Tech Blog

/*
 * PD2437 Test
 */

/*

 - Addressing
  0xx : control word
  100 : digit 0 (rightmost)
  101 : digit 1
  110 : digit 2
  111 : digit 3 (leftmost)

 - Control Word
  b7 : clear
       0 standard operation
       1 clear entire display
  b6 : lamp test
       0 standard operation
       1 display all dots at 50% brightness
  b5 : blink
       0 blink attribute disabled
       1 blink entire display
  b4 : attribute enable
       0 disable above attributes
       1 enable above attributes
  b3,b2: attributes
       00 display cursor instead of character
       01 blink character
       10 display blinking cursor instead of character
       11 alternate character with cursor
  b1,b0: brightness
       00 0% (black)
       01 25%
       10 50%
       11 100%
      
  -----------------------------------------------------
  how to load information into the display
 
    SET BRIGHTNESS
  1. set brightness level of the entire display to your preference, (000) <- 0x02 (50%)
   
    LOAD FOUR CHARACTERS
  2. load "S" in the left hand digit, (111) <- 'S'
  3. load "T" in the next digit, (110) <- 'T'
  4. load "O" in the next digit, (101) <- 'O'
  5. load "P" in the right hand digit, (100) <- 'P'
 
    BLINK A SINGLE CHARACTER
  6. into the digit, second from the right, load the hex code 0xcf, which is the code for an 'O' with the d7 bit added as a control bit, (101) <- 0xcf
  7. load enabled blinking character into the control word register. the display should show "STOP" with a flashing "O", (000) <- 0x17
 
    ADD ANOTHER BLINKING CHARACTER
  8. into the left hand digit, load the he code 0xd3 which gives an 'S' with d7 bit added as a control bit, (111) <- 0xd3
 
    ALTERNATE CHARACTER/CURSOR ENABLE
  9. load enable alternate character/cursor into the control word register. the display now should show "STOP" with the 'O' and the 'S' alternating between the letter and cursor. (000) <- 1f
 
    INITIATE FOUR CHARACTER BLINKING
  10. load enable display blinking. the display now should show the entire word "STOP" blinking, (000) <- 0x23
*/

// Connected to LS164
int DATA = 2;    // LS164 Din  (pin 1&2)
int CLK = 3;     // LS164 Clk  (pin 8)

// Connected to PD2437
int A0 = 6;   // Address 0 (pin 7)
int A1 = 5;   // Address 1 (pin 8)
int A2 = 4;   // Address 2 (pin 9)

int WR = 7;   // Write (pin 11)
int CE = 8;   // Chip Enable (NEG, pin 6)
int RST = 9;  // Reset (NEG, pin 4)

void setup()                    // run once, when the sketch starts
{
  Serial.begin(38400);
 
  // pins for LS164
  pinMode(DATA, OUTPUT);      // sets the digital pin as output
  pinMode(CLK, OUTPUT);      // sets the digital pin as output
 
  // pins for PD2437
  pinMode(A0, OUTPUT);
  pinMode(A1, OUTPUT);
  pinMode(A2, OUTPUT);
  pinMode(WR, OUTPUT);
  pinMode(CE, OUTPUT);
  pinMode(RST, OUTPUT);
 
  // Reset PD2437
  digitalWrite(CE, HIGH);
  digitalWrite(WR, HIGH);

  digitalWrite(RST, LOW);
  digitalWrite(RST, HIGH);
}

void loop()                     // run over and over again
{
  putChar(0, 0x83);
  delay(100);
  putChar(7,'S');
  delay(100);
  putChar(6,'T');
  delay(100);
  putChar(5,'O');
  delay(100);
  putChar(4,'P');
  delay(100);
 
  putChar(4, 'P' | 0x80);    // 'P' w/ MSB
  delay(100);
  putChar(0, 0x17);
  delay(100);
  putChar(7, 'S' | 0x80);    // 'S' w/ MSB
  delay(100);
  putChar(0, 0x1f);
  delay(100);
  putChar(0, 0x23);
 
  delay(1000); 
}

//
// Subroutine for LS164
//

// Send byte to LS164
void sendByte(int d)
{
  shiftOut(DATA, CLK, MSBFIRST, d);
}

//
// Subroutine for PD2437
//

// set address for PD2437
void setAddr(int adr)
{
  digitalWrite(A0, (adr&0x1));
  digitalWrite(A1, (adr&0x2));
  digitalWrite(A2, (adr&0x4));
} 

void putChar(int pos, int ch)
{
  digitalWrite(CE, LOW);

  setAddr(pos);
  sendByte(ch);
  digitalWrite(WR, LOW);
  digitalWrite(WR, HIGH); 
  digitalWrite(CE, HIGH);
}