A B 8051 in circuit debugger based on AT89C51 Chin-Shiuh Shieh 1999/11/21 11.0592M 20p 74373 1 2 3 4 5 6 7 8 9 10 /OC 1Q 1D 2D 2Q 3Q 3D 4D 4Q GND 1 2 3 4 5 6 7 8 9 10 11 12 13 14 +5V 20 19 18 17 16 15 14 13 12 11 Vcc 8Q 8D 7D 7Q 6Q 6D 5D 5Q CK A14 A12 A7 A6 A5 A4 A3 A2 A1 A0 I/O0 I/O1 I/O2 Vss Vcc /WE A13 A8 A9 A11 /OE A10 /CS I/O7 I/O6 I/O5 I/O4 I/O3 +5V 28 27 26 25 24 23 22 21 20 19 18 17 16 15 1 2 In Circuit Socket 20p 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 3 62256 P1.0 VCC P1.1 P0.0(AD0) P1.2 P0.1(AD1) P1.3 P0.2(AD2) P1.4 P0.3(AD3) P1.5 P0.4(AD4) P1.6 P0.5(AD5) P1.7 P0.6(AD6) RST P0.7(AD7) P3.0(RXD) /EA(VPP) P3.1(TXD)ALE(/PROG) P3.2(/INT0) /PSEN P3.3(/INT1) P2.7(A15) P3.4(T0) P2.6(A14) P3.5(T1) P2.5(A13) P3.6(/WR) P2.4(A12) P3.7(/RD) P2.3(A11) XTAL2 P2.2(A10) XTAL1 P2.1(A9) GND P2.0(A8) 40 39 38 37 36 35 34 33 32 31 30 29 28 27 26 25 24 23 22 21 7408AND 1 2 3 4 5 6 7 1A Vcc 1B 4A 1Y 4B 2A 4Y 2B 3A 2Y 3B GND3Y +5V 14 13 12 11 10 9 8 1u 1u 1u 1 2 3 4 5 6 7 8 Vout = 5V DC 7805 IN OUT GND 3 Power Link HIN232 1u +5V Vin > 7V DC 330 2 +5V 40 39 38 37 36 35 34 33 32 31 30 29 28 27 26 25 24 23 22 21 330 8.2k RESET P1.0 VCC P1.1 P0.0(AD0) P1.2 P0.1(AD1) P1.3 P0.2(AD2) P1.4 P0.3(AD3) P1.5 P0.4(AD4) P1.6 P0.5(AD5) P1.7 P0.6(AD6) RST P0.7(AD7) P3.0(RXD) /EA(VPP) P3.1(TXD)ALE(/PROG) P3.2(/INT0) /PSEN P3.3(/INT1) P2.7(A15) P3.4(T0) P2.6(A14) P3.5(T1) P2.5(A13) P3.6(/WR) P2.4(A12) P3.7(/RD) P2.3(A11) XTAL2 P2.2(A10) XTAL1 P2.1(A9) GND P2.0(A8) E 10u 10u +5V AT89C51 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 D 100u 1 C C1+ Vcc V+ GND C1- T1out C2+ R1in C2- R1out VT1in T2out T2in R2in R2out +5V 16 15 14 13 12 11 10 9 RS232 Connector 1 2 3 4 5 CD DSR 6 RD RTS 7 TD CTS 8 DTR RI 9 GND 4 4 A B C D E