How to make an array to send the data to slave in AVR - c

Question

I'm working on an AVR to learn it. my code is working properly. mean it gave me the output same as I want but I want to modify the code. I made 4 functions to send the data to the slave. like as it's in the code I want to send 61,62,63,64. but for these, I make four functions. Now I want to modify it as all the data send to the salve by one function. so my line of code will be reduced. second I want that once the 61 sends to the salve it prints something like datatransfered and once the dataexchange it's display **exchanged**. I tried to make the array and take numbers one by one but was unlucky.
#include <xc.h>
#include <avr/io.h>
#include <avr/interrupt.h>
#include <stdio.h>
void SPI0_init(void);
void LTCSelect(void);
void LTCDeselect(void);
uint8_t SPI0_exchangeData(uint8_t data);
uint8_t SPI1_exchangeData(uint8_t data1);
uint8_t SPI2_exchangeData(uint8_t data2);
uint8_t SPI3_exchangeData(uint8_t data3);
void SPI0_init(void){
PORTA.DIR |= PIN4_bm; /* Set MOSI pin direction to output (output to LTC2983) */
PORTA.DIR &= ~PIN5_bm; /* Set MISO pin direction to input (input form LTC2983) */
PORTA.DIR |= PIN6_bm; /* Set SCK pin direction to output (output to LTC2983) */
PORTA.DIR |= PIN7_bm; /* Set CS pin direction to output (output to LTC2983) */
SPI0.CTRLA = SPI_CLK2X_bm /* Enable double-speed */
| SPI_DORD_bm /* LSB is transmitted first */
| SPI_ENABLE_bm /* Enable module */
| SPI_MASTER_bm /* SPI module in Master mode */
| SPI_PRESC_DIV16_gc; /* System Clock divided by 16 */}
uint8_t SPI0_exchangeData(uint8_t data){
SPI0.DATA = data;
while (!(SPI0.INTFLAGS & SPI_IF_bm)) /* waits until data is exchanged*/
{
}
return SPI0.DATA;}
uint8_t SPI1_exchangeData(uint8_t data1)
{
SPI0.DATA = data1;
while (!(SPI0.INTFLAGS & SPI_IF_bm)) /* waits until data is exchanged*/
{
}
return SPI0.DATA;}
uint8_t SPI2_exchangeData(uint8_t data2){
SPI0.DATA = data2;
while (!(SPI0.INTFLAGS & SPI_IF_bm)) /* waits until data is exchanged*/
{
}
return SPI0.DATA;}
uint8_t SPI3_exchangeData(uint8_t data3){
SPI0.DATA = data3;
while (!(SPI0.INTFLAGS & SPI_IF_bm)) /* waits until data is exchanged*/
{
}
return SPI0.DATA;}
void LTCSelect(void){
PORTA.OUT &= ~PIN7_bm; // Set SS pin value to LOW}
void LTCDeselect(void){
PORTA.OUT |= PIN7_bm; // Set SS pin value to HIGH}
int main(void){
uint8_t data = 61;
uint8_t data1 = 62;
uint8_t data2 = 63;
uint8_t data3 = 64;
SPI0_init();
while(1){
LTCSelect();
SPI0_exchangeData(data);
SPI1_exchangeData(data1);
SPI2_exchangeData(data2);
SPI3_exchangeData(data3);
LTCDeselect();
}}

Answer 1

Just use the first function. The others are just a copy, are the same and unnecessary.
uint8_t SPI0_exchangeData(uint8_t data){
SPI0.DATA = data;
while (!(SPI0.INTFLAGS & SPI_IF_bm)) /* waits until data is exchanged*/
{
}
return SPI0.DATA;
}
and in your main loop call the same function to send all your data:
int main(void){
uint8_t data = 61;
uint8_t data1 = 62;
uint8_t data2 = 63;
uint8_t data3 = 64;
SPI0_init();
while(1){
LTCSelect();
SPI0_exchangeData(data);
SPI0_exchangeData(data1);
SPI0_exchangeData(data2);
SPI0_exchangeData(data3);
LTCDeselect();
}
}
There you shuld have your numbers respectively in your slave device.
Update for sending array
/**
* Sends an uint8_t array to SPI0
*
* Here we send an array of uint8_t (aka unsigned char) to SPI0 one by one.
* using the length parameter and an index variable.
*
* #param data a data array to send to SPI0.
* #param length the length of the given array.
* #returns nothing, but you can return any util info if you wish
*/
void sendArray(uint8_t data[], uint8_t length) {
for(uint8_t i = 0; i < length; i++) {
SPI0_exchangeData(data[i]);
}
}
// Suppose we have an array named buffer
uint8_t buffer[] = { 10, 20, 30, 40, 50, 60, 70, 80, 90, 100 };
// Some where in the main loop we want to send it to the SPI0
int main(void) {
//...
while(1) {
//...
// We pass the array and its length in this way
sendArray(buffer, sizeof(buffer));
}
return 0;
}
Note that the array is defined and assigned statically. In real cases the arrays mostly used with a statically allocated memory, say 64 bytes i.e. uint8_t buffer[64];, but this does not mean that it will contain data in full capacity. Hence when the data is written to an array must be counted and stored in a variable to know the actual length of that array when needed.