sh66k51a SinoWealth Micro-Electronics Corp. Ltd, sh66k51a Datasheet - Page 27

• Manufacturer Part Number: sh66k51a
• Description: 2k 4-bit Micro-controller With Lcd Driver
• Manufacturer: SinoWealth Micro-Electronics Corp. Ltd

11. Remote Control Carrier Synthesizer
The device has a built-in carrier synthesizer for infrared or RF remote control circuits.
System Register:
Setting CPS2 - 0, can program the carrier synthesizer in several different prescaler ratios.
The carrier-generating counter is an 8-bit count-up counter and two 8-bit data load registers (High level data register and
Low level data register). Writing data into the data load registers can initialize the counter.
After the system reset, the counter is automatically loaded with the contents of high level data register and output high level
at the same time. Then when the counter counts overflow from $FF to $00, the counter is automatically loaded with the
contents of low level data register and output low level at the same time. And when the counter counts overflow again from
$FF to $00, the counter will be loaded with the contents of high-level data register again. The above sequence makes a
complete loop. So the carrier synthesizer can output continuous carrier wave of certain duty and certain period.
If REMO is set to “1” from “0”, the carrier counter will be initialized to load high level data register and output high level,
whichever states the counter is.
Load register programming: User can modify low level data register to change the width of the low level or modify high level
data register to change the width of high level. In a way the carrier synthesizer can output carrier wave of different duties
and different period.
REM will remain outputting carrier wave in HALT mode, but will output GND in STOP mode.
Address
$0D
$13
CPS2
0
0
0
0
1
1
1
1
PULLEN
Bit3
-
CPS1
0
0
1
1
0
0
1
1
CPS2
Bit2
-
CPS0
CPS1
0
1
0
1
0
1
0
1
Bit1
-
REMO
CPS0
REM
Bit0
Prescaler Divide Ratio
System clock/2
System clock/2
System clock/2
System clock/2
System clock/2
System clock/2
System clock/2
System clock/2
R/W
R/W
W
R
27
Bit2 - 0: Carrier counter source pre-divider
Bit3: Port pull high enable control
Bit0: REMO output data
Bit0: REM pin output status
11
9
7
5
3
2
1
0
Remarks
Ratio N
2048
512
128
32
8
4
2
1
SH66K51A