1. The working principle of instruction and data registers
The command register of the assured dot matrix LCD liquid crystal display is used to register the command code, which corresponds to the data of the data register. In the case of D/I=0, the instruction code will be written into IR at the falling edge of E signal. The data register is used to register data and corresponds to the IR register instruction. In the case of D/I=1, the falling edge action graph will display data and write it into DR. Under the action of the E signal high level, the data bus of DB7∽DB0 is read from DR. The data transmission between the DR and DDRAM of the dot matrix LCD liquid display is automatically executed inside the module.
2. The working principle of flags and control triggers
The BF logo of the dot-matrix LCD liquid crystal display can provide the working status of the display. BF=1 means that the module is operated internally, and the system does not accept external commands at this time. BF=0 means the ready state, the system accepts external commands and data at any time. Using related instructions, BF can be read to the DB bus to check whether the module is in a normal working state. The dot matrix LCD liquid crystal display control trigger is used to control the display on and off of the module screen. DFF=1 means the display is on, the content of DDRAM is displayed on the screen, and DFF=0 means the display is off. The state of DDF is controlled by the command DISPLAY ON/OFF and RST signal. The high bit of the counter belongs to the X address, which has no counting function and can only be set by instructions. The low bit belongs to the Y address, and the XY address counter is actually used as the address pointer of the DDRAM.
There are many other useful dot-matrix LCD liquid crystal display related devices, and the address counter is one of them. Although the count value of the counter is not intuitive to the counter of addition and subtraction, it must be calculated by software. The above is the working principle of some important components of the dot matrix LCD liquid crystal display. You can understand the relevant detailed knowledge when purchasing.
