This driver supports the serial and USB interface alphanumeric display modules by Crystalfontz.
The USB versions simply use an USB-to-serial called FTDI_SIO (not pl2303), and use the same protocol as on the serial port. So you just have to change the Port entry in the config file to get them to work.
The driver fully supports the text, bar and icon widgets.
All the cool features of the newer displays (GPO's, PWM outputs, temperature and fan speed measurement, …) are supported by the driver.
Display Section
Display <name> {
Driver 'Crystalfontz'
Model <string>
Port <string>
Speed <number>
Contrast <number>
Backlight <number>
Icons <number>
}
Parameters
| Driver | 'Crystalfontz' |
| Model | see below |
| Port | serial device the display is attached to (e.g.'/dev/ttyS2') |
| Speed | the baud rate from the display must match this value. Possible values are 1200, 2400, 4800, 9600, 19200, 38400 and 115200 |
| Contrast | initial contrast value, 0..255 (range depends on the display) |
| Backlight | initial backlight brightness, 0..100 |
| Icons | Number of user-defined chars reserved for Icons (default: 0) |
Models
The driver supports various different Crystalfontz displays, which can be selected with the Model parameter:
| Model | Size | Protocol |
| 626 | 2×16 | |
| 631 | 2×20 | |
| 632 | 2×16 | |
| 633 | 2×16 | |
| 634 | 4×20 | |
| 635 | 4×20 | |
| 636 | 2×16 |
Displays with the old protocol 1 are serial displays only. The newer ones (2 and 3) come with serial and USB interfaces. They support display autodetection, you can try to omit the 'Model' parameter.
If you get a blank display when running LCD4Linux, play around with Contrast an Backlight values. Some users reported that using Contrast 85 and Backlight 30 works very good…
Examples
Display CF631 {
Driver 'Crystalfontz'
Model '631'
# Recent versions of 2.4 and 2.6 kernels use '/dev/ttyUSB0'
Port '/dev/tts/USB0'
Speed 115200
# Range from 0-255. Datasheet suggests 90 as 'about right'
Contrast 90
# Range from 0 = off, 1-99 = variable, 100 = Full on.
Backlight 100
Icons 1
}
Display CF632 {
Driver 'Crystalfontz'
Model '632'
Port '/dev/tts/0'
Speed 19200
Icons 2
}
Display CF633 {
Driver 'Crystalfontz'
Model '633'
Port '/dev/tts/0'
Speed 19200
Contrast 16
Backlight 50
Icons 4
}
Display CF635 {
Driver 'Crystalfontz'
Model '635'
# This is using linux kernel 2.6.x and the future tech serial->usb driver
Port '/dev/ttyUSB0'
Speed 115200
# Use some sane values here for backlight vs contrast.
# too little contrast with not enough backlight won't show anything
# 20 is simply a value I chose during testing, and one that you don't have to use.
Contrast 85
Backlight 20
Size '20x4'
Icons 8
}
Plugins
The driver provides the following functions (depends on the display model):
| LCD::contrast() | return current contrast setting |
| LCD::contrast(n) | set contrast to n (0..255, range depends on the display) |
| LCD::backlight() | return current backlight setting |
| LCD::backlight(n) | set set backlight off (0) or on with brightness (1..100) |
| LCD::fan_pwm(n) | return value of fan PWM output number n (1..4) |
| LCD::fan_pwm(n, v) | set fan PWM output n (1..4) to value v (0..100) |
Fixme: other cool features (fan rpm measurement, temperature measurement are currently not implemented!
—-
Keypad
As of Feb. 2006 CVS, keypad on the 635 is supported.