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using external memory and internal memory of 89c51

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grittinjames

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i having a doubt how we can use external memory along with internal 4k .

wt i shuld do EA pin in this condition.
 

if you just need more program memory try using different micro
many mfg and types for 8051 family

DS89C450 from maxim has 64k program flash memory **broken link removed**
DS89C330 has 16k program (also have simple serial bootstrap loader)

im not sure if you leave EA high and then exceed 4k memory the micro will
then go to external memory. try it

if you tie EA low then all program memory will be external

or do you need more RAM ?
just exceed the RAM address in 89c51 and micro will go to external memory
 

Any 8051-derivative, including 89C51/2/3 (and so on), automatically switches from the internal program memory to the external program memory as soon as the address register of the internal memory is overflown (don't worry about the EA pin - leave it "H") ..


Regards,
IanP
 

    grittinjames

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