Hi...!!
I am reading http://www.gammon.com.au/spi again and again and trying to grasp SPI, but not getting expected results.
Can we write the codes like this, are these correct codes for mater and slave
//Master sending data
#include <SPI.h>// include the SPI library:
#define SCK_PIN 13
#define MISO_PIN 12
#define MOSI_PIN 11
const int spidata = 10;//Pin 11 is data(MOSI) and pin 13 SCK ,set pin 10(SS) as the slave select for the digital pot:
int array[30] = {0x04, 0x00, 0x00, 0x00, 0x00, 0x00, 0x06, 0x00,0x00, 0x00, 0x00, 0x00, 0x08,0x00, 0x00, 0x00, 0x00, 0x00, 0x0A, 0x00, 0x00, 0x00, 0x00,0x00};
int chr;
void setup() {
pinMode (spidata, OUTPUT);// set the spi_data_pin as an output:
SPI.begin();// initialize SPI:
Serial.begin(115200);
SPI.setDataMode(SPI_MODE2);
SPI.setClockDivider(SPI_CLOCK_DIV64) ;
SPI.setBitOrder(LSBFIRST);
digitalWrite(spidata,HIGH);
}
void loop() {
int data[10];
char ch;
//delay(14);
digitalWrite(spidata,LOW);
SPI.transfer(array[0]);
SPI.transfer(array[1]);
digitalWrite(spidata,HIGH);
//delay(14);
digitalWrite(spidata,LOW);
SPI.transfer(array[2]);
SPI.transfer(array[3]);
digitalWrite(spidata,HIGH);
// delay(14);
digitalWrite(spidata,LOW);
SPI.transfer(array[4]);
SPI.transfer(array[5]);
digitalWrite(spidata,HIGH);
delay(1);
digitalWrite(spidata,LOW);
SPI.transfer(array[6]);
SPI.transfer(array[7]);
digitalWrite(spidata,HIGH);
digitalWrite(spidata,LOW);
SPI.transfer(array[8]);
SPI.transfer(array[9]);
digitalWrite(spidata,HIGH);
digitalWrite(spidata,LOW);
SPI.transfer(array[10]);
SPI.transfer(array[11]);
digitalWrite(spidata,HIGH);
delay(1);
digitalWrite(spidata,LOW);
SPI.transfer(array[12]);
SPI.transfer(array[13]);
digitalWrite(spidata,HIGH);
// delay(14);
digitalWrite(spidata,LOW);
SPI.transfer(array[14]);
SPI.transfer(array[15]);
digitalWrite(spidata,HIGH);
// delay(14);
digitalWrite(spidata,LOW);
SPI.transfer(array[16]);
SPI.transfer(array[17]);
digitalWrite(spidata,HIGH);
delay(1);
digitalWrite(spidata,LOW);
SPI.transfer(array[18]);
SPI.transfer(array[19]);
digitalWrite(spidata,HIGH);
digitalWrite(spidata,LOW);
SPI.transfer(array[20]);
SPI.transfer(array[21]);
digitalWrite(spidata,HIGH);
digitalWrite(spidata,LOW);
SPI.transfer(array[22]);
SPI.transfer(array[23]);
digitalWrite(spidata,HIGH);
// delay(14);
}
Slave receiving data from master then sending the data back to master, is it right.
//Slave receiving data from master and sending back data
#include "pins_arduino.h"
#include <SPI.h>
#define SS 10
int dat[24] = {0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, 0x10, 0x11, 0x12, 0x13, 0x14};
byte c;
void ss_falling()
{
c = 0;
}
void setup (void)
{
// have to send on master in, *slave out*
pinMode(MISO, OUTPUT);
SPI.setBitOrder(MSBFIRST);
SPI.setDataMode (SPI_MODE2);
SPI.setClockDivider(SPI_CLOCK_DIV64) ;
// turn on SPI in slave mode
SPCR |= _BV(SPE);
// turn on interrupts
SPCR |= _BV(SPIE);
// disable timer interrupts
TIMSK0 = 0;
// interrupt for SS falling edge
attachInterrupt (0, ss_falling, FALLING);
// disable timer interrupts
TIMSK0 = 0;
} // end of setup
// SPI interrupt routine
ISR (SPI_STC_vect)
{
c = SPDR;
if(c == 0x04)
{
digitalWrite(SS, LOW);
SPI.transfer(dat[0]);
SPI.transfer(dat[1]);
digitalWrite(SS, HIGH);
digitalWrite(SS, LOW);
SPI.transfer(dat[2]);
SPI.transfer(dat[3]);
digitalWrite(SS, HIGH);
digitalWrite(SS, LOW);
SPI.transfer(dat[4]);
SPI.transfer(dat[5]);
digitalWrite(SS, HIGH);
}
else if(c == 0x06)
{
digitalWrite(SS, LOW);
SPI.transfer(dat[6]);
SPI.transfer(dat[7]);
digitalWrite(SS, HIGH);
digitalWrite(SS, LOW);
SPI.transfer(dat[8]);
SPI.transfer(dat[9]);
digitalWrite(SS, HIGH);
digitalWrite(SS, LOW);
SPI.transfer(dat[10]);
SPI.transfer(dat[11]);
digitalWrite(SS, HIGH);
}
else
SPDR = 0x00; // what to return to the master
} // end of interrupt service routine (ISR) SPI_STC_vect
void loop (void)
{
} // end of loop
TEK0000.BMP (76.1 KB)