Question

我正在尝试从FPGA到Arduino实现自己的SPI通信，其中我的FPGA充当MASTER并生成芯片使能和通信时钟。 FPGA在其上升沿发送数据，并在其下降沿接收数据，我的FPGA代码正常工作。

在Arduino端，我在中断时捕获该主时钟，并在其上升沿接收数据并在其下降沿发送，但如果我将时钟速度从10 KHz提高，则通信无法正常工作。

根据我的理解，Arduino Due工作在84 MHz，处理1 MHz中断不是一个大问题。你能告诉我如何用Arduino Due来处理这个高速时钟吗？

下面的Arduino代码：

void ISR1();
// this constant won't change
const int  S_CLK = 19; //  slow clock in this case FPGA is master
const int  MOSI_C =  51; //   Master out slave in in this case arduino
//receive data from FPGA
const int  MISO_C = 50; //  Master in slave out in this case arduino
//transmit data from FPGA
const int  SS_C = 53; // the pin that the pushbutton is attached to
const int TRANS_INDEX = 32; //index that is used to transmit data in this
cas 32 bits are transmitted
const int REC_INDEX = 48;

#define CLK_MAIN    84000000UL

//Variables will change

int ss_check = 0; //used for reading of slave select
int mosi_data[REC_INDEX + 2]; //delcare receiving data array length
int count = 0; //used for convertion of bits to bytes
int index_r_stat = 0; //give us a value of status that
how much bits are received
int flag = 0; //used for stop reading s
int miso_out[TRANS_INDEX] = {
  1, 0, 1, 0, 1, 0, 1, 1, 1, 0, 1, 1, 0, 1, 0, 0, 1, 1, 1, 0, 0, 0, 1, 0, 1, 1, 0, 1, 1, 0, 1, 0
};
int miso_index = 0; //used for above array
int last_clk_state = 1; //used for the detection of rising and
falling edge

int check_clk;
void setup() {
  //   initialize the button pin as a input
  pinMode(S_CLK , INPUT);
  pinMode(MOSI_C , INPUT);
  pinMode(MISO_C , OUTPUT);
  pinMode(SS_C , INPUT);
  //   initialize serial communication
  Serial.begin(9600);
}

void loop() {
  //   read the pushbutton input pin
  ss_check = digitalRead(SS_C);
  //Serial.println(ss_check);
  //WAIT until slave select is not read
  if (ss_check == 0) {
    //attach interrupt so that data is
    attachInterrupt(digitalPinToInterrupt(S_CLK), ISR1, CHANGE);
  }
  if ((index_r_stat == (REC_INDEX + 1)) && (flag == 0)) {
    for (int i = 1; i < (REC_INDEX + 1); i = i + 1) {
      Serial.print(mosi_data[i]);
      flag = 1;
      if (count < 7) {
        count = count + 1;
      } else {
        count = 0;
        Serial.println();
      }
    }
  }
}

void ISR1() {
  if ((last_clk_state == 1) && (digitalRead(S_CLK) == 0)) {
    check_clk = 0;
    //this code is used to transmit data to FPGA
    if (miso_index < TRANS_INDEX - 1) {
      digitalWrite(MISO_C, miso_out[miso_index]);
      miso_index = miso_index + 1;
    } else {
      miso_index = miso_index;
    }
  } else {
    check_clk = 1;
    //this code is used for reading data from FPGA
    if (index_r_stat < (REC_INDEX + 1)) {
      mosi_data[index_r_stat] = digitalRead( MOSI_C);
      index_r_stat = index_r_stat + 1;
    } else {
      detachInterrupt(S_CLK);
      index_r_stat = index_r_stat;
    }
  }
  last_clk_state = digitalRead(S_CLK);
}

Arduino到期最大中断频率

0 个答案: