Hardware Reference
In-Depth Information
Table 5-1.
IR Remote Waveform Times
Protocol
Brand
Component
High
Low
High
ms
2
NEC
Start bit
9
4.5
-
0 bit
0.56
0.56
-
1 bit
0.56
1.69
-
Stop bit
0.56
0.56
-
4
SIRCS
Start bit
2.4
0.6
-
0 bit
0.6
0.6
-
1 bit
1.2
0.6
-
5
RC5
Start bit
-
0.889
0.889
0 bit
-
0.889
0.889
1 bit
0.889
0.889
-
7
Japan
Start bit
3.38
1.69
-
0 bit
0.42
0.42
-
1 bit
0.42
1.69
-
8
Samsung
Start bit
4.5
4.5
-
0 bit
0.56
0.56
-
1 bit
0.56
1.69
-
Stop bit
0.56
0.56
-
The High/Low values shown in the table agree with the website. For our circuit, the
signals are
inverted
because of the way that the VS1838B brings the line
low
when a carrier
is detected. The logic sense of these signals are documented in Table
5-2
for clarity.
Table 5-2.
Carrier Signals as Seen by the Raspberry Pi GPIO
Level
GPIO
Meaning
High (1)
Low
Carrier present
Low (0)
High
Carrier absent
