Code indirect

External memory can also be accessed using a form of indirect addressing which is called as code indirect addressing. This form of addressing is usually only used in relatively small projects that have a very small amount of external RAM. An example of this addressing mode is: -

 MOVX @R0, A

 Once again, the value of R0 is first read and the value of the Accumulator is written to that address in External RAM. Since the value of @R0 can only be 00h through FFh the project would effectively be limited to 256 bytes of External RAM. There are relatively simple hardware/software tricks that can be implemented to access more than 256 bytes of memory using External Indirect addressing; however, it is usually easier to use External Direct addressing if your project has more than 256 bytes of External RAM.

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