µs to
3/16 bit cycle
Start
bit
Stop
bit
Stop
bit
Start
bit
Figure 17.20 IrDA Transmission and Reception