I have a USB device attached. I decided to try to write some code where I open the USB device as a FileDescriptor like on Linux where I can use ioctl function on the fd to send commands.
I ended up with the following:
CFMutableDictionaryRef matches = IOServiceMatching(kIOUSBDeviceClassName);
if (!matches)
{
std::cerr<<human_error_string(kIOReturnError)<<"\n";
return;
}
io_iterator_t deviceIterator;
kern_return_t kr = IOServiceGetMatchingServices(kIOMasterPortDefault, matches, &deviceIterator);
if (kr != kIOReturnSuccess)
{
std::cerr<<human_error_string(kr)<<"\n";
return;
}
io_service_t service = IO_OBJECT_NULL;
while((service = IOIteratorNext(deviceIterator)))
{
int32_t fd = IOServiceOpenAsFileDescriptor(service, O_RDWR) //doesn't work! Returns: -1
IOObjectRelease(service);
}
IOObjectRelease(deviceIterator);
However, the FD is always -1.. Any ideas why?
As far as I'm aware, there isn't any kind of file descriptor based API for USB on macOS. You need to go through the IOUSB based APIs. There's some example code here.
If you want to share as much code as possible between Linux an macOS, you can use libusb which wraps both Apple's IOKit API and Linux's ioctl based USB API.
I have to admit I'm not exactly sure what IOServiceOpenAsFileDescriptor is intended for. The source code in IOKitLib is not terribly enlightening, as it simply connects to an XPC service and the file descriptor is expected in the XPC reply. I assume the service is implemented in a system daemon that isn't open source or documented.
Perhaps IOServiceOpenAsFileDescriptor is for accessing block devices or serial ports, which have both an IOKit object and a device node file in /dev/. General USB devices do not have a node in the file system.
I'm currently creating a program that's divided in two parts, one where I detect nearby bluetooth devices and connect them to the pc if the name match and the other where I search for the device with setupapi and get an handle for HID comunication.
My problem is that I cannot find anything that tells me that the device I just connected is the same I found in setupapi.
So in the first part I have something like this:
BLUETOOTH_DEVICE_INFO btdi;
//--- Code omitted ---
BluetoothGetDeviceInfo(radio_handle, &btdi);
if(std::wstring(btdi.szName) == /*my name*/)
// Device found! now connect
BluetoothSetServiceState(radio_handle, &btdi, &HumanInterfaceDeviceServiceClass_UUID, BLUETOOTH_SERVICE_ENABLE);
And the setupapi related code:
SP_DEVICE_INTERFACE_DATA device_data;
device_data.cbSize = sizeof(SP_DEVICE_INTERFACE_DATA);
//--- Code omitted ---
SetupDiEnumDeviceInterfaces(device_infos, NULL, &hid_guid, index, &device_data);
I was thinking about using the bluetooth address of the device but there seem to be no way to get that from setupapi.
So, to recap, is there any way to get the address of the device from setupi? And, if not, is there any other way to be sure that they're both the same device?
Here I posted the code how to find Wiimote connected as HID using its MAC. You have to rework that code so it can use your HID device (change VID and PID).
I have a Linux system with multiple USB flash drives plugged in, as /dev/sda1, /dev/sdb1, etc. I need to eject one of these from within my program -- something like EjectDrive("/dev/sdb1"); I then may need to programmatically re-insert the drive.
I know I can do this from the command line if I know the USB bus, port and device number. e.g. echo '2-1.3' > /sys/bus/usb/drivers/usb/unbind and then echo '2-1.3' > /sys/bus/usb/drivers/usb/bind
I'm not sure how to do this from C++, and be 100% sure I am using the correct bus, port and device for the specified drive.
This is an embedded platform with BusyBox v1.22.1, so udev is not available to me, and lsusb returns minimal information.
