pc87317vul National Semiconductor Corporation, pc87317vul Datasheet - Page 185

• Manufacturer Part Number: pc87317vul
• Description: Pc87317vul/pc97317vul Superi/o Plug And Play Compatible With Acpi Compliant Controller/extender
• Manufacturer: National Semiconductor Corporation

Bits 4-0 - Demodulator Frequency (DFR(4-0))
Bits 7-5 - Demodulator Bandwidth (DBW(2-0))
0
7
These bits select the subcarrier’s center frequency for
the Consumer-IR receiver demodulator. Table 7-25
shows the selection for low speed demodulation (bit 5 of
RCCFG=0, see page 187), and Table 7-24 shows the
selection for high speed demodulation (bit 5 of RC-
CFG=1).
These bits set the demodulator bandwidth for the select-
ed frequency range. The subcarrier signal frequency
must fall within the specified frequency range in order to
be accepted. Used for both Sharp-IR and Consumer-IR
modes.
See Tables 7-23, 7-25 and bit 5 (RXHSC) of the Con-
sumer-IR Configuration (RCCFG) Register on page
187.
0
DBW2
6
x x x x x x
DFR Bits
DFR Bits
4 3 2 1 0
0 0 0 1 1
0 1 0 0 0
0 1 0 1 1
4 3 2 1 0
FIGURE 7-35. IRRXDC Register Bitmap
DBW1
1
5
TABLE 7-23. Consumer IR, High Speed Demodulator (RXHSC = 1) (Frequency Ranges in KHz)
DBW0
0
4
1
3
DFR4
min/max
min/max
0
2
DFR3
max
max
max
max
min
min
min
min
0
1
DFR2
TABLE 7-24. Sharp-IR Demodulator (Frequency Ranges in KHz)
1
0
DFR1
Reset
Required
Enhanced Serial Port with IR - UART2 (Logical Device 5)
DFR0
Demodulation Control
380.95
421.05
436.36
480.00
457.71
502.26
480.0
533.3
0 0 1
001
Register (IRRXDC)
Infrared Receiver
Offset 00h
DBW2-0 (Bits 7, 6 and 5 of IRRXDC)
DBW2-0 (Bits 7, 6 and 5 of IRRXDC)
363.63
444.44
417.39
505.26
436.36
533.33
0 1 0
457.1
564.7
Bank 7,
010
185
347.82
470.58
400.00
533.33
417.39
564.70
7.18.2 Infrared Transmitter Modulator Control
This register controls modulation subcarrier parameters for
Consumer-IR and Sharp-IR mode transmission. For Sharp-
IR, only the carrier pulse width is controlled by this register
- the carrier frequency is fixed at 500 KHz.
After reset, the value of this register is 69h, selecting a car-
rier frequency of 36 KHz and an IR pulse width of 7 sec for
Consumer-IR, or a pulse width of 0.8 sec for Sharp-IR.
Bits 4-0 - Modulation Subcarrier Frequency (MCFR)
These bits set the frequency for the Consumer-IR modula-
tion subcarrier. The encoding are defined in Table 7-26. Bits
7-5 - Modulation Subcarrier Pulse Width (MCPW)
436.4
600.0
0 1 1
011
0
7
Specify the pulse width of the subcarrier clock as shown
in Table 7-27.
1
6
FIGURE 7-36. IRTXMC Register Bitmap
Register (IRTXMC)
1
5
MCPW(2-0)
0
4
333.33
500.00
384.00
564.70
400.00
600.00
1 0 0
417.4
640.0
100
1
3
0
2
0
1
MCFR(4-0)
320.00
533.33
369.23
600.00
384.00
640.00
1
400.0
685.6
1 0 1
0
101
Reset
Required
Infrared Transmitter
Modulation Control
307.69
571.42
355.55
640.00
369.92
685.57
1 1 0
384.0
738.5
110
Offset 01h
www.national.com
(IRTXMC)
Register
Bank 7,