HT1621B Alternatives, Brand, Usage and Other Details
19 March 2024
Ⅲ. Pins and description of HT1621B
Ⅴ. Application circuits of HT1621B
Ⅶ. How to set the display mode of HT1621B?
HT1621B is a high-performance 128 (32X4) mode LCD driver chip produced by Holtek for the analog device market. It is widely used in electronic products such as security monitoring equipment, audio or video equipment, power equipment, and various communication equipment. This article will introduce the HT1621B in terms of brand, pins, usage, etc.
The HT1621B is a memory mapped multi-function LCD driver with 128 (32×4) display segments. Its S/W configuration characteristics make it suitable for a variety of LCD applications, including LCD modules and display subsystems. The connection requirements between the host controller and the HT1621B only require three or four wires. In addition, the HT1621B includes a power-off command to reduce power consumption. The HT1621B is available with S/W configuration for 1/2 or 1/3 bias, as well as configuration of 2, 3 or 4 common LCD drivers. This feature makes the HT1621B suitable for a variety of LCD applications. The built-in time base generator of the HT1621B consists of an 8-stage ripple counter and is designed to generate an accurate time base. On the other hand, its built-in watchdog timer (WDT) consists of an 8-level time base generator and a 2-level count-counter designed to prevent the host controller or other subsystems from abnormal conditions such as unknown or unnecessary jumps, execution errors, etc..
Alternatives and equivalents:
• HK1118
HT1621B is a product of Holtek Semiconductor, which is engaged in the design, development and sales of microcontroller ICs and their peripheral components. Its wide range of products includes general-purpose and specialized microcontrollers that cover a variety of application areas such as touch control, health measurement, industrial control or instrumentation, computer peripherals, home appliances, automotive, and security monitoring. In addition, the company also provides a variety of peripheral components such as power management, LCD/LED driver or control, RF communication chips and various types of sensor modules.
There are four main interface pins of HT1621B, namely CS pin, DATA pin, WR pin and RD pin. If we only perform display operations on the LCD, the RD pin does not need to be considered. The CS pin is used to initialize the serial interface circuit and end the communication between the main controller and the HT1621B. When the CS pin is set to 1, data and commands between the main controller and the HT1621B will be invalid and initialized. Before generating mode commands or performing mode conversion, we need to initialize the serial interface of HT1621B with a high level pulse. The DATA pin is a serial data input or output pin, through which data reading or writing and command writing operations are performed. The RD pin is the read clock input pin. When the RD signal is on the falling edge, data will be output from the DATA pin. Between the rising edge of the RD signal and the next falling edge, the host controller should read the corresponding data. The WR pin is the write clock input pin. When the WR signal is on the rising edge, the data, address and command on the DATA pin will be written to the HT1621B. An optional IRQ pin can be used as an interface between the host controller and the HT1621B. The IRQ pin can be configured as a timer output or WDT overflow flag output through software. When the main controller is connected to the IRQ pin of HT1621B, the time base or WDT function can be implemented.
The following is the basic usage of HT1621B:
1. Wiring: We connect SDA, SCL, VCC and GND of HT1621B to the corresponding pins of the controller respectively. Among them, SDA is the data line and SCL is the clock line.
2. Initialization: By sending commands through the I2C interface, we can perform initialization operations on the HT1621B. This process involves setting the display mode, display brightness, etc. to ensure that it works properly and meets specific display requirements.
3. Write data: By sending data through the I2C interface, we can write the content to be displayed into the HT1621B. In this process, the data plays a crucial role, which contains the ASCII code, Chinese character code and other character information to be displayed.
4. Display content: HT1621B receives the data sent through the I2C interface, it will immediately begin to parse the data. The parsing process is an important part of the HT1621B, which ensures the accuracy and completeness of the data in order to correctly drive the LCD display to show the corresponding content.
5. Control: By sending instructions through the I2C interface, we can precisely control the HT1621B. These instructions cover a variety of control functions, such as setting the display position, switching the display content, etc., which makes the display operation of HT1621B more flexible and diversified.
Host controller with an HT1621 display system
Note:
The connection of IRQ’ and RD’ pin can be selected depending on the requirement of the μC.
The voltage applied to VLCD pin must be lower than VDD.
Adjust VR to fit LCD display, at VDD=5V, VLCD=4V, VR=15kΩ±20 percent.
Adjust R (external pull-high resistance) to fit user time base clock.
1. Low power mode setting
HT1621B has a built-in low-power mode, when the device is not in use, it can automatically enter the power-saving state. By setting the related registers reasonably, we can reduce the power consumption of the device, thus prolonging the service life of the battery.
2. Realization of external expansion function
HT1621B supports the realization of external expansion functions, through the connection with other external devices, more functions can be realized. For example, we can realize real-time temperature display and alarm function by connecting with temperature sensor.
3. Optimization of data transmission rate
When using HT1621B, in order to improve the data transmission rate, we can adopt the parallel transmission method. By connecting multiple HT1621B devices together, we can realize parallel transmission of multiple data, thus significantly improving the transmission efficiency.
4. Error checking and correction
In order to ensure the reliability of data transmission, we can add the function of error checking and correction in the process of data transmission. Specifically, by adding check bits to the data packet and performing the corresponding checksum operation at the receiving end, we can effectively prevent data transmission errors and losses, and ensure the integrity and accuracy of the data.
First of all, we need to have an in-depth understanding of the I2C communication protocol. Given that the HT1621B uses the I2C interface for communication, it is crucial to master its basic principles and operation methods. The I2C interface is mainly composed of a data line (SDA) and a clock line (SCL), and through the cooperative work of these two lines, the master device and the slave device are able to realize an efficient and reliable data transmission between them.
Next, we need to send commands. In order to set the display mode of the HT1621B, we need to send specific instructions to it. For the specific set and format of these commands, we can refer to the product manual or technical documentation of HT1621B. Usually, each instruction will contain an opcode as well as corresponding parameters which are used to explicitly specify the display mode we want to set.
Finally, we need to do the programming work. According to the instruction set of HT1621B, we need to write the corresponding program or code to realize the setting of display mode. This process usually involves sending commands and data to the I2C interface and processing the received data. It is worth noting that the exact programming language and implementation will vary depending on the development platform and programming language used.
Frequently Asked Questions
1. What are some typical voltage requirements for operating HT1621B?
HT1621B typically operates within a voltage range of 2.4V to 5.5V, making it compatible with various power supply configurations commonly used in electronic devices.
2. What kind of applications typically use HT1621B?
HT1621B is commonly used in electronic devices that require LCD display capabilities, such as digital clocks, thermometers, electronic scales, and automotive dashboard displays.
3. What are some advantages of using HT1621B for LCD driving?
Advantages of using HT1621B include its low power consumption, integrated LCD driving capability, compact size, and ease of interfacing with microcontrollers or other control circuits.
