SimVimCockpit has direct support (since v.0.9.17) of commonly used character LCDs with 4-bit parallel interface, such as 1602/1604/4002 (+ 20x2, 20x4 can be supported). No libraries are used, SimVim firmaware controls the LCD directly.
All standard ASCII Characters and a some of custom symbols can be used to display information on LCDs. Using online SimVim configurator you can easily assign any data to be displayed:
You need to use only 5 signal lines and GND connected to the data bus and one signal line connected to the output pin assigned for this particular display. Four address/data lines S0,S1,S2,S3 should be connected to 4 data inputs of every LCD - D4,D5,D6,D7. The "D" signal of the bus is connected to the "RS" (register select) input of the LCD.
These displays consume very little power from the power source, so you can use +5v from the same SimVim bus. To be able to see something on the screen, you need to add contrast control to the input (V0) using a small potentiometer / trimpot (resistance can be from 1K to 10K Ohm) connected between +5V and GND:
On the other side of the LCD there are two inputs for the backlight LED ( +A - anode, -K - cathode). The "K" input connected to the common GND, and "A" - to the "+" of the power source, which can also be an additional power supply.
Although the backlight LEDs can consume quite much power, you can still connect the A input to the bus +5V instead of an external source. This is especially viable if you use a powerful source for +5v line in your system bus, not taken from the controller board +5 output. Use an additional resistor (50 - 100 Ohm) on the A input in this case.
All parameters that can be assigned to 7-segment displays can also be assigned to LCDs to display values. In addition, you can display text by selecting the "Display_Text" parameter from SimVim Functions, or by selecting any annunciator-type parameter and choosing the type "LCD conditional text". As with any input or output, any parameter assigned to an LCD can also be tied to conditions.
In most cases, you will want to assign multiple parameters to the same LCD. To add any parameter after you've already assigned one, select the same pin after choosing a parameter and click "Append".
The option that is always available is the position of the output on screen - the line number and the position in the line.
In case of parameter value output, you also need to specify the maximum length in characters that this value can occupy.
A text field is always available for LCD outputs. In case of value output, it is optional text placed before or after the value. In the other cases, the text is the only thing that is displayed.
If you want a certain LCD output to be displayed only when a certain condition is met, you can assign this condition, and then select the "Link to conditions" checkbox when adding an LCD output, which will allow you to configure the conditions for it.
Selecting "LCD conditional text" for annunciator-type parameters is an easier way to assign conditionally displayed text to LCD, without the need assign conditions separately.