我有一个运行iOS 5.0.1的越狱Iphone 4，我正试图通过Dock Connector将串行数据发送到我的Arduino。我已成功使用Minicom将数据发送到Arduino，但我似乎无法在应用程序中使用它。这是我的代码，错误在底部。
#include <stdio.h> /* Standard input/output definitions */
#include <string.h> /* String function definitions */
#include <unistd.h> /* UNIX standard function definitions */
#include <fcntl.h> /* File control definitions */
#include <errno.h> /* Error number definitions */
#include <termios.h> /* POSIX terminal control definitions */
#import "ViewController.h"
static struct termios gOriginalTTYAttrs;
static int OpenSerialPort(void);
@implementation ViewController
@synthesize dataLabel, startData;
@synthesize timer;
- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
// Release any cached data, images, etc that aren't in use.
}
#pragma mark - View lifecycle
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
}
- (void)viewDidUnload
{
[super viewDidUnload];
// Release any retained subviews of the main view.
// e.g. self.myOutlet = nil;
}
- (void)viewWillAppear:(BOOL)animated
{
[super viewWillAppear:animated];
}
- (void)viewDidAppear:(BOOL)animated
{
[super viewDidAppear:animated];
}
- (void)viewWillDisappear:(BOOL)animated
{
[super viewWillDisappear:animated];
}
- (void)viewDidDisappear:(BOOL)animated
{
[super viewDidDisappear:animated];
}
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
// Return YES for supported orientations
return (interfaceOrientation != UIInterfaceOrientationPortraitUpsideDown);
}
-(IBAction)startSerial:(id)sender{
timer = [NSTimer scheduledTimerWithTimeInterval:0.1 target:self selector:@selector(targetMethod:) userInfo:nil repeats:YES];
}
static int OpenSerialPort()
{
int fileDescriptor = -1;
int handshake;
struct termios options;
// Open the serial port read/write, with no controlling terminal, and don't wait for a connection.
// The O_NONBLOCK flag also causes subsequent I/O on the device to be non-blocking.
// See open(2) ("man 2 open") for details.
fileDescriptor = open("/dev/tty.iap", O_RDWR | O_NOCTTY | O_NDELAY);
NSLog(@"%d",fileDescriptor);
if (fileDescriptor == -1)
{
printf("Error opening serial port %s - %s(%d).\n",
"/dev/tty.iap", strerror(errno), errno);
goto error;
}
// Note that open() follows POSIX semantics: multiple open() calls to the same file will succeed
// unless the TIOCEXCL ioctl is issued. This will prevent additional opens except by root-owned
// processes.
// See tty(4) ("man 4 tty") and ioctl(2) ("man 2 ioctl") for details.
if (ioctl(fileDescriptor, TIOCEXCL) == -1)
{
printf("Error setting TIOCEXCL on %s - %s(%d).\n",
"/dev/tty.iap", strerror(errno), errno);
goto error;
}
// Now that the device is open, clear the O_NONBLOCK flag so subsequent I/O will block.
// See fcntl(2) ("man 2 fcntl") for details.
if (fcntl(fileDescriptor, F_SETFL, 0) == -1)
{
printf("Error clearing O_NONBLOCK %s - %s(%d).\n",
"/dev/tty.iap", strerror(errno), errno);
goto error;
}
// Get the current options and save them so we can restore the default settings later.
if (tcgetattr(fileDescriptor, &gOriginalTTYAttrs) == -1)
{
printf("Error getting tty attributes %s - %s(%d).\n",
"/dev/tty.iap", strerror(errno), errno);
goto error;
}
// The serial port attributes such as timeouts and baud rate are set by modifying the termios
// structure and then calling tcsetattr() to cause the changes to take effect. Note that the
// changes will not become effective without the tcsetattr() call.
// See tcsetattr(4) ("man 4 tcsetattr") for details.
options = gOriginalTTYAttrs;
// Print the current input and output baud rates.
// See tcsetattr(4) ("man 4 tcsetattr") for details.
printf("Current input baud rate is %d\n", (int) cfgetispeed(&options));
printf("Current output baud rate is %d\n", (int) cfgetospeed(&options));
// Set raw input (non-canonical) mode, with reads blocking until either a single character
// has been received or a one second timeout expires.
// See tcsetattr(4) ("man 4 tcsetattr") and termios(4) ("man 4 termios") for details.
cfmakeraw(&options);
options.c_cc[VMIN] = 1;
options.c_cc[VTIME] = 10;
// The baud rate, word length, and handshake options can be set as follows:
cfsetspeed(&options, B19200); // Set 19200 baud
options.c_cflag |= (CS8); // RTS flow control of input
printf("Input baud rate changed to %d\n", (int) cfgetispeed(&options));
printf("Output baud rate changed to %d\n", (int) cfgetospeed(&options));
// Cause the new options to take effect immediately.
if (tcsetattr(fileDescriptor, TCSANOW, &options) == -1)
{
printf("Error setting tty attributes %s - %s(%d).\n",
"/dev/tty.iap", strerror(errno), errno);
goto error;
}
// Success
return fileDescriptor;
// Failure "/dev/tty.iap"
error:
if (fileDescriptor != -1)
{
close(fileDescriptor);
}
return -1;
}
-(void) targetMethod: (NSTimer *) theTimer {
//dataLabel.text = @"timer running";
int fd;
char somechar[8];
fd=OpenSerialPort(); // Open tty.iap with no hardware control, 8 bit, BLOCKING and at 19200 baud
NSLog(@"%d",fd);
dataLabel.text = [NSString stringWithFormat:@"%d",fd];
if(fd>-1)
{
// dataLabel.text = @"got port";
write(fd,"*",1); // Write handshaking message over serial
///////////////////////////////////////////////////////////////////////////////////////////////////
// After this, our device or our PC program should be strobing serial ground to gain access to the Iphone Serial Line
//////////////////////////////////////////////////////////////////////////////////////////////////
read(fd,&somechar[0],1); // Read 1 byte over serial. This will block (wait) untill the byte has been received
if(somechar[0]=='*') // Check if this byte is a "handshaking" message
{
dataLabel.text = @"handshake accepted";
printf("Serial connection established!\n"); // If it is, we have established a connection to the device and can freely read/write over serial!
while(true) // Do this forever or untill someone presses CTRL+C
{
dataLabel.text = @"in the loop";
read(fd,&somechar[0],1); // Read a character over serial!
dataLabel.text = [NSString stringWithFormat:@"%@",somechar[0]]; // Write the character to the Terminal!!
}
}
}
}
@end
但我得到的错误是：
2012-03-01 19:58:03.507 Iphone-Serial[2470:707] -1
Error opening serial port /dev/tty.iap - Resource busy(16).
我应该重启手机吗？或以某种方式关闭串口？
谢谢， 安德鲁
答案 0 :(得分：1)
您的应用必须具有root权限才能访问tty.iap。只需ssh到您的设备（以root身份），chmod 777 YourApp.app可以解决问题。只需从更简单的代码开始，获得响应并扩展越来越多。