Drive the performance characteristic of the chip HTl621 and make up the structure, combine and fly to think of Karl’s little controller MC9S08AW32 according to the liquid crystal, have described the design of a kind of electrical home appliances liquid crystal display system. Have described HT1621 practical application in the display system design of this liquid crystal in detail, have explained hardware forming and software design process of this system especially, and provide interface block diagram of the hardware and software flow diagram. The display system of this liquid crystal reveals steadily, fine performance such as low power dissipation, the interface friendship, and saved little controller I/O port resources.
The display system of the liquid crystal is the important component of the control system of electrical home appliances. The liquid crystal display system of electrical home appliances reveals the module Liquid Crys-tal Display through the liquid crystal Show important information such as its working state and time out, users assign the operation order to deal with to the little controller according to the information, thus realize the control on function of the electrical home appliances. The liquid crystal reveals the module not merely can reveal figure, Chinese character and character vividly, and the consumption is little, the working voltage is low, so the application in the modern electrical home appliances products is more and more extensive. The intersection of electrical home appliances and the intersection of liquid crystal and display system including liquid crystal reveals the module LCD mainly, backlight source, liquid crystal drive the chip HT1621, flies and thinks of Karl’s little controller MC9S08AW32 and button module etc.. Here, according to the performance characteristic, making up structure and programming method, combine MC9S08AW32 of HT1621, have described HT1621 practical application in the liquid crystal display system of electrical home appliances in detail, have explained hardware design and software design process of this system, and provide hardware interface block diagram and software flow diagram of this system.
A liquid crystal drives the chip HT1621 introduction
1. Characteristic of 1 HT1621
HTl621 is held group HOLTEK in Taiwan 128 sections which the company puts out 32* 4The multi-functional driver of the built-in memory, can drive the multistage LCD character to be its main characteristic. HTl621 can form LCD and reveal module and display system, only needs 3- 4 with the communication of little controller, it also included at the same time the electricity orders in a province, reduced the systematic consumption effectively. SSOP that HTl621 is 48 pins encapsulates, has a lot of fine characteristics, its main characteristic is as follows:
1.Working voltage 2. 4- 5. 2 V;
2.Inlay 256 kHz RC oscillator inside;
3.The order can be used in reducing the consumption economizing on electricity;
4.A LCD driver of 32* 4 sections;
5.32* 4 that inlay in one reveal RAM memory;
6.Mode of three kinds of access to data.
1. Systematic structure within 2 HT1621
The systematic structure includes revealing the memory RAM within HT1621 Systematic oscillator, guard the gate the intersection of dog and timer, the intersection of voice and generator and the intersection of LCD and driver,etc.. Only introduce the display memory correlated to this design RAM as follows With LCD driver.
1. 2. 1 reveals the memory RAM
The static behavior reveals the memory RAM, store the data revealed in the form of 32* 4. The data of RAM can shine upon the driver to LCD; The data stored in RAM can use READ, WRITE and READ-MODIFY-WRITE order to visit. Fig. 1 is the image from RAM to LCD driver.
1. 2. 2 LCD driver
HT1621 is one and 128 sections 32* 4LCD driver. It can dispose from software into LCD driver biasing and 2, 3 or 4 public ports of 1/ 2 or 1/ 3. This characteristic makes HT1621 suitable for many kinds of LcD to employ the occasion. LCD drives the clock to be produced from the frequency division of the systematic clock; LcD drives the frequency value of the clock to keep as 256 Hz, it is 32 by the frequency. The shaking brilliantly of 768 kHz, Rc oscillator or external clock in slice are produced; See Table 1 in relevant order of LcD driver.
Runic 100 is ” 100″ Express the order mode type. If carry out the continuous order, except the first order, mode type of other orders yard will be neglected. LCDOFF orders to make LCD bias the generator and fail, thus close LCD to reveal; LCD ON orders to make LCD bias the generator effectively, thus opened LCD to reveal.
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