You know, 8282 is much easier to connect than 373. However, 573 just came to my attention after 8282 was practically applied. I may replace 8282 with 573 as soon as I get one. 8282 really costs more.

I have tried another way to read RAM. That is :

1. connect /G of 8282 to P3.0 so I can control it manually.

2. /WE of 62256 to /WR of 8052
/OE of 62256 to /RD of 8502
/CE of 62256 to GND

3. codes:

MOV P0,#55H ;A0-A7=0x55
MOV P2,#0AAH ;A8-A15=0xAA
CLR P3.0 ;8282 LATCH ENABLED
CLR P3.7 ;/RD ENABLED
MOV P0,#0FFH ;RESET PORT
MOV P1,P0 ;READ DATA

4. P1 appeared with nothing, so did P0. I have tested address bus, which is exactly 0x55AA.

Anything wrong?