I wrote a small arduino program to read characters from the serial port and display them on the LoL Shield. Note that I had to edit the Charlieplex.cpp file from the LoLShield library to remove a (apparently unused) Serial.end() call. Line 373 on my copy.
Once the program is uploaded to your ATmega on the Gertboard, you can deliver text via serial on the Pi using any method you like, e.g. interactively via one of:
- minicom ama0
- screen /dev/ttyAMA0 9600
Alternatively, you can send your text programmatically via a python, C, bash script by writing to the /dev/ttyAMA0 device, e.g.:
- $ echo 'weeee!' > /dev/ttyAMA0
Remember, when sending/receiving serial data between the Pi and the Gertboard's ATmega, you must connect the GP14-15 pins in J2 to the MCTX and MCRX pins just above them.
// displays text sent via serial e.g.
// echo 'weeee!' > /dev/ttyAMA0
//
#include "Charliplexing.h"
#include "Myfont.h"
#include "Arduino.h"
unsigned char buffer[140];
int c;
int i = 0;
int len;
void setup() {
Serial.begin(9600);
LedSign::Init();
}
void doMsg() {
Myfont::Banner(len, buffer);
}
void loop() {
if(Serial.available()) {
int c = Serial.read();
if(c != -1) {
if(c == '\n' || c == '\r') {
buffer[i] = '\0';
len = i;
i = 0;
doMsg();
} else {
buffer[i++] = c;
}
}
} else {
if(len > 0) {
doMsg();
}
}
}
