Shift register help.

Projects General Guidance
2

Use the Arduino's SPI hardware:

#Include<SPI.h>
byte ssPIN = 10;
byte testData = 0xAA;  // test data
void setup(){
pinMode (ssPIN,  OUTPUT);
digitalWrite (ssPin, HIGH);
}
void loop(){
digitalWrite (ssPin, LOW); // RCLK
SPI.transfer(testData); // SCK to SRCLK, MOSI to SER In. OE Low, MRCLR HIGH
digitalWrite (ssPin, HIGH);
}