Liquid crystal is a special material state that is different from solid liquid and gaseous state in a certain temperature scale. It has both the birefringence characteristic of anisotropic crystals and the fluidity liquid crystal display device (English) Abbreviated as LCD) is a passive display device that modulates external light by changing the arrangement of liquid crystal molecules of liquid crystal material in an electric field.
LCD12864:
LCD12864 is a graphic dot matrix liquid crystal display, which is mainly composed of row drivers/column drivers and 128&TImes;64 full dot matrix liquid crystal displays. Graphic display can be completed, 8&TImes;4 (16&TImes;16 dot matrix) Chinese characters or 16&TImes;4 (8x16 dot matrix) ASCII codes can also be displayed. There are two types, one with font library and one without font library. LCDs without font libraries need to provide their own fonts. At this time, various font display styles can be set according to personal preference, which is more flexible in design. The LCD with font library provides font library fonts, but it can only display the Times New Roman of GB2312. Each has its own advantages and disadvantages, which can be selected flexibly according to different application scenarios. The schematic diagram of the LCD module is shown below.
Block diagram of LCD12864 dot matrix graphic LCD module
LCD1602
LCD1602 is an industrial character liquid crystal, which can display 16x02 or 32 characters at the same time. LCD1602 liquid crystal display principle The principle of LCD1602 liquid crystal display is to use the physical characteristics of liquid crystals to control its display area by voltage, and display when there is electricity, so that graphics can be displayed.
The lcd1602 liquid crystal display module can only use D4-D7 as the four-bit data to be transmitted in two times. In this way, the I/O port resources of the MCU can be saved. LCD1602 can display 2 lines of 16 characters, 8 data bus DO-D7, and three control ports RS, R/W, EN, working voltage is 5V, and with character contrast adjustment and backlight.
The lcd1602 liquid crystal display module can directly interface with the single-chip AT89C51, the circuit connection is simple, as shown in Figure 1:
The connection of lcd1602 and 51 single chip microcomputer
The difference between LCD1602 and LCD12864:
1. The resolution is different. LCD1602 is a 5*8 dot matrix per word and 16*2 character areas; LCD12864 is a 128*64 resolution dot matrix.
2. The drive chip is also different, so the control word and timing are slightly different
LCD1602 liquid crystal display advantages and disadvantages:
advantage:
1. It is a character type liquid crystal, which is more convenient to display letters and numbers
2. Simple control
3. Lower cost
shortcoming:
1. The displayed font is limited in size
2. Cannot display graphics, etc.
3. It cannot display the curve
The advantages and disadvantages of lcd12864 LCD display:
advantage:
1. Low power consumption
2. Small size does not occupy area
3. Lightweight, ultra-thin, etc.
shortcoming:
1. The LCD12864 liquid crystal display has a large amount of information, so the procedures and circuits are quite complicated.
2. The price is higher
