How to interface sram with 8051 ?

[sankalani2003]

how to interface sram with 8051 .
i have ds80c320 (mc) and ds1245 sram chips.

 

[IanP]

Re: 8051 + sram

The 8051 basic core can address only 64kB of external data memory ..
If you need to address more than that - you will have to do it "by hand" ..
As the DS1245 is an 128kB RAM you will have to divide it into two 64-kB halves and using any free general purpose pin (P1.0, P1.1 and so on) connected to A16 select/switch between both 64kB (2*64kB=128kB) banks ..
Otherwise all standard rules of connecting an external memory to the 8051-derivative apply (74373 as address latch etc. etc.) ..
See:
**broken link removed**

Regards,
IanP

 

[laktronics]

Re: 8051 + sram

Hi,
Assuming that you know generally as to how to connect external devices to 8051 external bus, you connect the static Ram as follows:
1. Use an HC 373 on data bus of the controller , to separate low order address bytes using ALE and connect the output of HC373 to A0 to A7 low order address bus of RAM.
2. Connect A8 to A15 lines of RAM to matching port 2 bits of the controller.
3. Pull up the data data bus of the controller with a 4.7K resistor network to Vcc.
4. Connect the controller data bus to the RAM data bus.
5. Connect OE bar and WR lines of RAM to RD and WR lines of the controller.
6. Connect any unused port pin (say P1.0) of the controller to A16 pin of RAM to select memory as two 64k Banks.
7. Ground CE pin of RAM.

And there you go, your RAM is interfaced to the controller and start using it.

Regards,
Laktronics