Practical Approach Of Applied Designs Based On AVR

The new architecture microcontroller AVR is introduced in this thesis, both of its CPU core with advanced RISC architecture and of its various bus-compatible peripherals, which are ideally suited for providing a highly flexible and cost effective solution to many embedded control applications. Using its high performance, I provide three different application designs based on AVR in this thesis, In the first Chapter, illustrates the mean ideas of this thesis and gives an overview on AVR. The advantages of the new architecture are introduced in this section, which will tell the necessity of migrating to AVR from MCS51 in new system designs. The application example in Chapter two is a project design that has been used successfully in an automatic checkout system for commercial testing of the front panel module of car DVD/VCD in an electronic factory in Shenzhen. The design is based on ATmega8515, which controls PT6311 via a synchronous serial interface protocol. After studied many different control products, we noticed that even though there are various display screens with different display substances, all of the VFD driver ICs utilize same product: PT6311. PT6311 communicates to MCU via a three-line serial interface with various operation modes. Theoretically, MCU can transmit specific data to make PT6311 activate every display segment of the screen during the testing process by choosing appropriate operation modes. All the segments of the display screen will be turned on, which is the desired testing condition. Compared to the traditional testing methods, our system possesses following features: automation and completeness of the inspection; utilization of one universal platform for different models with same driver/controller IC, significant increase of efficiency and reduction of cost. The development cycle of the testing system is short, and the system is inexpensive to implant, highly efficient, and reliable –fully conform to the initial design requirements. In Chapter three, Atmega88 is in used to control one of the Chipcon's wireless chips CC900. CC900 is a single-chip high performance UHF transceiver from Chipcon, designed for low-power and low-voltage wireless applications. The circuit is mainly intended for the ISM (Industrial, Scientific and Medical) and SRD (Short Range Device) frequency bands at 868 and 915 MHz, but can easily be programmed for operation at other frequency bands in the 800-1000 MHz range. The main operating parameters of CC900 can be programmed via a serial interface, thus making CC900 a very flexible and easy to use transceiver. In a typical system CC900 will be used together with a microcontroller and a few external passive components.Atmega88 is a newest AVR microcontroller from ATMEL, which has a very low power consumption and very high performance. Due to these features, it is very suitable in the wireless applications. The software contains driver routines to do background transmission and receipt of data packages using RF. It also contains a simple function to encode and decode data in the transmission buffer (RAM). The main program contains a simple state machine to handle key entries and allow the user to make future real time applications with increased functionality. The board has a power consumption of less than 1 uA in power down, giving long battery life. The software is written so that the transceiver spends as much time in power down as possible. In polling mode, the MCU wakes up every 200ms, but only wakes up the CC900 each fourth time (approx. once per second). The software waits for a positive edge (start of a '1' in Manchester code), and oversamples two bits. If these bits are good Manchester coded 1's (part of a preamble), the software starts looking for a start-of-frame (SOF), if not, the MCU shuts down the transceiver and goes back to idle mode to conserve battery power. The industry's best combination of key parameters such as low cost, high integration, low power and flexibility, are considered in this design. As such, this design is a work in progress, and will be improved step by step. The expanding spaces for future increasingly needs of new functions are also considered in this design. As a basic wireless application module,the design can be used in many cases after being expanded. The software of the design is simulated passed and works well. The evaluate board both of circuit and firmware is easily to be extended, therefore, allowing designer to make future real time applications interfacing with increased functionality. The basic principles of RF applications are also discussed in this Chapter. In Chapter four, ATmega16 performs as a GPIB Talker to interface to GPIB Bus of the instruments, which provide the GPIB remote function. The control panel of an instrument is easily to be damaged after thousands of handles, and some old instruments cannot be repaired because we can hardly find the fittings today. We know many instruments provide GPIB bus interface for remote controlling, and we can use a device, which can interface the GPIB bus, to control the instruments via GPIB Bus. In this chapter we will focus on the design of the device based on Atmega16. See from the Bus, the device performs as a GPIB Talker, and it also provides a PS/2 keyboard interface for inputting the control commands via a normal PC keyboard. The device based on Atmega16, provides several interfaces for communication. See from the GPIB bus, the device performs as a GPIB talker. My device is designed to interface only one instrument at a time. The device has a PS/2 keyboard interface, and a normal keyboard can work with the device, and the power supply of the keyboard also provided by the device. All control commands supported by the instrument can input via the keyboard. Due to the abundant built-in peripherals of the Atmega16, the device can also provides some other interfaces, which can easily expand the functions for different applications. A RS232 port through a MAX232 chip is connected to the USART of MCU, and the serial communication works at interrupt mode, which is easily for management. An IIC and a SPI interface are optional for the device, which may useful in some cases. The device has characteristics of cost-efficient and high easy-to-use. It can be expanded some new features, for example, it can get GPIB listener function via the software reprogramming. As mentioned at...