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is there anyone who knows bank swith of 8051?

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gogogo

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8051 bank switching

is there anyone who knows bank switch of 8051?
you know the largest address area is 64K,
how can i expand the address area,
as i know , through bank switch can,
but how do i do by this method?
is there any stuff introducing it??
thx
 

farhada

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swith of

Hi,
If my memory is correct, IAR's C compiler had support for Bank Switching. The method they used was to use 2 or more pins of one of the IO ports to handle the physical addressing of the data and they had a special library to controll the access.

You can write your own code to handle the data. There are many different ways of doing it, hopefully someone has already the code for you here.

BR,
/Farhad
 

bsiswoyo

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iar compiler banked model 8051

gogogo said:
is there anyone who knows bank switch of 8051?
you know the largest address area is 64K,
how can i expand the address area,
as i know , through bank switch can,
but how do i do by this method?
is there any stuff introducing it??
thx

The principles is:
Use additional port as chip select for bank.

For example if you will expand 8 chip of 64KB RAM.
16 Address line use P0 and P2 (as default) is connected to 16 bit address line of RAM.
Use 3 bit additional from P1 or P3 (example P1.0, P1.1 and P1.0) and connect to 3-8 decoder. The output of decoder is connected to each Chip Select of RAM.
In main program must be initiated the P1.0, P1.1, P1.2 all to 0's to select the first chip.
If you select the another chip, set P1.0, P1.1, P1.2 as you need.
 

silvio

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8051 p1.1 p1.0

gogogo said:
is there anyone who knows bank switch of 8051?
you know the largest address area is 64K,
how can i expand the address area,
as i know , through bank switch can,
but how do i do by this method?
is there any stuff introducing it??
thx

A nice explanation:
https://www.maxim-ic.com/appnotes.cfm/appnote_number/549

549Fig05.gif


549Fig06.gif


and software:

ftp://ftp.dalsemi.com/pub/microcontroller/app_note_software/an81_sw.exe
Self-extracting file demonstrating methods for expanding memory beyond 64 KB.
BANKJMP1.asm: Demonstrates common-page memory expansion configuration using I/O.
BANKJMP2.asm: Demonstrates common-page memory expansion configuration using latched addressing.
 

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