Sending information to display drivers

Forum 2005-2010 (read only) Software Syntax & Programs
1

Hi, I'm a very inexperienced Arduino user and I'm trying to send data to a display driver to make a 4 segment display light up. Its not working at the moment and is most likely that I've coded something incorrectly. The display driver I'm using is a SAA1064, here's my code.

The text on the monitor and the flashing LED is just to tell me whether the program is going through the loop ok (and it does). I took the byte writing part from a guide on the playground. Any help or suggestions would be most welcome! Thanks.

//Declaration of variables

int clock = 0;
int dataIn = 1;
int led = 13;

void setup(){
  Serial.begin(9600);
  Serial.println("Hello world!");
  pinMode(clock, OUTPUT);
  pinMode(dataIn, OUTPUT);
  pinMode(led, OUTPUT);
  
}

void loop(){
  Serial.println("Test1");
  flash();
  putByte(0x76);           //slave address
  flash();
  Serial.println("Test2");
  putByte(0x00);           //instruction byte
  flash();
  Serial.println("Test3");
  putByte(0x0F);           // control byte
  flash();
  Serial.println("Test4");
  putByte(0xE4);           //data digit 1
  flash();
  Serial.println("Test5");
  putByte(0xE4);           //data digit 2
  flash();
  Serial.println("Test6");
  putByte(0xE4);           //data digit 3
  flash();
  Serial.println("Test7");
  putByte(0xE4);           //data digit 4
  flash();
  Serial.println("Test8");
  delay(10000);  
}

void putByte(byte data) {
  byte i = 8;
  byte mask;
  while(i > 0) {
    mask = 0x01 << (i - 1);      // get bitmask
    digitalWrite( clock, LOW);   // tick
    if (data & mask){            // choose bit
      digitalWrite(dataIn, HIGH);// send 1
    }else{
      digitalWrite(dataIn, LOW); // send 0
    }
    digitalWrite(clock, HIGH);   // tock
    --i;                         // move to lesser bit
  }
}

void flash(){
  delay(1000);
  digitalWrite(led, HIGH);
  delay(1000);
  digitalWrite(led, LOW);
  delay(1000);
  digitalWrite(led, HIGH);
   delay(1000);
  digitalWrite(led, LOW);
}
2

Hi,

Hi, I'm a very inexperienced Arduino user and I'm trying to send data to a display driver to make a 4 segment display light up. Its not working at the moment and is most likely that I've coded something incorrectly. The display driver I'm using is a SAA1064, here's my code.

I'm sorry but you are completely on the wrong track with your code...

The SAA1064 uses the I2C-bus (or TWI which is the same thing different branding)

But the arduino supports this too!
Read about the Wire-lib here Wire \ Libraries \ Wiring
I don't know if anybody used the SAA1064 with the arduino before
Check the arduino-pages for wire-lib and I2C or TI or IIC to find out more
Eberhard

3

Thanks for the help wayoda, have been looking at the wire library but is quite confusing! Unfortunately a search of TWI or I2C reveals nothing on the syntax and programs part of the forums.

Here's what I've got so far anyway, any help or links appreciated:

#include <Wire.h>

int led0Pin = 10;   // select the pin for red 'test' LED

void setup() {
  Wire.begin();
  Serial.begin(9600);                 // set serial speed
  Serial.println("Hello world!");     // check board setup ok
  pinMode(led0Pin, OUTPUT);           // declare the led0Pin as an OUTPUT
}

void loop() {
  
  digitalWrite(led0Pin, HIGH);  // turn the ledPin on
  delay(1000); 
  
  Wire.beginTransmission(0x76);
  Wire.send(0x76); //slave address
  Wire.send(0x00); //instruction byte
  Wire.send(0x0F); //control byte
  Wire.send(0xE4); //data digit 1
  Wire.send(0xE4); //data digit 2
  Wire.send(0xE4); //data digit 3
  Wire.send(0xE4); //data digit 4
  Wire.endTransmission();
    
  digitalWrite(led0Pin, LOW);  // turn the ledPin on
  delay(1000); 

}
4

Hi,
this looks basically OK...

Did you get the Address right, (can be configured by the hardware to three other ones)
I guess you see nothing? (You know you send command : DisplayTest)
Did you get the wiring right? The SCL-Signal is on the Arduino AnalogIn 5 SDA AnalogIn 4 I think..

Add "arduino twi" "arduino i2c" to your search to see more examples of how to use the wiring library
Eberhard

5

For some reason the address needs to be half that of what it says on the data sheet!

6

(it's working in case you hadn't gathered from the previous post!) :slight_smile: