Hallo,
ich habe derzeit 3 74hc165 hintereinander hängen und an den chips hängen taster die Leds steuern.
Bei 2 Chips funktionieren alle 16 Eingänge wunderbar. Wenn ich im Programmiercode auf 3 umschalte läuft zwar der 3. Chip und der 2. aber der erste Chip läuft nicht mehr. Ich vermute ich habe ein Fehler in der Programmierung, weil sonst müsste der 3. Chip ja gar nicht funktionieren oder?
Hier mal der Code:
/*
* SN74HC165N_shift_reg
*
* Program to shift in the bit values from a SN74HC165N 8-bit
* parallel-in/serial-out shift register.
*
* This sketch demonstrates reading in 16 digital states from a
* pair of daisy-chained SN74HC165N shift registers while using
* only 4 digital pins on the Arduino.
*
* You can daisy-chain these chips by connecting the serial-out
* (Q7 pin) on one shift register to the serial-in (Ds pin) of
* the other.
*
* Of course you can daisy chain as many as you like while still
* using only 4 Arduino pins (though you would have to process
* them 4 at a time into separate unsigned long variables).
*
*/
/* How many shift register chips are daisy-chained.
*/
#define NUMBER_OF_SHIFT_CHIPS 3
/* Width of data (how many ext lines).
*/
#define DATA_WIDTH NUMBER_OF_SHIFT_CHIPS * 8
/* Width of pulse to trigger the shift register to read and latch.
*/
#define PULSE_WIDTH_USEC 5
/* Optional delay between shift register reads.
*/
#define POLL_DELAY_MSEC 1
/* You will need to change the "int" to "long" If the
* NUMBER_OF_SHIFT_CHIPS is higher than 2.
*/
#define BYTES_VAL_T unsigned long
#include "Tlc5940.h"
int ploadPin = 2; // Connects to Parallel load pin the 165
int clockEnablePin = 6; // Connects to Clock Enable pin the 165
int dataPin = 4; // Connects to the Q7 pin the 165
int clockPin = 5; // Connects to the Clock pin the 165
BYTES_VAL_T pinValues;
BYTES_VAL_T oldPinValues;
/* This function is essentially a "shift-in" routine reading the
* serial Data from the shift register chips and representing
* the state of those pins in an unsigned integer (or long).
*/
BYTES_VAL_T read_shift_regs()
{
byte bitVal;
BYTES_VAL_T bytesVal = 0;
/* Trigger a parallel Load to latch the state of the data lines,
*/
digitalWrite(clockEnablePin, HIGH);
digitalWrite(ploadPin, LOW);
delayMicroseconds(PULSE_WIDTH_USEC);
digitalWrite(ploadPin, HIGH);
digitalWrite(clockEnablePin, LOW);
/* Loop to read each bit value from the serial out line
* of the SN74HC165N.
*/
for(int i = 0; i < DATA_WIDTH; i++)
{
bitVal = digitalRead(dataPin);
/* Set the corresponding bit in bytesVal.
*/
bytesVal |= (bitVal << ((DATA_WIDTH-1) - i));
/* Pulse the Clock (rising edge shifts the next bit).
*/
digitalWrite(clockPin, HIGH);
delayMicroseconds(PULSE_WIDTH_USEC);
digitalWrite(clockPin, LOW);
}
return(bytesVal);
}
/* Dump the list of zones along with their current status.
*/
void display_pin_values()
{
Serial.print("Pin States:\r\n");
for(int i = 0; i < DATA_WIDTH; i++)
{
Serial.print(" Pin-");
Serial.print(i);
Serial.print(": ");
if((pinValues >> i) & 1)
Serial.print("HIGH");
else
Serial.print("LOW");
Serial.print("\r\n");
}
Serial.print("\r\n");
}
void setup()
{
Serial.begin(9600);
/* Initialize our digital pins...
*/
pinMode(ploadPin, OUTPUT);
pinMode(clockEnablePin, OUTPUT);
pinMode(clockPin, OUTPUT);
pinMode(dataPin, INPUT);
Tlc.init();
digitalWrite(clockPin, LOW);
digitalWrite(ploadPin, HIGH);
/* Read in and display the pin states at startup.
*/
pinValues = read_shift_regs();
display_pin_values();
oldPinValues = pinValues;
}
void loop()
{
/* Read the state of all zones.
*/
pinValues = read_shift_regs();
if(pinValues==0) {
Tlc.init(4095);
}
else{
//Tlc.init(0);
Tlc.clear();
Tlc.set(0,4095);
Tlc.update(); } /* If there was a chage in state, display which ones changed.
*/
if(pinValues != oldPinValues)
{
Serial.print("*Pin value change detected*\r\n");
display_pin_values();
oldPinValues = pinValues;
}
delay(POLL_DELAY_MSEC);
}
