cs5535 National Semiconductor Corporation, cs5535 Datasheet - Page 395

• Manufacturer Part Number: cs5535
• Description: Geode Cs5535 Companion Multi-function South Bridge
• Manufacturer: National Semiconductor Corporation

Revision 0.8
UART/IR Controller Register Descriptions
5.12.10.2 IR Transmitter Modulator Control Register (IRTXMC)
I/O Offset
Type
Reset Value
IRTXMC selects the modulation subcarrier parameters for CEIR and Sharp-IR mode transmission. For Sharp-IR, only the
subcarrier pulse width is controlled by this register; the subcarrier frequency is fixed at 500 kHz.
After reset, the value of this register is 69h, selecting a carrier frequency of 36 kHz and an IR pulse width of 7 µs for CEIR,
or a pulse width of 0.8 µs for Sharp-IR.
Bit
7:5
4:0
7
MCPW[2:0]
MCFR[4:0]
00000
00001
00010
00011
00100
00101
00110
00111
01000
01001
01010
01011
01100
0 0 0
0 0 1
0 1 0
0 1 1
1 0 0
1 0 1
1 1 0
1 1 1
Name
MCPW[2:0]
MCFR[4:0]
MCPW[2:0]
01h
R/W
69h
6
Low Frequency (TXHSC = 0) (CEIR only)
Description
Modulation Subcarrier Pulse Width. Specifies the pulse width of the subcarrier clock,
as shown in Table 5-49. (Default = 011.)
Modulation Subcarrier Frequency. These bits set the frequency for the CEIR modula-
tion subcarrier. The encoding is defined in Table 5-50. (Default = 01001.)
Table 5-50. CEIR Carrier Frequency Encoding
Table 5-49. Modulation Carrier Pulse Width
Low Frequency (TXHSC = 0)
5
IRTXMC Bit Descriptions
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
10.6
30 kHz
31 kHz
32 kHz
33 kHz
34 kHz
35 kHz
36 kHz
37 kHz
38 kHz
39 kHz
6.0 µs
7.0 µs
9.0 µs
IRTXMC Bit Map
µs
4
395
(Continued)
3
High Frequency (TXHSC = 1) (CEIR or Sharp-IR)
MCFR[4:0]
2
High Frequency (TXHSC = 1)
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
400 kHz
450 kHz
480 kHz
0.7 µs
0.8 µs
0.9 µs
1
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