Yes it can be done using libusb (follow this link for libusb usage with C++). Now a few things to keep in mind -
1 - What is the device address? (You can get this using libusb API)
libusb_get_device_list (libusb_context *ctx, libusb_device ***list)
libusb_get_device_address (libusb_device *dev)
libusb_get_port_number (libusb_device *dev)
2 - Is the device connected to the root hub port or to a hub port? (This can be done by reading the parent device of the /dev/sdb1 or sda1)
libusb_get_parent (libusb_device *dev)
3 - If its connected to a hub, then do a control transfer to "clear" PORT_POWER feature of that port. That will turn off the port and the device will be disconnected. You can "set" PORT_POWER feature to turn on the port and the device will be connected again. Remember that you will not get any disconnect event which is as per the spec. (EHCI or XHCI)
int libusb_control_transfer ( libusb_device_handle * dev_handle,
uint8_t bmRequestType,
uint8_t bRequest,
uint16_t wValue,
uint16_t wIndex,
unsigned char * data,
uint16_t wLength,
unsigned int timeout
)
4 - If the device is connected to the root hub port directly, then please check if libusb supports clearing root hub port power. I am not sure about this. This also depends on the Host controller driver stack.
Please follow the link I mentioned at the top for example usage of these API's.
I'd like to access the Structure Sensor (https://structure.io) via OpenNI 2 (https://github.com/occipital/openni2) from an UWP App running on a Windows 10 Desktop.
The Setup
For this very reason I created a Windows Runtime Component (Universal Windows) in C++ besides my actual UWP App. This component exports several functions basically miming the initialization behavior of one of the samples in above OpenNI Github repo.
I extended the code to also iterate through all available devices:
// Initialize OpenNI
Status rc = OpenNI::initialize();
if (rc != STATUS_OK)
{
logError("Initialize failed + " + std::string(OpenNI::getExtendedError()));
return false;
}
// Get all attached sensors supported by OpenNI
Array<DeviceInfo> deviceList;
OpenNI::enumerateDevices(&deviceList);
for (int i = 0; i < deviceList.getSize(); i++) {
logInfo(deviceList[i].getName());
logInfo(deviceList[i].getUri());
}
// Actual open device
Device device;
rc = device.open(deviceList[0].getUri());
if (rc != STATUS_OK)
{
logError("Error = " + to_string(rc));
logError("Couldn't open device " + std::string(OpenNI::getExtendedError()));
return false;
}
The Problem
Calling above code from my UWP app through the Windows Runtime Component is successful when initializing OpenNI and enumerating over all available devices:
[INFO] PS1080
[INFO] \\?\usb#vid_1d27&pid_0600#13261#{c3b5f022-5a42-1980-1909-ea72095601b1}
Actually Opening the device via device.open is the actual problem (Error 1 = STATUS_ERROR)
[ERROR] Error = 1
[ERROR] Couldn't open device Could not open "\\?\usb#vid_1d27&pid_0600#13261#{c3b5f022-5a42-1980-1909-ea72095601b1}": USB device not found!
I'm also under the impression that above error message is a bit misleading, as the actual message when having no device attached is:
[ERROR] Error = 1
[ERROR] Couldn't open device DeviceOpen using default: no devices found
I already tried to add a USB device capability to the package mainifest without any success.
<DeviceCapability Name="usb">
<Device Id="vidpid:1D27 0600">
<!--<Function Type="classId:ff * *" />-->
<Function Type="name:vendorSpecific"/>
</Device>
</DeviceCapability>
I also verified that above code is working when directly building a classic C++ program without targeting UWP at all.
I would be very happy for any direction/hint you can provide me with
The Solution
Microsoft's UWP policy simply doesn't allow access to USB devices. But you can workaround that by grant the UWP AppContainer Process access to the Structure IO sensor.
