Pushing old good numeric LCD to the limits

In most cases we use these HD44780 LCDs for displaying text messages. But also there are four bytes in LCD RAM that can store custom characters. This is handy when we need special symbol to be displayed. But here is a good example how text LCD can be turned in to graphical display and be used to chow pretty neat graphics. Program library is written in PicBASIC and runs on PIC16F628A. Library works in similar way as you would write code for graphical display. You can set point coordinates, draw a line or circle. Library takes care of updating custom chars when needed and refresh LCD. As you can see refresh rate is impressive. Playing with refresh and pixel ON times there is also a doubled resolution mode. Continue reading

The Cute Little Smart Library – Contre-Bargraph!

If you having a job that always require you printing all those company’s bargraph all day long, then you must be very interested about this Contre-Bargraph gadget! For your information, this cute little smart library will allow you to generate up to 8 special characters for the HD44780 compatible alphanumeric LCDs, then you can use them to print the bargraph whatever you want. Basically, the idea is to use 8 special characters to create pseudo-graphics on an alphanumeric matrix 16X2 LCD. The pseudo-graphics you’re about to generate here represent a 16-char bargraph, which it is originally used in a simple boring project that involving temperature measurement and PIC16F877. By the way, you need to have a LCD driver to provide the main LCD functions, because the bargraph code only uses the ‘set cgram address’ and ‘write’ commands. This LCD lib uses delay functions that should be provided somewhere by your compiler or toolchain as an example or a lib. Also, please remember that the driver itself has to use chip-specific functions, where it’s the least portable part here. Lastly, most… Continue reading