利用电位计替代旋转开关设计方案

x curve value since overflow

　　P2S2: ;read lower and upper thresholds using switch position value

　　MOV A, SWPOS ;multiply switch position value by 2

　　MOV B, #02H

　　MUL AB

　　MOV B, A ;save multiplied value as table offset

　　MOV DPTR, #HYSTBL;load base address of table pointer

　　MOVC A, @A+DPTR;look up table value from base address + offset

　　MOV LWRVAL, A;read lower threshold value

　　MOV A, B

　　INC DPTR ;increment base address

　　MOVC A, @A+DPTR

　　MOV UPRVAL, A;read upper threshold value

　　RET

　　HYSTBL:;TABLE OF LOWER & UPPER THRESHOLDS FOR SEVEN POSITION SWITCH

　　DB00D,41D;Switch state 0

　　DB34D,77D;Switch state 1

　　DB70D,113D;Switch state 2

　　DB106D,149D;Switch state 3

　　DB142D,185D;Switch state 4

　　DB178D,221D;Switch state 5

　　DB214D,255D;Switch state 6