Rev. 3.0, 03/01, page 149 of 390
(21) Infrared Configuration 2 Register (IIRC2R)
Address: H'10007106 (Bank 2, Read/ Write)
Bit
7
6
5
4
3
2
1
0
Bit Name
ACEN
-
-
-
CCTRL1 CCTRL0 DSIRI
DFIRI
Initial Value
0
-
-
-
0
0
0
0
R/W
R/W
-
-
-
R/W
R/W
R/W
R/W
Bit
Description
Default
7, 3, 2
4M pulse auto-chopping mechanism (ACEN, CCTRL1, CCTRL0)
These bits control the 4M pulse auto-chopping mechanism. This feature handles
transceivers which deliver single pulses that exceed the 165ns maximum supported by
the 4M demodulator. When autochop is enabled, the circuit measures a typical pulse
which during a frame preamble sequence and adjusts the chopping level accordingly. The
error threshold can be adjusted by using the chop control bits (CCTRL0 and CCTRL1).
The recommended setting for 4M mode is ACEN=1, CCTRL1=CCTRL0=0. These bits are
reset to 0 on power-up. If this feature is used, the software must set these bits accordingly
when entering 4M mode and reset them when leaving 4M mode. Chopping operation with
the autochop enable bit reset is provided for diagnostic tests of the transceiver and is not
recommended for normal operation where pulse widths can vary significantly.
The setting and their effects are:
Autochop Enable
/ CCTRL1 / CCTRL0 Effect
000
Chopping circuit is disabled
001
Extend the single pulse width tolerance to 187ns.
Back-to-back pulses must be greater than 209ns.
010
Extend the single pulse width tolerance to 229ns.
Back-to-back pulses must be greater than 249ns.
011
Extend the single pulse width tolerance to 208ns.
Back-to-back pulses must be greater than 229ns.
Autochop enabled with maximum tolerance for error.
Back-to-back pulses must be 62ns longer than a single pulse sample.
101
Autochop enabled with less tolerance for error. Back-to-back pulses
must be 42ns longer than a single pulse sample.
110
Autochop enabled with zero tolerance for error. Back-to-back pulsed
must be 42ns longer than a single pulse sample.
111
Autochop enabled with zero tolerance for error. Back-to-back pulses
must be longer than a single pulse sample. Digital transceiver with Rx
signal in synchronous with 48MHz clock.
-
6 - 4
Reserved
-
1
Disables SIR Interrupt (DSIRI)
Setting this bit to ‘1’ causes SIR interrupt request to be masked.
-
0
Disables FIR Interrupt (DFIRI)
Setting this bit to ‘1’ causes FIR interrupt request to be masked.
-
Summary of Contents for HD64465
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