An Experimentation on SRAM chips.

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An Experimentation on SRAM chips.

Postby Brian Griffin » Wed Jun 27, 2012 12:26 pm

Project Name: An Experimentation on SRAM chips.

Project Description: Once in your whole life with your computers, you must have upgraded your RAM in your PC. Put a 4GB DDR3, or even more. Not enough? Put more!

In microcontroller systems, RAMs are quite scarce and very limited. A 4KB RAM inside one of these is considered a lot for an 8bit. Many years back, computer memory are expensive, and even a 512KB is like, huge for a computer back in the 80s.

Here it is shown that a parallel SRAM is used as an extra RAM space for a microcontroller board. Unfortunately, I am not able to get a lot of pins from a casual 40-pin PIC, so another microcontroller board is used to demonstrate the interfacing of the SRAM.

In the software, the system tests the RAM for presence, and then test each register in the RAM by testing each bit inside. If the RAM is not present, an error is shown, and if the RAM has problems in the data registers, an error is shown with the offending address.

Hardware: 62256 SRAM, MikroElektronika LV18F v6 board, a lot of jumper wires (27 and above), 16x2 44780 LCD, breadboard.

62256ramtestboard.jpg
Testing the RAM.


Software: MikroC v5.60 (can be compiled within demo limit!)

Source code: Attached

References: http://www.esacademy.com/en/library/technical-articles-and-documents/miscellaneous/software-based-memory-testing.html

Note: The SRAM must be connected to +5V or else errors will occur!

I'll get it running on a PIC32. And due to the instruction cache inside, it's too fast for the external SRAM itself. I will use its PMP for this one instead. :)
Attachments
pic18f-sramtest.zip
Source Code.
(52.4 KiB) Downloaded 417 times
PIC - UIC00B from Cytron (replacement for my broken PICKit 2), Pickit 3, MikroC for PIC
dsPIC - MikroC for dsPIC, mikromedia board (dsPIC33)
AVR - AVR Dragon
Parallax - Prop tool
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Brian Griffin
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Re: An Experimentation on SRAM chips.

Postby sich » Fri Jun 29, 2012 2:00 am

Just notice this project... it certainly is a good get started guide for those who wants to use SRAM in mcu. Nice :!:
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