Interrupt Response

;Knowledge point: Application of interruption; 1khz means inverting once every 500us

; t1 is mode 0, then m1m0=00h, use timer c/t=0 gate=0

; Mode 0 is a 13-bit timer, the total time is 2 to the 13th power of microseconds. = 8192 microseconds, minus 500 microseconds = 7692

;1111000001100 is converted to hexadecimal, the high 8 bits are equal to 0fh and the low 8 bits are 0ch

; Note: These two fields are not continuous. The lower 8 bits 01100 are filled with 0 before calculation.

;For beginners, please practice more to master the calculation method, and use an oscilloscope to check the frequency if possible

; The basic condition for interrupt response is that there is an interrupt request, the corresponding position of the interrupt enable register is 1, and the total interrupt open ea=1

;Once the response is interrupted, only the breakpoint is protected but not the scene, so the scene should be protected in general.

ORG 0000H;

LJMP MAIN;

ORG 001BH; jump to interrupt entry

LJMP INSER; to the interrupt service routine

ORG 030H;

MAIN: MOV TMOD,#00H;ti working mode 0

MOV TH1,#0F0H; load initial value

MOV TL1,#0CH;

SETB EA; Enable interrupt

SETB ET1; Timer t1 is enabled

LOOP: SETB TR1; start timer

HERE: SJMP HERE; Wait for interrupt, virtual main program, other programs can be inserted here

ORG 0200H; interrupt service routine starts from 200h

INSER: MOV TH1,#0F0H; reload the timing initial value

MOV TL1,#0CH;

CPL P3.3; reverse small speaker

RETI; interrupt return