Monday, April 16, 2012

Simple 8bit digital data logger using PIC16F887

This is an example application for our "Extend PIC Microcontroller‘s RAM by without using EMI" blog post. In this system PIC16F887 microcontroller is interface with four units of UM61512AK – 64K × 8 CMOS SRAMs. Monitoring signal is supplied to the MCU through “PORT A” and all the communications are performing through RS232 interface.

In my previous post most of the readers ask me about pure C language routine(s) for memory access. To fulfill that request I rewrite both memory read and write operations using C programming language. Compared with the previous Assembly language routines, only performance glitch in this implementation is 16bit address decoding part (which consume some CPU cycles than assembly language implementation)

With this given firmware user can operate this system by without installing any driver software in the host side. All the data capturing and reporting operating are done by MCU itself.

Originally I design this data logger to do some photometric data logging. To generalize and to simplify I remove photo-detection and low voltage amplifier from this design.

This is an open hardware project. All the firmware source codes are released under the terms of GNU Lesser General Public License (LGPL) 3.0 and all the documents and other resources are released under the terms of Creative Commons Attribution-ShareAlike 3.0 Unported License. Downloadable content of this article are available at google drive.