Lots Of Leds Shield Project

This is a simple example project for the 3rd party LOL shield board for the RX63N GR-Sakura board.

The board is supplied by OLIMEX (www.OLIMEX.com) has 120 3mm Green LEDS mounted in a 14 x 9 configuration

The example project is built on the standard Sakura library configuration with these additional files added to the project
Charlieplexing.cpp, LOLDraw.cpp intvec.c and gr_sketch.cpp together with the associated header files for these functions.


This function provide the interface and LED position decoding to the LOL board using the "charlieplexing" multiplex technique for driving matrix LED board
It also contains the Timer interrupt routine (TMR0 CMIA)


This function provides some basic drawing function such as Line, circle Point and rectangle which are used together with the Charlieplexing functions

The gr_sketch.cpp file provides the main project examples of these functions


Main project file containing the example usage for LED output

The functions included are

  1. Diagonal write from left to right starting from the top left LED.
  2. Vertical write from left to right, starting from the left hand colomn
  3. Line draw examples
  4. Rectangle draw examples
  5. Circle draw examples


Standard interrupt vector table file modified to eliminate the duplicate declaration error for Timer 0 ISR

Just replace this file with the standard one in the GR-Sakura project files (or modify the with the changes in this file)

Project Setup

The Zip file (LoL Example.zip) downloaded contains all the files to reproduce this project. Just replace the standard files with the ones in the zip file and add the new files to a new project and build

The binary file is provided so that a configuration can be tested without having to create and build a project first


There are a few points to consider when using the Olimex LED board with the GR-Sakura

1. Extender connectors are needed to raise the LED shield board above the Ethernet connector

2. It is necessary to isolate a pull up resistor on the Sakura board connected to CPU pin PC7 (RP4 pin 4. See page 3of the GR-Sakura board schematic ) this is one of the LED board drive pins which is also used by the SD card function

3. The standard interrupt file needs to be edited to avoid a duplication error for the the timer ISR being generated when building the project. The modified "intvec.c" file is included in the Zip file


My thanks to Ian Hall of Renesas for his assistance with this project