Hello,
I am making a Master-Slave system with ArduSPi (you can find it here on Github)
Now I made some code for the slave to switch 2 led's. But how can I send the right characters to the slave from the master?
It works with a variable that's need to have a character but how can I do this?
On internet I found some tutorials but they are all with the serial port where the user types the characters and that's not what I want. I just want a demo code to start. Soemthing like this: turn led 1 on, turn led 2 on, turn both led's off.
Here is my code:
Master:
// ArudSPI_master
#define LED_PIN 13
const int slavePause = 50,
nbSlaves = 1,
select = 0,
ack = 1,
slaves[nbSlaves][2] = {{2,3}}//slave O {Select,ack}
// some pretend data to send to the slaves
char dataOut[nbSlaves] = {'R'};
void setup(){
Serial.begin(9600);
for (int i=0;i<nbSlaves;i++){
pinMode(slaves[i][select], OUTPUT);
digitalWrite(slaves[i][select], LOW);
pinMode(slaves[i][ack], INPUT);
}
pinMode(LED_PIN, OUTPUT);
waitForSlaves();
}
void waitForSlaves(){
// pulse LED for 5 seconds before going to the loop.
// this gives time to turn on the slaves,
// it is preferable to turn the slaves on before the master
for(int i=0;i<5;i++){
delay(1000);
pulse(1);
}
}
void loop(){
for (int i=0;i<nbSlaves;i++){
// give visual feedback that we are about to write to a slave
// the number of pulses = 3*SlaveID
pulse(i+1);
writeSlave(i,dataOut[i]);
delay(slavePause);
}
}
void pulse(int c){
// pulse the LED 3 * (arg+1) times
for(int i=0;i<3*c;i++){
digitalWrite(LED_PIN,HIGH);
delay(200);
digitalWrite(LED_PIN,LOW);
delay(200);
}
}
void writeSlave(int id, char data){
// select salve
digitalWrite(slaves[id][select],HIGH);
// send off the data
Serial.write(data);
// wait for the slave to ACK receptions
while(digitalRead(slaves[id][ack]) == LOW){;}
// deselect the slave
digitalWrite(slaves[id][select],LOW);
}
Slave:
// ArduSPI_slave
////////////////////////////////////////////////////////////////////
/// ONLY the following line needs to be changed for each slave !!!!
#define THIS_SLAVE 1
//// end of slave specifics
////////////////////////////////////////////////////////////////////
#define SLAVE_ID THIS_SLAVE
#define SELECT_PIN 2
#define ACK_PIN 3
#define LED_PIN 13
char data;
boolean ledON[2] = {
false};
void setup(){
Serial.begin(9600);
while(!Serial){
;
} // necessary on some Arduinos, may as well keep it.
pinMode(SELECT_PIN, INPUT); // we will read from the 'select' pin
pinMode(ACK_PIN, OUTPUT); // and write to the ACK pin
digitalWrite(ACK_PIN, LOW); // init it to NACK
pinMode(LED_PIN, OUTPUT); // set LED_PIN to writing
digitalWrite(LED_PIN, HIGH);
delay(100);
digitalWrite(LED_PIN, LOW); // and init to' off'
pinMode(5, OUTPUT); // set RED_LED to writing
digitalWrite(5, LOW); // and init to' off'
pinMode(6, OUTPUT); // set BLUE_LED to writing
digitalWrite(6, LOW); // and init to' off'
}
void loop(){
// all we do is get some data and do what it says
// if there is data, do something, otherwise loop
if(getData()){
doSomethingWithData();
}
}
boolean getData(){
// if not selected, ensure ACK_PIN is LOW and do nothing!
if(digitalRead(SELECT_PIN)==LOW){
digitalWrite(ACK_PIN,LOW);
return false;
}
// if we got here, the the SELECT_PIN is HIGH,
// so we need to read serial
// first wait for something to be available to read
while(!Serial.available()){
;
}
// then read 1 byte into the 'data' variable
while(Serial.readBytes(&data,1) == 0) {
;
}
// ACK the serial read
digitalWrite(ACK_PIN,HIGH);
return true;
}
// just to demonstrate that the slave is doing something
// change the LED state at every reception of data.
void doSomethingWithData(){
switch(data){
case 'R':
changeState(5);
break;
case 'B':
changeState(6);
break;
}
}
void changeState(int pin)
{
int x = (pin - 5); // pins starts at 5 and array at 0 so we need to 'convert' it.
ledON[x] = !ledON[x]; // change the state from the boolean variable
if(ledON[x]) // write the change to the corect pin
{
digitalWrite(pin,HIGH);
}
else
{
digitalWrite(pin,LOW);
}
}
regards,
Dylan
