LibFTD2XX

Julia wrapper for the FTDIchip FTD2XX driver.

Installation & Platforms

Install LibFTD2XX using the package manager:

]add LibFTD2XX

Linux driver details

It is likely that the kernel will automatically load VCP drivers when running on linux, which will prevent the D2XX drivers from accessing the device. Follow the guidance in the FTDI Linux driver README to unload the ftdio_sio and usbserial kernel modules before use. These can optionally be blacklisted if appropriate. If your device has an alternate product name you may prefer to use an alternative approach detailed here.

The D2XX drivers use raw USB access through libusb which may not be available to non-root users. A udev file is required to enable access to a specified group. A script to create the appropriate file and user group is available, e.g., here.

Usage

LibFTD2XX provides a high-level wrapper of the underlying library functionality, detailed below. To access the library directly, the submodule Wrapper provides access to the functions detailed in the D2XX Programmer's Guide (FT_000071).

The demonstration considers a port running at 2MBaud which echos what it receives.

Finding and configuring devices

julia> using LibFTD2XX

julia> devices = D2XXDevices()
4-element Array{D2XXDevice,1}:
 D2XXDevice(0, 2, 7, 67330065, 0, "FT3V1RFFA", "USB <-> Serial Converter A", Base.RefValue{FT_HANDLE}(FT_HANDLE(Ptr{Nothing} @0x0000000000000000)))
 D2XXDevice(1, 2, 7, 67330065, 0, "FT3V1RFFB", "USB <-> Serial Converter B", Base.RefValue{FT_HANDLE}(FT_HANDLE(Ptr{Nothing} @0x0000000000000000)))
 D2XXDevice(2, 2, 7, 67330065, 0, "FT3V1RFFC", "USB <-> Serial Converter C", Base.RefValue{FT_HANDLE}(FT_HANDLE(Ptr{Nothing} @0x0000000000000000)))
 D2XXDevice(3, 2, 7, 67330065, 0, "FT3V1RFFD", "USB <-> Serial Converter D", Base.RefValue{FT_HANDLE}(FT_HANDLE(Ptr{Nothing} @0x0000000000000000)))

julia> isopen.(devices)
4-element BitArray{1}:
 false
 false
 false
 false

julia> device = devices[1]
D2XXDevice(0, 2, 7, 67330065, 0, "FT3V1RFFA", "USB <-> Serial Converter A", Base.RefValue{FT_HANDLE}(FT_HANDLE(Ptr{Nothing} @0x0000000000000000)))

julia> open(device)

julia> isopen(device)
true

julia> datacharacteristics(device, wordlength = BITS_8, stopbits = STOP_BITS_1, parity = PARITY_NONE)

julia> baudrate(device,2000000)

julia> timeout_read, timeout_wr = 200, 10; # milliseconds

julia> timeouts(device, timeout_read, timeout_wr)

Basic IO

julia> supertype(typeof(device))
IO

julia> write(device, Vector{UInt8}(codeunits("Hello")))
0x00000005

julia> bytesavailable(device)
0x00000005

julia> String(read(device, 5)) # read 5 bytes
"Hello"

julia> write(device, Vector{UInt8}(codeunits("World")))
0x00000005

julia> String(readavailable(device)) # read all available bytes
"World"

julia> write(device, Vector{UInt8}(codeunits("I will be deleted.")))
0x00000012

julia> bytesavailable(device)
0x00000012

julia> flush(device)

julia> bytesavailable(device)
0x00000000

julia> # Read Timeout behaviour

julia> tread = 1000 * @elapsed read(device, 5000) # nothing to read! Will timeout...
203.20976900000002

julia> timeout_read < 1.5*tread # 1.5*tread to allow for extra compile/run time.
true

Timeouts (only tested on Windows)

julia> buffer = zeros(UInt8, 5000);

julia> twr = 1000 * @elapsed nb = write(device, buffer) # Will timeout before finishing write!
22.997304

julia> timeout_wr < 1.5*twr
true

julia> nb # doesn't correctly report number written
0x00000000

julia> Int(bytesavailable(device))
3584

julia> timeout_wr < 1.5*twr
true

julia> flush(device)

julia> timeout_wr = 1000; # increase write timeout

julia> timeouts(device, timeout_read, timeout_wr)

julia> twr = 1000 * @elapsed nb = write(device, buffer) # Won't timeout before finishing write!
15.960230999999999

julia> nb # correctly reports number written
0x00001388

julia> Int(bytesavailable(device))
5000

julia> timeout_wr < 1.5*twr
false

julia> close(device)

julia> isopen(device)
false