The ula200 Driver

General
The ULA-200 (short for German USB-LCD-Ansteuerung), manufactured and sold by ELV, is a small board that connects a HD44780-compatible display to the computer using the USB interface. Additionally it provides 6 digital inputs that can be used for keys.
The ula200 driver controls this board supporting the features:
display on a single-controller HD44780 display
standard icons (heart, checkbox)
backlight control
input buttons
no horizontal or vertical bars

Requirements
The driver uses libftdi, which again uses libusb for communication with the device, so no kernel driver is needed on Linux, and the driver can be used on other operating systems as well.
When using a libusb based driver like IOWarrior, LCDd needs to be started as root.
On Linux, you have to take care that the ftdi_sio.ko kernel module doesn't claim the ELV device. If you didn't change the IDs in the kernel driver (ftdi_sio.c), this should not matter.

Known problems
Sometimes the display hangs (the ACK response is not received) on shutdown. Reconnect the display in that case. Please do the same if it hangs while starting up. The latter only happens if it was not the first time LCDd talked to the display.

Implementation note

(by the driver's author Bernhard Walle)
The ULA-200 talks a text protocol which allows to display text using a high-level language, i.e. STX s len char0 char1 ... ETX. It also allows low-level register access to the HD44780. So in theory, it would be possible to write a connection type for the hd44780 driver and let the hd44780 core do the rest. I tried this. It was slow and didn't work with user-specific characters (the hd44780 frequently changes this characters which seems to confuse the microcontroller, at least I cannot explain why it didn't work, there was garbage).
So I wrote a separate driver, the ula200, which uses the high-level language and should work for displays with all sizes. I only tested 20x4, so maybe for other sizes the positioning code may be adapted.
As I mentioned, there were problems with frequently changing the user-definable characters. I also tried to implement bar code in the ula200 driver with similar effects. I gave it up because I don't need it personally and it can be done later. However, standard icons are implemented. The user-definable characters are set in startup and are not changed. This works like a charm. It is not possible to use character 0 with the high-level language (or at least it isn't documented how to escape it). It could be done with hd44780 code, but I replaced the character with a standard character which looks good.

Configuration in LCDd.conf

[ula200]
Size = 	 Select the LCD size [default: 20x4]
KeyMap_A = KEY 	 KeyMap_B = KEY 	 KeyMap_C = KEY 	 KeyMap_D = KEY 	 KeyMap_E = KEY 	 KeyMap_F = KEY 	 If you have a non standard keypad you can associate any keystrings to keys. There are 6 input keys in the ULA-200 hardware that generate characters from 'A' to 'F'. Legal values for KEY are Up, Down, Left, Right, Enter and Escape.
The following table lists the built-in default mapping hardcoded in the driver.
KeyMap_A	Up
KeyMap_B	Down
KeyMap_C	Left
KeyMap_D	Right
KeyMap_E	Enter
KeyMap_F	Escape
You may leave it unchanged if you have a standard keypad. You can change it if you want to report other keystrings or have a non-standard keypad.