程序 - 電表在不同供電模式下的安全過渡

IF XDATALEN <> 0 MOV DPTR,#XDATASTART MOV R7,#LOW (XDATALEN) IF (LOW (XDATALEN)) <> 0 MOV R6,#(HIGH (XDATALEN)) +1 ELSE MOV R6,#HIGH (XDATALEN) ENDIF CLR A XDATALOOP: MOVX @DPTR,A INC DPTR DJNZ R7,XDATALOOP DJNZ R6,XDATALOOP ENDIF IF PPAGEENABLE <> 0 MOV PPAGE_SFR,#PPAGE ENDIF IF PDATALEN <> 0 MOV R0,#LOW (PDATASTART) MOV R7,#LOW (PDATALEN) CLR A PDATALOOP: MOVX @R0,A INC R0 DJNZ R7,PDATALOOP ENDIF IF IBPSTACK <> 0 EXTRN DATA (?C_IBP) MOV ?C_IBP,#LOW IBPSTACKTOP ENDIF IF XBPSTACK <> 0 EXTRN DATA (?C_XBP) MOV ?C_XBP,#HIGH XBPSTACKTOP MOV ?C_XBP+1,#LOW XBPSTACKTOP ENDIF IF PBPSTACK <> 0 EXTRN DATA (?C_PBP) MOV ?C_PBP,#LOW PBPSTACKTOP ENDIF MOV SP,#?STACK-1 LJMP ?C_START ; Read a trim whose index is in A. Return the trim in A. CSEG AT 100H FUSE_TABLE: DB 0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff ; Trim test. Prefix "_?" tells Keil C it's reentrant. _?TRIM_TEST: PUSH IEN0 PUSH PSW ; Save registers, so it's reentrant. MOV PSW,00H ; Select registers before saving them PUSH DPL PUSH DPH PUSH ACC MOV A,R7 ; Save R7 from the current register set. PUSH ACC MOV A,R6 ; Save R6 from the current register set. PUSH ACC CLR IEN0.7 ; Wait for all fuses to be read once before checking fuses ; Complete fuse read takes 45 xtal clock cycles (1 fuse per xtal clock) MOV R7,#21 ; Wait 21x4 = 48 cycles loop_inner: DJNZ R7,loop_inner ; 4 cycles (in brownout, 1 cycle/clk) mov DPH, #HIGH(FUSE_TABLE) fuse_test_frst: ; check if values previously stored mov DPL,#LOW(FUSE_TABLE) clr a movc a,@a+dptr ; read fuse table xrl a,#55H jnz fuse_save MOV DPTR,#2003H ; Check if in brownout mode MOVX A,@DPTR JB ACC.6,PASS ; Mission mode, so don't check. fuse_test: mov r7,#8 ; byte counter fuse_test_lp1: mov DPTR,#FUSE_TABLE ; load pointer to fuse table mov a,r7 movc a,@a+dptr ; read fuse table mov r6,a mov a,r7 MOV DPTR,#20FDH ; TRIMSEL address MOVX @DPTR,A ; load reg to read trim MOV DPL,#0FFH ; TRIM value address MOVX A,@DPTR ; Get trim value cjne a,06H,FAIL ; test if flash read and trim == djnz r7,fuse_test_lp1 JMP PASS fuse_save: MOV DPTR,#2003H ; Check if in brownout mode MOVX A,@DPTR ; If brownout mode, don't save them and enter sleep. JNB ACC.6,FAIL ; mov 84H,#LOW(FUSE_TABLE) mov r7,#8 ; byte counter fuse_save_lp1: mov a,r7 MOV DPTR,#20FDH ; TRIMSEL address MOVX @DPTR,A ; load reg to read trim MOV DPL,#0FFH ; TRIM value address MOVX A,@DPTR ; Get trim value mov r6,a mov a,r7 mov dptr,#FUSE_TABLE add a,DPL mov DPL,a mov a,r6 orl 0B2H,#01H ; set to flash write movx @dptr,a ; write fuse table byte djnz r7,fuse_save_lp1 mov a,#55H ; control byte to mark mov dptr,#FUSE_TABLE orl 0B2H,#01H ; set to flash write movx @dptr,a ; write fuse table byte jmp PASS FAIL: MOV DPTR,#20A9H ; WAKE address MOV A,#0C1H ; SLEEP forces wake and fuse re-read MOVX @DPTR,A PASS: CLR A ; Select 0 MOV DPTR,#20FDH ; TRIMSEL address MOVX @DPTR,A ; clear trim select register. POP ACC MOV R6,A ; Restore R7 in this register set POP ACC MOV R7,A ; Restore R7 in this register set POP ACC POP DPH POP DPL POP PSW ; Restore registers, so it's reentrant. POP IEN0 RET END

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RTC例程

復(fù)位后，軟件不應(yīng)該馬上調(diào)節(jié)時鐘修正休眠模式下時差，而是首先計算需要消除的時間偏差，然會設(shè)置時鐘進行補償。