TITLE:
How to Implement Infrared function with EM57000 series ?
REVISED DATE REVISED VERSION APPLY TO CHIPS APPLY TO SOFTWARE : : : : 13, JUNE, 1998 1.0 EM57000 Series Chip (Except EM57001,EM57400) ALL EM57000 series coding system above version 2.1
SEE ALSO: 1. EM57000 series contain infrared function ( EM57001 and EM57400 don't have infrared function ) which can generate 38K Hz square wave to ouside world from port 3.2 whenever it needs. 2. To activate infrared function, programmer should control bit 2, bit3 and bit4 of mode register : When bit4,3,2 of mode register is "101", infrared function will be activated. When bit4,3,2 of mode register is "000", infrared function will be disabled. MODE = 101?B => Enable infrared function. MODE = 000?B => Disable infrared function. Note that for bit 0 of mode register we mark it as ? means this bit can be "1" or "0". This bit have no relation with infrared function. bit 0 of MODE register can be used to enable/disable flash with volume. 3. User will need to enable port 3.2 by seting bit 2 of P3S as "0" so that 38K Hz square wave can send to outside world. But status of Port 3.2 can be "1" or "0" 4. Following is a simple example, it show you how to implement infrared function :
MOV MOV MOV MOV SIGN1: MOV MOV A, #0000B ; Enable port 3.2 P3S A A, #0100B ; Initial status of port 3.2 is "1" P3 A A #1010B ; Send out 38 K Hz square MODE A
RSTC DELAY1: CJC JMP SIGN2: MOV MOV DELAY2: CJC JMP SIGN2 DELAY1 ; P3.2 = 38K Hz ; for 8 mS
A #0000B ; Stop 38 K Hz square MODE A SIGN3 DELAY2 ; P3.2 = 1 ; for 8 mS
SIGN3: MOV A #1010B ; Send out 38 K Hz square again MOV MODE A RSTC DELAY3: CJC JMP SIGN4: ... SIGN4 DELAY3 ; P3.2 = 38K Hz ; for 8 mS
|
