早上好！最近，我买了一个Arduino开发板来对房间进行“灯光控制”。这是我编写的固件代码：

int control = 0;
int pin = 0;

void setup()
{
  Serial.begin(9600);
  for(pin = 0; pin <= 13; pin++) pinMode(pin, OUTPUT);
}

void loop()
{
  control = Serial.read();
  if (control > 0 && control <= 13) digitalWrite(control, HIGH);
  if (control < 256 && control >= (256-13)) digitalWrite((256-control), LOW);
}

之后，我使用了Python解释器中的pySerial来控制引脚，一切工作正常。这是一段解释器输出：

Python 2.6.5 (r265:79063, Apr 16 2010, 13:57:41) 
[GCC 4.4.3] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import serial
>>> ser = serial.Serial('/dev/ttyUSB0', 9600)
>>> ser.write(chr(12))
>>> # The light turned on here
... 
>>> ser.write(chr(256-12))
>>> # The light turned off here
...

然后，我决定编写一个简单的Python脚本来执行相同的操作：

#!/usr/bin/env python

import serial
import time

ser = serial.Serial('/dev/ttyUSB0', 9600)

ser.write(chr(12))
time.sleep(1)
ser.write(chr(256-12))

但这根本不起作用！Arduino显示在我启动脚本的过程中收到了一些东西，但是什么也没发生。这是脚本的strace输出：

open("/dev/ttyUSB0", O_RDWR|O_NOCTTY|O_NONBLOCK) = 3
ioctl(3, SNDCTL_TMR_TIMEBASE or TCGETS, {B9600 -opost -isig -icanon -echo ...}) = 0
ioctl(3, SNDCTL_TMR_TIMEBASE or TCGETS, {B9600 -opost -isig -icanon -echo ...}) = 0
ioctl(3, SNDCTL_TMR_TIMEBASE or TCGETS, {B9600 -opost -isig -icanon -echo ...}) = 0
ioctl(3, SNDCTL_TMR_START or TCSETS, {B9600 -opost -isig -icanon -echo ...}) = 0
ioctl(3, SNDCTL_TMR_TIMEBASE or TCGETS, {B9600 -opost -isig -icanon -echo ...}) = 0
open("/dev/ttyUSB0", O_RDWR|O_NOCTTY|O_NONBLOCK) = 4
ioctl(4, SNDCTL_TMR_TIMEBASE or TCGETS, {B9600 -opost -isig -icanon -echo ...}) = 0
ioctl(4, SNDCTL_TMR_TIMEBASE or TCGETS, {B9600 -opost -isig -icanon -echo ...}) = 0
ioctl(4, SNDCTL_TMR_TIMEBASE or TCGETS, {B9600 -opost -isig -icanon -echo ...}) = 0
ioctl(4, SNDCTL_TMR_START or TCSETS, {B9600 -opost -isig -icanon -echo ...}) = 0
ioctl(4, SNDCTL_TMR_TIMEBASE or TCGETS, {B9600 -opost -isig -icanon -echo ...}) = 0
write(4, "\f", 1)                       = 1
close(4)                                = 0
rt_sigaction(SIGINT, {SIG_DFL, [], SA_RESTORER, 0x7f45cf4c88f0}, {0x4d9820, [], SA_RESTORER, 0x7f45cf4c88f0}, 8) = 0
exit_group(0)                           = ?

看起来一切都应该很好，所以我不知道问题可能出在哪里。我将不胜感激，在此先感谢您！

PS当我在PDB下运行该程序时，一切正常。Heisenbug。

更新：我让控制器将接收到的数据发回给我，并且在运行脚本时似乎什么也没接收到，但是当我从解释器发送数据时，接收到了所有内容。固件的代码现在如下所示：

int control = 0;
int pin = 0;

void setup()
{
  Serial.begin(9600);
  for(pin = 0; pin <= 13; pin++) pinMode(pin, OUTPUT);
}

void loop()
{
  if (Serial.available() > 0)
  {
    control = Serial.read();
    if (control <= 13) digitalWrite(control, HIGH);
    if (control < 256 && control >= (256-13)) digitalWrite((256-control), LOW);
    Serial.println(control);
  }
}