【導讀】FPGA完成各種時序邏輯控制、計數(shù)功能；單片機AT89C51. 和控制數(shù)碼管的顯示輸出。編程性相結(jié)合，采用十進制數(shù)字顯示，實現(xiàn)了測量信號的頻率、周期等基本功能。關(guān)鍵詞：等精度頻率計；可編程邏輯器件；VHDL；單片機AT89C51.

　　

【正文】 DEC R1 DJNZ R2, TFL1 MOV R0, LED5 MOV R1, 5FH MOV R3, 04H TFL2: MOV A, @R0 MOV @R1, A DEC R1 INC R0 DJNZ R3, TFL2 LCALL DIVD1 MOV 22H. 4DH MOV 21H, 4EH MOV 20H, 4FH JB , NEXT3 LCALL HEXBCD2 MOV LED8, OFH LCALL DISP NEXT3: RET 周期測試子程序 TESTT: LCALL TESTF MOV R0, 4FH MOV R1, 5FH MOV R2, 04H TETLI: MOV A, @R0 MOV @R1, A DEC R0 DEC R 1 DJNZ R2, TETL 1 MOV 48H, 00H MOV 49H, 00H MOV 4AH, 00H MOV 4BH, 00H MOV 4CH, 00H MOV 4DH, OFH MOV 4EH, 42H MOV 4FH, 40H LCALL DIVDI MOV 22H, 4DH MOV 21 H, 4EH MOV 20H, 4FH LCALL HEXBCD2 MOV LED8,們 OH LCALL DISP RET 。頻率周期測試計數(shù)子程序 FTJS: SETB CHOICE SETB CLRTRIG CLR CLRTRIG SETB START LCALL T 1 S LCALL T1 S LCALL T1 S LCALL T1 S LCALL TIS LCALL TI S LCALL T I S LCALL T1 S CLR START FLO: JB EEND, FL0。 MOV R0, LED1 MOV R3, 08H。 FL1: MOV A, P0 MOV @R0, A INC R0 MOV A, P2 INC A。 MOV P2, A DJNZ R3, FL 1 MOV P2, 00H RET TIS: MOV INT Rl, OFFH TSM3: MOV INT R0, OFFH TSM4: DJNZ INTee R0, TSM4 DJNZ INTes RI, TSM3 RET 。測脈寬子程序 TESPW: MOV R4, 02H LCALL PWZJS MOV R0, 3FH。+ MOV R l, 4FH MOV R2, 04H TEL2: MOV A, @R0 MOV @R1, A DEC RO DEC R 1 DJNZ R2, TEL2 MOV 4BH, 00H MOV 4AH, 00H MOV 49H, 00H MOV 48H, 00H MOV 5CH, 00H。 MOV 5DH, 00H MOV 5EH, 00H MOV 5FH, 19H LCALL DIVD1 MOV 22H, 4DH。 MOV 21 H, 4EH MOV 20H, 4FH LCALL HEXBCD2。 MOV LED8, 0AH。 LCALL DISP。 RET 。測占空比子程序 TESZKB: MOV R4, 02H TELI: LCALL PWZJS DJNZ R4, TEL I SETB MOV R0, 3FH MOV R l, 4FH MOV R2, 04H TEL4: MOV A, @R0 MOV @R I, A DEC RO DEC R 1 DJNZ R2, TEL4 MOV R0, 57H MOV RI, 5FH MOV R2, 04H TEL3: MOV A, @R0 MOV @Rl, A DEC R0 DEC R1 DJNZ R2, TEL3 LCALL ADDMB MOV R0, 5FH MOV R1, 3FH MOV R2, 04H TEL7: MOV A, @R0 MOV @R I， A DEC R0 DEC R1 DJNZ R2, TEL7 MOV 5CH, 00H MOV 5DH, 00H MOV 5EH, 03H MOV 5FH, 0E8H LCALL MULNM MOV R0, 5FH MOV R1, 4FH MOV R2, 04H TEL5: MOV A, @R0 MOV @R1, A DEC R0 DEC RI DJNZ R2, TEL5 MOV R0, 3FH MOV Rl, 5FH MOV R2, 04H TEL8: MOV A, @R0 MOV @RI, A DEC RO DEC R1 DJNZ R2, TEL8 MOV 48H, 00H MOV 49H, 00H MOV 4AH, 00H MOV 4BH, 00H LCALL DIVDI MOV 22H, 4DH。 MOV 21 H, 4EIH MOV 20H, 4FH LCALL HEXBCD2 MOV LED8, OBH?！?B， LCALL DISP。 RET PWZJS: SETB SETB CHOICE。 SETB TF JNB , PWL1 SETB START CLR LJMP PWL2 PWL1: CLR START PWL2: SETB CLRTRIG CLR CLRTRIG。 MOV Rl, OFH。 PWL3: LCALLTIS DJNZ R1, PWL3 PL0: JNB , PLO MOV A, R4 CJNE A, 02, PL2 MOV R0, 3FH MOV R3, 04H。 PLI: MOV A, PO MOV @R0, A DEC RO MOV A, P2 INC A MOV P2, A DJNZ R3, PL 1 LJMP NEXT6 PL2: MOV R0, 57H MOV R3, 04H PL3: MOV A, P0 MOV @R0, A DEC R0 MOV A, P2 INC A MOV P2, A DJNZ R31 PL3’ LOPP 1: MOV @R0, A INC RO DJNZ R7, LOPPI MOV R7, 18H LOOP4: MOVRI, 20H MOV R6, 03H CLR C LOPP2: MOV A, @R1 RLC A MOV @R1, A INC R 1 DJNZ R6, LOPP2 MOV R5, 04H MOV R0, 23H LOOP3: MOVA, @R0 ADDC A, @R0 DA A MOV @R0, A INC R0 DJNZR5, LOOP3 DJNZR7, LOOP4 SBCD: MOV R0, 23H MOV R1, 40H MOV R3, 04H HEM: MOV A, @R0 ANL A, OFH MOV @R I, A INC R I MOV A, @R0 ANL A, 0F0H SWAP A MOV @R1, A INC R1 INC R0 DJNZ R3, HEM MOV A, 47H CJNE A, 00H, HEX3 CLR MOV R0, 40H MOV R1, LED1 MOV R2, 07H HEX4: MOV A, @R0 MOV @R1, A INC RO INC R1 DJNZ R2, HEM LJMP NEXT2 HEX3: SETB MOV R0, 47H MOV R1, LED7 MOV R2, 07H HEX2: MOV A, @R0 MOV @R1, A DEC RO DEC R1 DJNZ R2, HEX2 NEXT2: RET DIVD1: NOP MOV AD0, 08H。