1. Human Interface Devices
EPICS Support

2. What are Human Interface Devices?
Mice
Keyboards
Presentation Remotes
Joysticks
Game Controllers
Barcode Scanners
Card Readers
Variety of other devices

3. Human Interface Devices
Set of interfaces to communicate with a given device
Generally, one interface per capability (Mouse + Keyboard = 2 interfaces)
Interfaces are described by a USB descriptor
You can find this information with the ‘lsusb’ command

6. https://github.com/keenanlang/epics-usb
HID EPICS Support

7. HID EPICS Support
Based on asynPortDriver from asyn EPICS module from Mark Rivers
Descriptor file → asyn parameters
Handles communications with the device in the background. Updates parameters as data changes.

8. Current Uses APS Open House Demonstration
Beamline Motor Control with Wireless Controller

9. HID Driver
Every device will send data over their interfaces on a periodic basis
Just a set of raw bytes
Descriptor file defines how to interpret that data into asyn parameters
Compares new data to old data and only updates changed data

10. Descriptor File One definition per line Example
Parameter_Name [Indicies] -> Parameter_Type
Example
X_AXIS_VALUE [0,1] -> UInt16

11. Descriptor File
Optionally, there are bit shifts and bit masks available for data that doesn’t align to specific bytes.
Name [Index] >> Shift -> Type /0xMask
TEN_BIT_DATA [0,1] -> UInt16 /0x03FF
OFFSET_DATA [1,2] >> 2 -> UInt16 /0x03FF

12. Single-bit True/False
Type Name
Definition
Asyn Type
Int8
8-bit Integer
asynInt32
UInt8
Unsigned 8-bit Integer
Int16
16-bit Integer
UInt16
Unsigned 16-bit Integer
Int32
32-bit Integer
Int8Array
Array of 8-bit Integers
asynInt8Array
Int16Array
Array of 16-bit Integers
asynInt16Array
Int32Array
Array of 32-bit Integers
asynInt32Array
Float64
64-bit Floating Point
asynFloat64
Float32Array
32-Bit Float Array
asynFloat32Array
Float64Array
64-Bit Float Array
asynFloat64Array
UInt32Digital
32-bit Bitmask
Boolean
Single-bit True/False
String
Character Array
asynOctet

13. Driver Functions usbCreateDriver (portName, definitionFile)
Loads the definitions file to create the driver
usbConnectDevice (portName,
interface,
vendorID,
productID,
serial)
Connects the driver to a given device, serial is optional, interface=0 connects to the first available interface
usbShowIO (portName, on_off)
Displays the bytes the device sends every period

14. Driver Functions usbSetFrequency (portName, pollFreq)
Sets the polling frequency of the device for devices that have a constant connection.
Many devices will only send information when an event happens. For those, leave this at 0.0
usbSetTimeout (portName, timeout)
Sets the number of seconds before the device is considered to have timed out. Useful for devices that only send out event data.
UsbSetDelay (portName, delay)
Sets the amount of time between attempting to reconnect to a disconnected device.

15. Example