(1) Memory expansion: Capacity requirements, consider the internal memory resources of the microcontroller when selecting. If it can meet the requirements, it does not need to be extended. Pay attention to the type, capacity and interface of the memory when it is necessary to expand. Generally, leave as much room as possible and reduce the chip as much as possible. Quantity. Choose the appropriate method, ROM and RAM form, RAM to perform power-down protection. (2) Extension of the I/O interface: The MCU application system should consider the volume, price, load capacity, function and other aspects when expanding the I/O interface. The appropriate address decoding method should be selected according to the number of externally extended circuits and the internal resources of the selected microcontroller (the number of free address lines). (3) Design of the input channel: The input channel design includes the design of the switching and analog input channels. The switch quantity should consider the interface form, voltage level, isolation mode, expansion interface, and so on. The design of the analog channel should be combined with the signal detection link (sensor, signal processing circuit, etc.). It should be selected according to the system's requirements for speed, accuracy and price. It also needs to match the performance of the sensor and other devices. Type, type of transmission signal (current or voltage), linearization, compensation, optical isolation, signal processing, etc., should also consider the choice of A / D converter (conversion accuracy, conversion speed, structure, power consumption, etc.) and related Circuits, expansion interfaces, and sometimes software design. High-precision analog-to-digital converters are very expensive, so the requirements for A/D converters should be minimized. The functions that can be implemented in software are implemented in software as much as possible. (4) Design of the output channel: The output channel design includes the design of the switching and analog output channels. The amount of switching should take into account the power and control methods (relays, thyristors, triodes, etc.). The analog output should consider the choice of D/A converter (conversion accuracy, conversion speed, structure, power consumption, etc.), the form of the output signal (current or voltage), isolation mode, expansion interface, and so on. (5) Design of human-machine interface: The design of the human-machine interface includes input keyboard, switch, dial, start/stop operation, reset, display, printing, indication, alarm, and so on. Input keyboard, switch, dial should consider the type, number, parameters and related processing (such as button debounce processing). Start/stop, reset operations should consider the mode (automatic, manual) and its switching. The display should consider the type (LED, LCD), the type of display information, multiples, and so on. In addition, consider the expansion interface of various human-machine interfaces. (6) Design of communication circuit: The MCU application system is often used as a field measurement and control device. It often forms a measurement and control network with the host computer or the co-located machine. It needs the ability of data communication. It is usually designed as RS-232C, RS-485, infrared transceiver and other communication standards. (7) Design and production of printed circuit boards: Circuit schematics and printed circuit board designs are often designed using professional design software such as Protel, OrCAD, etc. Designing a printed circuit board requires a lot of skill and experience. After designing a printed circuit board drawing, it should be sent to a professional manufacturer for production. After installing the components on the printed circuit board, it is completed and produced. (8) Load tolerance considerations: The load capacity of the MCU bus is limited. For example, the load capacity of the P0 port of the MCS-51 is 4 mA, and up to 8 TTL circuits are driven. The load capacity of the P1 to P3 ports is 2 mA, and up to four TTL circuits are driven. If there are more external loads, the bus drive method should be adopted to increase the load tolerance of the system. Commonly used drivers are: unidirectional driver 74LS244, bidirectional driver 74LS245 and so on. (9) Consideration of signal logic level compatibility: In the designed circuit, it is possible to have both TTL and CMOS devices, as well as non-standard signal levels, and to design corresponding level compatibility and conversion circuits. When there are RS-232, RS-485 interfaces, level compatibility and conversion are also required. Commonly used integrated circuits are MAX232, MAX485 and so on. (10) Configuration of the power system: The MCU application system must require a power supply, and the number of power supply groups, output power, and anti-interference should be considered. Be familiar with the application of commonly used three-terminal regulators (78Ñ…Ñ… series, 79Ñ…Ñ… series), precision power supplies (AD580, MC1403, CJ313/336/385, W431). (11) Implementation of anti-interference: Taking necessary anti-interference measures is an important part of ensuring the normal operation of the MCU system. It includes chips, device selection, decoupling filtering, printed circuit board routing, channel isolation, and more. Screen Resolution office projector,projector for office use,projector at office depot,home office projector,hd office projector Shenzhen Happybate Trading Co.,LTD , https://www.happybateprojectors.com
There are generally three screen resolutions for office projectors:
One is a 4:3 screen suitable for office PPT playback. The first is the SVGA machine with the lowest price and the highest cost performance. This kind of machine is generally priced at around 2500 and has powerful performance. The disadvantage is that the resolution is 800X600, which is relatively low. The second is the XGA machine, which is an upgraded version of the SVGA machine with a resolution of 1024X768.
The other is the 16:10 aspect ratio screen used by some foreign-funded enterprises, which is the 1280X800 resolution of WXGA. However, with the transparent price of 1080p projectors, more and more companies will choose full HD 1080p projectors as their office projection solutions.
Office Projector Features
According to the needs of different office environments, office projectors are roughly divided into three categories.
One is a conventional projector that is placed or hoisted in the conference room, the second is a Portable Projector that can be carried around, and the third is an ultra-short-throw projector that is convenient for work reports and speeches.
Wireless Office Projector
With the advent of the Internet era, the emergence of a series of wireless office series has added new members to the office projectors. The wireless office projector is realized by the built-in wireless module of the ordinary office projector. Wireless office makes people do not need to switch signal lines frequently in office meetings, allowing people to have a better experience in meetings!