Digital Electronics - The 8051 Microcontroller - Discussion

**ROM called as Program memory use to store code / program.
->ROM is divided into internal and external memory portion in side 8051mc .
->Internal=4kbytes (0000- 0FFF ), External=60Kbytes(1000-FFFF ). Total = 64Kbytes(0000-FFFF).

-> EA( External Access) pin of 8051mc (pin no-31) use for point to Internal or External memory.
->when EA = 0(low) means EA = 1 or External Access = 1 = external memory use.
-->when EA = 1(high) means EA = 0 or External Access= 0 = Internal memory use.

1) If EA is acting high means we are using internal memory.

2) If EA is low -we are indicating the controller to use external rom.

Because when external access is high means "0" because showing bar so it can access only internal memory thats why pc points internal code memory.

When EA=0 no interrupt will be acknowledged but Im confused because they are saying EA bar is high.

Why the answer is internal code memory? but why can't internal data memory.

Because pc always points to code memory.

[a] internal code memory :Ram location means PC
[B]. external code memory :Rom location (EA=0,PSEN=CONNECT)
[C]. internal data memory :I think Rom location
[D]. external data memory :Rom location (EA=0,RD=CONNECT)

What will be the answer when EA bar is low?

When EA pin is low it use internal code memory.

But when EA pin is high use for external code memory.

But starting address 0x0000H to 4K use internal then use external memory.

When it goes high the internal ROM memory will be executed then answer should be C.