SlaveSPIClass_esp32_Arduino

SlaveSPIClass.cpp

#include<SlaveSPIClass.h>
 int SlaveSPI::size = 0;
 SlaveSPI** SlaveSPI::SlaveSPIVector = NULL;
void setupIntr(spi_slave_transaction_t * trans)
{
	for(int i=0 ; i<SlaveSPI::size;i++)
	{
		if(SlaveSPI::SlaveSPIVector[i]->match(trans))
				SlaveSPI::SlaveSPIVector[i]->setup_intr(trans);
	}
}
void transIntr(spi_slave_transaction_t * trans)
{
	for(int i=0 ; i<SlaveSPI::size;i++)
	{
		if(SlaveSPI::SlaveSPIVector[i]->match(trans))
				SlaveSPI::SlaveSPIVector[i]->trans_intr(trans);
	}
}
SlaveSPI::SlaveSPI()
{
	SlaveSPI** temp = new SlaveSPI * [size+1];
	for (int i=0;i<size;i++)
	{
		temp[i]=SlaveSPIVector[i];
	}
	temp[size] = this;
	size++;
	delete [] SlaveSPIVector;
	SlaveSPIVector = temp;
	buff = "";
	transBuffer = "";
}
void SlaveSPI::begin(gpio_num_t so,gpio_num_t si,gpio_num_t sclk,gpio_num_t ss,size_t length,void(* ext)())
{
	
	
	//should set to the minimum transaction length
	t_size = length;
	
	driver = new spi_slave_transaction_t{t_size * 8 ,	0 ,	heap_caps_malloc(max(t_size,32), MALLOC_CAP_DMA),	heap_caps_malloc(max(t_size,32), MALLOC_CAP_DMA),NULL};
	
	spi_bus_config_t buscfg={
        .mosi_io_num=si,
        .miso_io_num=so,
        .sclk_io_num=sclk
    };
	
    gpio_set_pull_mode(sclk, GPIO_PULLUP_ONLY);
    gpio_set_pull_mode(ss, GPIO_PULLUP_ONLY);
	spi_slave_interface_config_t slvcfg={ss,0,1,0,setupIntr,transIntr};//check the IDF for further explenation
	
	spi_slave_initialize(HSPI_HOST, &buscfg, &slvcfg,1); //DMA channel 1
    
	spi_slave_queue_trans(HSPI_HOST,driver,portMAX_DELAY);//ready for input (no transmit)
	
	exter_intr =ext;
}

void SlaveSPI::setup_intr(spi_slave_transaction_t *trans)
{//called when the trans is set in the queue
	//didn't find use for it in the end.
}
void SlaveSPI::trans_intr(spi_slave_transaction_t *trans)
{//called when the trans has finished

	for(int i=0;i<t_size;i++)
	{
		buff += ((char*)driver->rx_buffer)[i];
		((char*) driver->rx_buffer)[i] = (char)0;
	}
	setDriver();
	exter_intr();
}
void SlaveSPI::trans_queue(String& transmission){
	//used to queue data to transmit
for (int i=0;i<transmission.length();i++)
		transBuffer += transmission[i];
}
inline bool SlaveSPI::match(spi_slave_transaction_t * trans)
{
	return (this->driver == trans);
}
void SlaveSPI::setDriver()
{
	driver->user = NULL;
	int i=0;
	for(;i<t_size&&i<transBuffer.length();i++)
	{
		((char*) driver->tx_buffer)[i] = transBuffer[i];
		
	}
	transBuffer = &(transBuffer[i]);
	driver->length=t_size*8;
	driver->trans_len = 0;
	spi_slave_queue_trans(HSPI_HOST,driver,portMAX_DELAY);
}
char SlaveSPI::read()
{
	char temp = buff[0];
	buff.remove(0,1);
	return temp;
}

SlaveSPIClass.h

#ifndef SLAVE_SPI_CLASS
#define SLAVE_SPI_CLASS
#include "Arduino.h"
#include "driver/spi_slave.h"
void setupIntr(spi_slave_transaction_t * trans);
void transIntr(spi_slave_transaction_t * trans);
class SlaveSPI
{
	static SlaveSPI** SlaveSPIVector;
	static int size;
	friend void setupIntr(spi_slave_transaction_t * trans);
	friend void transIntr(spi_slave_transaction_t * trans);
	String buff;//used to save incoming data
	String transBuffer;//used to buffer outgoing data !not tested!
	spi_slave_transaction_t * driver;
	void (*exter_intr)();//interrupt at the end of transmission , if u need to do something at the end of each transmission
	size_t t_size;//length of transaction buffer, (should be set to maximum transition size)
	
	public:
	SlaveSPI();
	void setup_intr(spi_slave_transaction_t *trans);//called when the trans is set in the queue
	void trans_intr(spi_slave_transaction_t *trans);//called when the trans has finished
	
	void begin(gpio_num_t so,gpio_num_t si,gpio_num_t sclk,gpio_num_t ss,size_t length=128,void(* ext)() = NULL);
	void trans_queue(String& transmission);//used to queue data to transmit 
	inline char* operator[](int i){return (&buff[i]);}
	inline void flush(){buff = "";}
	inline bool match(spi_slave_transaction_t * trans);
	void setDriver();
	char read();
	inline String* getBuff(){return &buff;}

};

#endif

SlaveSPITEST.ino

#include <SlaveSPIClass.h>
#include <SPI.h>
#define MO 22
#define MI 23
#define MCLK 19
#define MS 18
#define SO 32
#define SI 25
#define SCLK 27
#define SS 34
SlaveSPI slave;
SPIClass master(VSPI);
void test();
void setup() {
  Serial.begin(115200);
  // put your setup code here, to run once:
master.begin(MCLK,MI,MO);
slave.begin((gpio_num_t)SO,(gpio_num_t)SI,(gpio_num_t)SCLK,(gpio_num_t)SS,8,test);//seems to work with groups of 4 bytes
SPI.beginTransaction(SPISettings(14000000, MSBFIRST, SPI_MODE0));
pinMode(MS,OUTPUT);
}
String txt = "";
String cmd ="";
void loop() {
  // put your main code here, to run repeatedly:
if(slave.getBuff()->length()&&digitalRead(SS)==HIGH)
{
  while(slave.getBuff()->length())
    txt+=slave.read();
  Serial.println("slave input:");
  Serial.println(txt);
}
while(Serial.available())
{
 cmd +=(char) Serial.read();
}
while(txt.length()>0)
{
  slave.trans_queue(txt);
  Serial.println("slave output:");
  Serial.println(txt);
  txt ="";
}
while(cmd.length()>0)
{
  Serial.println("input:");
  Serial.println(cmd);
  Serial.println("Master input:");
  digitalWrite(MS,LOW);
  for(int i=0;i<cmd.length();i++)
  {
    cmd[i] = master.transfer(cmd[i]); //ERROR : gives the transmitted data <<1 
  }
  digitalWrite(MS,HIGH);
  for(int i=0;i<cmd.length();i++)
    Serial.print(cmd[i],HEX);
  cmd ="";
}
}
void test()
{
  //Serial.println("test");
  //Serial.println(slave[0]);
}