spiMaster6.ino 1802 two nano system start

// Based on Code Written by Nick Gammon// February 2011
//TPA and B reading well from 1802. Now reading address from MA0..MA7 directly.Wed Jul  1 12:20:36 NZST 2020
/*Sat Jul  4 13:29:59 NZST 2020. C:\Users\Dell\Documents\Arduino\PB_Sketches_May20\spiMaster6\spiMaster6.ino

*/
#include <SPI.h>
 //byte adrHi,adrLo;
#define TPAPin 8
#define TPBPin 9
byte   adrHi=0x12;
byte adrLo=0x34;
void setup (void)
{
Serial.begin (115200);
	pinMode(TPAPin,INPUT);
	pinMode(TPBPin,INPUT);
	DDRD=0x0;
	DDRC=0x0;
 pinMode(SS, OUTPUT);
  Serial.begin (115200);   // debugging
  //togSS();
  //TPLoop() ;
  digitalWrite(SS, HIGH);  // ensure SS stays high for now

  // Put SCK, MOSI, SS pins into output mode
  // also put SCK, MOSI into LOW state, and SS into HIGH state.
  // Then put SPI hardware into Master mode and turn SPI on
  SPI.begin ();

  // Slow down the master a bit
  SPI.setClockDivider(SPI_CLOCK_DIV8);

}  // end of setup


void loop (void) {

		if (digitalRead(TPAPin)==HIGH) {
			doTPAStuff();
		}
		if (digitalRead(TPBPin)==HIGH) {
			doTPBStuff();
		}
}

 void SPITx2(void) { //send two adresses via spi
	digitalWrite(SS, LOW);    // SS is pin 10
	SPI.transfer(adrHi);
	delayMicroseconds(8); //2 microsecond delay seems to work but not 1 uS. Check with nano when this comes up.
	SPI.transfer(adrLo);
	digitalWrite(SS, HIGH);
}  // -------------------end of loop

/*void togSS(void) {
  while(true) {
    digitalWrite(SS,HIGH);
    delay(1000);
    digitalWrite(SS,LOW);
    delay(1000);
  }
}
  void TPLoop(void) {
	while(true) {
		if (digitalRead(TPAPin)==HIGH) {
			doTPAStuff();
		}
		if (digitalRead(TPBPin)==HIGH) {
			doTPBStuff();
		}
	}
}*/
void doTPAStuff(void) {
	byte lowNib = PINC & 0x0f;
	byte hiNib = PIND & 0xf0;
	while(digitalRead(TPAPin) ==HIGH) {  }; //do nothing
	 adrHi = hiNib | lowNib;		//transfer later during TPB
	Serial.print("A..");Serial.println(adrHi,HEX);
}
void doTPBStuff(void) {
	byte lowNib = PINC & 0x0f;
	byte hiNib = PIND & 0xf0;
	while(digitalRead(TPBPin) ==HIGH) {  }; //do nothing
	 adrLo = hiNib | lowNib;
	Serial.print("B,,");Serial.println(adrLo,HEX);
	SPITx2();		//send adrHi and adrLo to Nb
}