DISPLAYS
LCD PANELS
I am testing two types of displays in my ALDL instrument. LCD panels are relatively cheap and easy to use. In automotive applications main problem LCD’s is poor temperature range. Most displays start to slow down below +5 to +10 degrees and become not usable around freezing point. Storage temperature spec is usually between –10 and –20 degrees Celsius. If you go below display breaks down. Good thing is very good contrast also in bright sunlight. Also easily adjustable LED back light panels are available.
VFD DISPLAYS
Vacuum Fluorescent Displays have excellent temperature characteristic usually –20 to +70 C. Problems are poor contrast in bright environment especially in direct sunlight you can see nothing. In automotive applications another problem is limited brightness control.
Most of LCD panels are done with Hitachi HD44780 controller. Hitachi
HD44780 datasheet gives good interfacing and how to write your I/O information.In my prototypes I have used following displays.
2 x 20 scrap LCD panels
4 x 20 Batron very small LCD Possible plan is to replace e.g. Voltmeter and put this display instead. TCM gives also accurate battery voltage reading. I have used BT42003.
4 x 20 Noritake-Itron VFD panel this use the same interface as LCD panels.
