0

我使用以下测试代码来测量使用 Arduino 的 Serial.write() 方法通过 USB 发送单个字节所需的时间。示波器测量到 85 us 发送一个字节。

#include "mbed.h"
#include "nrf_delay.h"
#include "nrf_gpio.h"

#define OUTPUT_PIN NRF_GPIO_PIN_MAP(1,11)

const byte PRINT_BYTE = 254;

uint32_t startClock;
uint32_t stopClock;
uint32_t arithmeticMinuend = 4294967295;
uint32_t arithmeticSubtrahend = 2147483648;
uint32_t arithmeticDifference = 0;
uint32_t timeDifference1 = 0;
uint32_t timeDifference2 = 0;

void setup() {
  delay(1000);
  Serial.begin(115200);
  delay(1000);
  while (!Serial);
  delay(1000);

  nrf_gpio_cfg_output(OUTPUT_PIN);
  us_ticker_init();
  startClock = us_ticker_read();
  stopClock = us_ticker_read();
}

void loop() {
  Serial.println("Starting program:");
  timeDifference1 = microsecondsToSubtract2LongsOnce();
  timeDifference2 = microsecondsToSubtract2LongsAndPrint();
  us_ticker_free();
  Serial.print("timeDifference1 = ");
  Serial.print(timeDifference1);
  Serial.print(" us.\ntimeDifference2 = ");
  Serial.print(timeDifference2);
  Serial.println(" us.");

  us_ticker_init();
  microsecondsToSubtract2LongsOnceMeasuredWithScope();
  us_ticker_free();
  delay(10);
  us_ticker_init();
  microsecondsToSubtract2LongsTwiceMeasuredWithScope();
  us_ticker_free();
  delay(10);
  us_ticker_init();
  microsecondsToToggleOutputPinMeasuredWithScope();
  us_ticker_free();
  
  while(1) {
    
  }
}

//Prints 0-1 us:
uint32_t microsecondsToSubtract2LongsOnce() {
  startClock = us_ticker_read();
  stopClock = us_ticker_read();
  return stopClock - startClock;
}

//Prints 406 us:
uint32_t microsecondsToSubtract2LongsAndPrint() {
  startClock = us_ticker_read();
  Serial.write(PRINT_BYTE);
  stopClock = us_ticker_read();
  return stopClock - startClock;
}

//Measured 1.8 us on scope:
void microsecondsToSubtract2LongsOnceMeasuredWithScope() {
  nrf_gpio_pin_toggle(OUTPUT_PIN);
  startClock = us_ticker_read();
  stopClock = us_ticker_read();
  nrf_gpio_pin_toggle(OUTPUT_PIN);
}

//Measured 85 us on scope:
void microsecondsToSubtract2LongsTwiceMeasuredWithScope() {
  nrf_gpio_pin_toggle(OUTPUT_PIN);
  startClock = us_ticker_read();
  Serial.write(PRINT_BYTE);
  stopClock = us_ticker_read();
  nrf_gpio_pin_toggle(OUTPUT_PIN);
}

//Measured 500 ns on scope:
void microsecondsToToggleOutputPinMeasuredWithScope() {
  nrf_gpio_pin_toggle(OUTPUT_PIN);
  nrf_gpio_pin_toggle(OUTPUT_PIN);
}

我希望能够通过 USB 并行发送所有传感器数据，因此我需要能够比这更快地传输！有人有更好的解决方案吗？

4

1 回答 1

0

为了提高Serial通信的传输速度，您必须增加Serial.begin(). 在这里您可以找到包含波特率和速度的表格。

在您的情况下，波特率 115200 对应于您测量的值的 86us 字节持续时间。

根据 Nordic 的文档，nrf52840 支持波特率直到 1M

于 2022-01-13T19:56:23.137 回答