How to access the external memory ?

[sacrpio]

External Memory Access..

We acces external memory using XDATA in Keil C. Is there any other method to acess the external memory.

thanks

 

[aamiralikhoja]

Re: External Memory Access..

u can use inline assembly put address in DPTR and access the byte or

use xbyte[address] = value

value = xbyte[address]

learn more the final word on 8051 microcontroller

 

[bsiswoyo]

Re: External Memory Access..

We acces external memory using XDATA in ke*il C. Is there any other method to acess the external memory.

thanks

for example define memory at xram as:
var_int as integer
var_char as char
var_long as long

address begin 8000H:
8255_PortA as char
8255_PortB as char
8255_PortC as char
8255_PortCR as char


you must declare as:

int xdata var_int;
char xdata var_char;
long xdata var_long;

char xdata 8255_PortA _at_ 0x8000;
char xdata 8255_PortB _at_ 0x8001;
char xdata 8255_PortC _at_ 0x8002;
char xdata 8255_PortCR _at_ 0x8003;

To assign and read data to/from variable like you write in C programming.

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