Datasheet

Section 16 CIR Interface
Rev. 2.00 Sep. 28, 2009 Page 482 of 994
REJ09B0452-0200
16.4 Operation
The communication protocol of the NEC format is shown in figure 16.2. In the NEC format, data
consists of a header part, an address part, a command part, and a stop part. The TFM bits in CCR2
can select which data bytes to be stored in CIRRDR: four bytes of the address, address, command,
and command, or two bytes of the address and command. The carrier frequency is 38kHz.
Header Address
Address
Command
Command
Stop
CIRI
Figure 16.2 NEC Format
(1) Header, Address, and Command
When a 9-ms high level and the following 4.5-ms low level are detected, they are recognized as a
header. For addresses and commands, when both of a high-level period and the following low-
level period are 0.56 ms, they are recognized as logic 0. When a high-level period is 0.56 ms and
the following low-level period is 1.78 ms, they are recognized as logic 1.
Header Logic 1 Logic 0
A = 9.0 ms B = 4.5 ms
C = 0.56 ms
CC
CIRI
D = 1.78 ms
A: High-level period for a header
B: Low-level period for a header
C: High-level period for logic 0/1 and low-level period for logic 0
D: Low-level period for logic 1
[Legend]
Figure 16.3 Header, Address, and Command