#include <SPI.h>
#include "Arduino.h"
#include <string.h>
#define FIRSTCHANNEL 15
const int chipSelectPin = 10;
volatile int16_t channel_data[10000] = {0};
//int8_t recieve_data[20000];
volatile int8_t buff[20000] = {0};
void setup() {
  // put your setup code here, to run once:
  SPI.begin(); //Initialize SPI bus
  unsigned int timecnt;
  pinMode(chipSelectPin, OUTPUT); //Set the chipSelectPin to be an output on the Arduino
  
  Serial.begin(9600); //Initialize the serial monitor to monitor at 9600 Baud
  SPI.beginTransaction(SPISettings(8000000, MSBFIRST, SPI_MODE0)); //Set Arduino's SPI settings to match those of the RHD2000 chip - max clock speed of 8 MHz, data transmitted most-significant-bit first, and mode 0: clock polarity = 0, clock edge = 1
  delay(250); 


  
  timecnt = micros();
  for(int i=0;i<10000;i++){
    channel_data[1] = SendConvertCommand(FIRSTCHANNEL);
  }
  timecnt = micros() - timecnt;
  Serial.print("round-robin timecnt= ");
  Serial.print(timecnt/1000);  // 27ms ~8MHz
  Serial.println("ms");
  delay(250);


  
  timecnt = micros();
  SPI.transfer(&buff ,sizeof(buff));
  timecnt = micros() - timecnt;
  Serial.print("one calling timecnt= ");
  Serial.print(timecnt/1000);  // 21ms ~8MHz
  Serial.println("ms");
 
}

void loop() {
  // put your main code here, to run repeatedly:

}

uint16_t SendConvertCommand(uint8_t channelnum) {
  //Sends a CONVERT command to the RHD chip through the SPI interface
  //The channelnum is the channel number that is desired to be converted. When a channel is specified, the amplifier and on-chip ADC send the digital data back through the SPI interface
  uint16_t mask = channelnum << 8;
  mask = 0b0000000000000000 | mask;
  //digitalWrite(chipSelectPin, LOW);
  uint16_t out = SPI.transfer16(mask);
  //digitalWrite(chipSelectPin, HIGH);
  return out;
}