CLK RL7 157 146 RL 135 RLs 124 A RLa 11 ALE 74LS373 RL3 10 2 8051 RL 9 1 P 0 P0.0 D0 RLI P0.1 DI RLo P0.2 2 SLo P0.3 D3 SLI 74LS BIC P0.4 D4 SL2 38 8708 P0.5 D5 8279 Yo-Y P0.6 D6 0p2.7 D7 日.日.日.日.日.日.日.日 W WR +5V a bc d e f g dp RD RD 5555 NTI IRQ BIC 20u 8708 RESET CNTL SHIFT A +5V D 0 D 1 D 2 D 3 D 4 D 5 D 6 D 7 P 0 . 0 P 0 . 1 P 0 . 2 P 0 . 3 P 0 . 4 P 0 . 5 P 0 . 6 P 0 . 7 ALE P2.7 RD INT 1 8051 RL 7 RL 6 RL 5 RL4 RL 3 RL2 RL 1 RL 0 CLK A0 WR RD IRQ 74LS373 RESET SHIFT CNTL 20µF + 5 V 2 K SL 0 SL 1 SL2 8279 74LS1 38 Y 0~Y 7 VCC+5 V 15 14 13 12 11 1098 76543210 BIC 8708 dp BIC 8708 + 5 V a b c d e f g B 0 B 1 B 2 B 3 A0 A1 A2 A3 CS WR