OK, now re-read reply #4 and explain why you ignored his suggestion.
Respected Sir
Thanks a lot for your kind reply. I have tried with his suggestion also but still I was getting value 0. Please explain me in depth. I am doing something wrong which I am not able to understand. Kindly guide me.
I had used this code also
byte WriteByte (byte value) {
SPDR = value ;
while (!(SPSR & (1<<SPIF)))
{}
return SPDR ;
}
MarkT:
I think your WriteByte routine is failing to complete the process - it reads SPSR but doesn't read SPDR once there's a byte so the hardware never clears ready for the next byte? To quote the datasheet:the SPIF bit is cleared by first reading the SPI Status Register with SPIF set, then accessing the SPI Data Register (SPDR)
How about rewriting WriteByte thus:
byte WriteByte (byte value) {
SPDR = value ;
while (!(SPSR & (1<<SPIF)))
{}
return SPDR ;
}
(So easy to miss a semicolon after a while, use a blank block instead, harder to misread)
Respected Sir
I have used this code also but getting the same value as 0.
Please explain me how to make SPDR to work.
byte WriteByte (byte value) {
SPDR = value ;
while (!(SPSR & (1<<SPIF)))
{}
return SPDR ;
}
byte ReadByte(void) {
while(!(SPSR & (1<<SPIF)))
return SPDR;
}
Do you see a similar problem here?
MarkT said:
(So easy to miss a semicolon after a while, use a blank block instead, harder to misread)
Respected Sir
When I use ; it goes in infinite loop and does not give any output and without ; it gives output as
Output:
Read value
0
Read value
0
Read value
0
Read value
0
Read value
0
Read value
0
Read value
0
Read value
0
Read value
0
Read value
0
Read value
0
Read value
0
Read value
0
Sir ,
Is this code correct, please suggest if something is wrong:
#include <SPI.h>// include the SPI library:
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:
void setup() {
pinMode (spidata, INPUT);// set the spi_data_pin as an output:
SPI.setDataMode(SPI_MODE3);
SPI.setClockDivider(SPI_CLOCK_DIV8);
SPI.begin();// initialize SPI:
Serial.begin(9600);}
byte ReadByte(void) {
while(!(SPSR & (1<<SPIF)));
return SPDR;
}
void loop() {
int rxData;
digitalWrite(spidata,LOW);
rxData = ReadByte();
Serial.println("Read value ");
Serial.println(rxData, DEC);
digitalWrite(spidata,HIGH);
delay(1500);
}
Will you please explain why you are not using SPI.transfer() ?
That's a good point - SPI.transfer will work for both master and slave I think (master mode doesn't require the SPDR to be read, but transfer does this anyway).
There was an almost exact same problem on this thread
http://arduino.cc/forum/index.php/topic,118712.0.html
Same code even.
I still don't know why it didn't work but using SPI.transfer() fixed it.
Rob
Graynomad:
There was an almost exact same problem on this threadhttp://arduino.cc/forum/index.php/topic,118712.0.html
Same code even.
I still don't know why it didn't work but using SPI.transfer() fixed it.
Rob
Dear Sir
Thanks a lot for your kind support.
Can you please provide us the both master and slave codes, it will be great help for me.
Thanks & Regards..
Respected Sir
Thanks a lot for your kind support. Now I am able to receive data form master but after receiving I want to send some data to master back, how can we do this. I have used SPI.transfer() in the master/data-sending code.
Working code.
Sending data code:
#include <SPI.h>// include the SPI library:
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 mm =0;
void setup() {
pinMode (spidata, OUTPUT);// set the spi_data_pin as an output:
SPI.begin();// initialize SPI:
Serial.begin(9600);
}
void loop() {
digitalWrite(spidata,LOW);
SPI.transfer(0x3b); // send in the address and value via SPI:
digitalWrite(spidata,HIGH);// take the SS pin high to de-select the chip:
delay(1500);
}
Receiving data code:
#include <SPI.h>
#include <stdio.h>
#include <avr/io.h>
#include <stdlib.h>
#define MOSI 11
#define MISO 12
#define SCK 13
#define SS 10
int data = 0;
char buff[8];
void setup()
{
pinMode(MOSI, INPUT);
pinMode(MISO, OUTPUT);
pinMode(SCK,INPUT);
pinMode(SS,INPUT);
Serial.begin(9600);
SPCR = 0x40; // Enable SPI in slave mode
// SPI.begin();
delay(500);
}
void loop()
{
Serial.println("Data Received from Master Board");
data = SPI_SlaveReceive();
Serial.println(data, HEX);
data = 0;
}
unsigned char SPI_SlaveReceive()
{
while(!(SPSR & (1<<SPIF)));
return SPDR;
}
Output from receiving code:
Data Received from Master Board
3B
Data Received from Master Board
3B
Data Received from Master Board
3B
Data Received from Master Board
3B
And now what should I do modification in the code so that I can send some data to master once I receive 0x3B from master.
