You can connect 8052 to an ISA bus only when using some interface circuits. ISA bus is to fast for a standard 8052 (ISA bus speed is 8 MHz). You can use a pheripherial interface like PPI 8255 or some latches like HC374, HC377 or similar to write to and some transceivers like HC244, HC245 to read.
You then write to output port of PPI or output latch a command or data that 8052 can read and you read from ISA a transceiver that is connected to an output port of 8052.

There is a must to adapt hight speed of the ISA bus to a slow speed of 8052 output port using some interface circuits.

There was a project described in the magazine ELEKTOR electronics some time ago on PC printer buffer card where 8051 was used in a PC insertion card. An interface ISA<-->8052 was a standard centronics interface circuit 82C11.