Hi, I'm working on a boot loader project with some
SRAM, EEPROM and AT89C52 and I want to ask you guys some things that I coudn't
find in any tehnical spacifications. For instance, if the /EA-Vpp
pin is on "1", procesor will execute program from internal code memory ( in this
case 8Kb ) and then countinu using external memory up to 64Kb ! If the /EA-Vpp
is on "0" procesor will read program code from external memory only ( 0x0000 -
0xFFFF ). The question is: What will heppn if I change /EA-Vpp pin from "1"
to "0" while the program is executing comands from internal code memory? (
If I change it while internal program is running )
My presupposition is that the program will continue
executing code from the PC ( program counter ) address of the external memory
code and if it's not right sincronized it will gone mad. Or it will countinue
doing it's program from internal 8Kb code memory and afther next reset it will
start from 0x0000 of external code memory.
If enyone has some experiance with these
things I would be more than grateful.
Sincerly Srdjan
Ridanovic