I am trying like this at receiving(slave) side, it is receiving 0x3B from master but not able to send data to master
#include <SPI.h>
#include <stdio.h>
#include <avr/io.h>
#include <stdlib.h>
#define MOSI 11
#define MISO 12
#define SCK 13
#define SS 10
#define sss 9
int data = 0;
char buff[8];
void setup()
{
pinMode(MOSI, INPUT);
pinMode(MISO, OUTPUT);
pinMode(SCK,INPUT);
pinMode(SS,INPUT);
pinMode(sss, OUTPUT);
Serial.begin(9600);
SPCR = 0x40; // Enable SPI in slave mode
// SPI.begin();
delay(500);
}
void loop()
{
int xx;
Serial.println("Data Received from Master Board");
data = SPI_SlaveReceive();
xx = data;
Serial.println(data, HEX);
data = 0;
delay(20);
if(xx == 59)
{
delay(600);
void master_init();
unsigned char send2();
delay(600);
}
}
unsigned char send2(){
digitalWrite(SS, LOW);
WriteByte(16);
digitalWrite(SS, HIGH);
delay(600);}
unsigned char SPI_SlaveReceive()
{
while(!(SPSR & (1<<SPIF)));
return SPDR;
}
void master_init()
{
pinMode(MOSI, OUTPUT);
pinMode(MISO, INPUT);
pinMode(SCK,OUTPUT);
pinMode(SS,OUTPUT);
pinMode(sss, OUTPUT);
}
void WriteByte(byte value) {
SPDR = value;
while (!(SPSR & (1<<SPIF))) ;
return;
}
And at the master side I am doing like this but it is not able to receive the data
#include <SPI.h>// include the SPI library:
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:
#define sss 9
int mm =0;
unsigned char data1 = 0;
void setup() {
pinMode (spidata, OUTPUT);// set the spi_data_pin as an output:
SPI.begin();// initialize SPI:
Serial.begin(9600);
}
void loop() {
//for(mm=0; mm<23;mm++){
digitalWrite(spidata,LOW);
//Serial.println("I am writting on SPI");
//Serial.println(mm, BIN);
SPI.transfer(0x3b); // send in the address and value via SPI:
// SPI.transfer('IMU');
digitalWrite(spidata,HIGH);// take the SS pin high to de-select the chip:
delay(600);
//digitalWrite(sss,LOW);
unsigned char read1();
delay(600);
//digitalWrite(sss,HIGH);
}
unsigned char read1()
{
void slave_init();
data1 = read_ready();
Serial.println(data1, DEC);
data1 = 0;
delay(60);
}
unsigned char read_ready()
{
while(!(SPSR & (1<<SPIF)));
return SPDR;
}
void slave_init()
{
SPCR = 0x40;
pinMode(11, INPUT);
pinMode(12, OUTPUT);
pinMode(13, INPUT);
pinMode(10, INPUT);
delay(600);
}
Kindly suggest me for the modification.
MarkT:
That's a good point - SPI.transfer will work for both master and slave I think (master mode doesn't require the SPDR to be read, but transfer does this anyway).
Dear Sir
Thanks a lot for your kind support. Kindly go through the post Reply #23 on: Today at 05:15:07 PM and please suggest for the modification on the code.
Thanks and Regards.
ranjeetray:
Kindly go through the post Reply #23 ...
Kindly stop ignoring our suggestions.
Dear Sir
Where do you want me to use this SPI.transfer() function in my code, And I am not trying to avoid yours suggestion. Please guide me and help me out.
Thanks & Regards..
Respected Sir,
This code is able to send the data but not able to receive, what is wrong in this;
//send receive
#include <SPI.h>// include the SPI library:
#define SCK_PIN 13
#define MISO_PIN 12
#define MOSI_PIN 11
//#define SS_PIN 10
unsigned char receive_data(void);
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:
unsigned char rd = 0;
void SlaveInit(void) {
// Set MISO output, all others input
pinMode(SCK_PIN, INPUT);
pinMode(MOSI_PIN, OUTPUT);
pinMode(MISO_PIN, INPUT);
pinMode(spidata, INPUT);
Serial.begin(9600);
// Enable SPI
SPCR = B00101100;
SPCR = (1<<SPE);
//SPCR = 0x00;
}
void setup() {
pinMode(SCK_PIN, OUTPUT);
pinMode(MOSI_PIN, INPUT);
pinMode(MISO_PIN, OUTPUT);
pinMode(spidata, OUTPUT);
//pinMode (spidata, OUTPUT);// set the spi_data_pin as an output:
SPI.begin();// initialize SPI:
Serial.begin(9600);
//SPI.setBitOrder(LSBFIRST);
//SPCR = 0x90;
}
void loop() {digitalWrite(spidata,LOW);
SPI.transfer(0x3b); // send in the address and value via SPI:
digitalWrite(spidata,HIGH);
delay(400);
receive_data();
}
unsigned char read_data(void)
{ //SPCR = 0x60;
while(!(SPSR & (1<<SPIF)));
return SPDR; }
unsigned char receive_data(){
pinMode(spidata, INPUT);
SlaveInit();
rd = read_data();
Serial.println(rd, DEC);
rd = 0;
delay(400);
return 0;
}
PaulS:
Even this code is working fine .
Then, what IS your problem?
Respected Sir,
Can we read/transmit here 16 bit data on Arduino board using SPI protocol. Will it generate 16 continuous clock signal.
The Arduino has an 8-bit SPI peripheral and therefore only transmits 8 bits at a time.
However you can just transmit two bytes in a row, the end result is the same.
Rob
Graynomad:
The Arduino has an 8-bit SPI peripheral and therefore only transmits 8 bits at a time.However you can just transmit two bytes in a row, the end result is the same.
Rob
Thanks a lot Sir for your kind reply.
I have done like this only , I am sending SPI.transfer(0x3B); SPI.transfer(0x2C); together in a row, and I am happy that it is transmitting both the data and generating 16 clock cycles on Oscilloscope but Sir, between these two consecutive 8 bit data there is a gap or delay on the Oscilloscope. So, for implementation like IMU(ADIS16405) chip where we need to send 16 bit command, how it will work.
The gap/delay between these two 8 bit data will be considered as 0.
Please suggest something on this.
Thanks & Regards.....
The gap/delay between these two 8 bit data will be considered as 0.
No it won't because the receiving device only clocks in bits on the clock pulses. There is no "clocked" gap.
Thanks a lot Sir, for your kind reply.
Thanks & Regards...