【Tutorial】PSRAM版心音取樣器製作小撇步

#include <firFilter.h>

#include <SPI.h>

 

#define PSRAM_CE 10

#define PSRAM_SI 11

#define PSRAM_SO 12

#define PSRAM_SCK 13

 

#define MAX_NUM 1000    // 打算用PSRAM存幾筆，每一筆都有原始和濾波

unsigned long i;

 

#define sensorPin A0      //pin number to use the ADC

int sensorValue = 0;

 

firFilter Filter;  // 低通濾波器

int filtered;       // 被濾波的結果

 

void setup() {

// put your setup code here, to run once:

Serial.begin(115200);

 

// Ready the PSRAM

pinMode(PSRAM_CE, OUTPUT);

SPI.begin();

SPI.setBitOrder(MSBFIRST);

SPI.setDataMode(SPI_MODE0);

SPI.setClockDivider(SPI_CLOCK_DIV2);

 

// Ready FIR low pass filter

Filter.begin();

}

 

void loop() {

// put your main code here, to run repeatedly:

digitalWrite(PSRAM_CE, LOW);  // Enable PSRAM

 

SPI.transfer(0x02); // 命令代碼02表示寫入

SPI.transfer(0);    // Start at 0x000000 in PSRAM

SPI.transfer(0);

SPI.transfer(0);

for(i=0; i<MAX_NUM; i++)  // Sample and filter, store the original and filtered into PSRAM

{

sensorValue = analogRead(sensorPin);    //read the sensor value using ADC

filtered = Filter.run(sensorValue);   // 進行低通濾波，相乘的值由程式庫提供

 

SPI.transfer(sensorValue >> 8);   delay(1);

SPI.transfer(sensorValue & 0xFF); delay(1);

SPI.transfer(filtered >> 8);      delay(1);

SPI.transfer(filtered & 0xFF);    delay(1);

 

delay(1);   // 延遲總時間盡可能接近一半取樣時間，可以自己調整

}

 

digitalWrite(PSRAM_CE, HIGH); // Disable the PSRAM

 

delay(1000);

 

/*

* Now, ready the result back

*/

 

digitalWrite(PSRAM_CE, LOW);  // Enable the PSRAM

 

SPI.transfer(0x03); //Read

SPI.transfer(0);    // Start at 0x000000 in PSRAM

SPI.transfer(0);

SPI.transfer(0);

for(i=0; i<MAX_NUM; i++)

{

sensorValue = SPI.transfer(0);

sensorValue <<= 8;

sensorValue |= (SPI.transfer(0) & 0xFF);

 

filtered = SPI.transfer(0);

filtered <<= 8;

filtered |= (SPI.transfer(0) & 0xFF);

 

Serial.print(sensorValue);

Serial.print(” “);

Serial.println(filtered);

}

 

digitalWrite(PSRAM_CE, HIGH);   // Disable the PSRAM

}