Some manual work is required though:
Open the registry editor and go to the USB entry of the Structure IO sensor HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Enum\USB\VID_1D27&PID_0600
Uncollapse this node and right click on the node below this one and copy the whole key in to clipboard. The last digit is very important here and differs from machine to machine (e.g. HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Enum\USB\VID_1D27&PID_0600\13261)
Copy this key into following registry file where the brackets are. The following registry modification basically allows every UWP app access to the structure I/O sensor.
Windows Registry Editor Version 5.00
[HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Enum\USB\VID_1D27&PID_0600\13261]
"Security"=hex:1,0,4,90,0,0,0,0,0,0,0,0,0,0,0,0,14,0,0,0,2,0,60,0,4,0,0,0,0,0,14,0,0,0,0,10,1,1,0,0,0,0,0,5,12,0,0,0,0,0,18,0,0,0,0,10,1,2,0,0,0,0,0,5,20,0,0,0,20,2,0,0,0,0,14,0,0,0,0,10,1,1,0,0,0,0,0,5,B,0,0,0,0,0,18,0,0,0,0,10,1,2,0,0,0,0,0,F,2,0,0,0,1,0,0,0
Modify the following batch script to point to the full path(!) of above registry file. This script is needed to modify the registry with the security string. This is only allowed by Window's SYSTEM account. That's why we need to create a task for that.
call schtasks /create /RU SYSTEM /SC ONCE /TN DeviceAC /TR "reg import c:\full\path\to\registry\file.reg" /ST 00:00
call schtasks /run /tn DeviceAC
call schtasks /delete /tn DeviceAC /f
Run the above batch script with Administrator privileges
After successfully executing the script, make sure there's a new entry called "Security" below you node from 2.
If the sensor is already connected to your PC you'll need to reconnect it.
Now the code from my Question above should work :)
You'll find a detailed read on how to solve this problem here:
https://developer.microsoft.com/en-us/windows/iot/Samples/CustomDeviceAccessor
I need to interface an old machine (thermostream) to interface with the raspberry pi (model B+)
The thermostream device has a RS232 serial port and I want to connect it to the USB port of the raspberry pi using the RS232 serial to usb cable (where the usb end of the cable is inserted in the pi and the serial end is connected to the device). And I need to write the code in python.
IS this possible? If yes, how should I proceed? Any help is greatly appreciated.
Yes. First you need to install pyserial
Then, in Python, you can use the following function to create a serial object that connects to a port. The usb ports on the pi are dynamically assigned a name and those names can change. This function will enable you to loop through each port for the name. (might not work well with multiple devices attached). Check your connection settings on the device you wish to communicate with (baudrate, parity, stopbits etc) and modify the code to use those settings.
import serial
def serialConnect():
serlocations=['/dev/ttyACM', '/dev/ttyACM0', '/dev/ttyACM1','/dev/ttyACM2', '/dev/ttyACM3','/dev/ttyACM4', '/dev/ttyACM5','/dev/ttyUSB0','/dev/ttyUSB1','/dev/ttyUSB2','/dev/ttyUSB3', '/dev/ttyUSB4', '/dev/ttyUSB5', '/dev/ttyUSB6', '/dev/ttyUSB7', '/dev/ttyUSB8', '/dev/ttyUSB9', '/dev/ttyUSB10','/dev/ttyS0', '/dev/ttyS1', '/dev/ttyS2', 'com2', 'com3', 'com4', 'com5', 'com6', 'com7', 'com8', 'com9', 'com10', 'com11', 'com12', 'com13', 'com14', 'com15', 'com16', 'com17', 'com18', 'com19', 'com20', 'com21', 'com1', 'end']
for device in serlocations:
try:
ser = serial.Serial(
port=device,
baudrate=9600,
parity=serial.PARITY_ODD,
stopbits=serial.STOPBITS_TWO,
bytesize=serial.SEVENBITS
)
print device
return ser
except:
x=0
if device == 'end':
print "No Device Found"
ser = serialConnect()
if ser:
ser.write("TEST")
ser.timeout=5
for i in ser.readlines():
print i