AVR
microcontroller, compared with the traditional type, in addition to the
IC chip decryption technology must be able to achieve the original some
of the basic features of its architecture, features, performance and
reliability, and many have greatly improved and improved. However,
the device only for the use of better designed and implemented a good
system to create a good foundation and possibility,TPS76333DBVR if it is adopted and
followed the previous tradition of hardware and software design ideas
and methods, then, is not good use of the AVR, even AVR can not really understand the characteristics and strengths. Function better devices, requires higher skills and capabilities of people to use and manage it. IC
chip decryption as a good F1 car, the driver only with superior
technology in order to fully appreciate the car's features, and to
maximize the performance out of the bus. AVR
has started started fast, easy development of simple features, but to
fully appreciate the advantages of the AVR and play, but also require
the application of hardware and software design engineers to develop
their own ability to decrypt the IC chip learning, practice improvement. "Lay
watch the fun, professional and subtle," there is some basis for the
development of embedded and microcontroller system design engineers, may
wish to simply try AVR. Development environment and tools: PC + line + download the actual system board Developing software on the PC: AVR Studio (Free) compile + compiling high-level language debugging debug + + Software Simulation ICC, CVAVR, BASCOM-AVR high-level language program development + download. One
of the purchase of genuine full-featured as the main development
environment, using the DEMO version of other, as auxiliary and
reference. AVR ISP download cable: STK200 and STK200 + and STK300 ISP programmer. PC's
printer port, using ISP technology system operation code (HEX, BIN) and
write data to Flash and EEProm AVR chip, the AVR's configuration fuses
programmed and encrypted bit. Support the overwhelming majority of the AVR chip, compatible chip, and 51 ATMEL 89S8252, 89S52, etc. In the ICC, CVAVR, BASCOM-AVR, BASCOM-8051 are included in the download cable support program. Free download special: SLISP, PonyProg2000 and so on. Try not to use the emulator's recommendations: In
the development and debugging system programs, IC chip decryption,
there are many people totally dependent on the IC chip decryption, once
when he left the simulator feel no start. In
fact, the AVR's Flash memory can be easily repeated using ISP
technology online flash, it is recommended not to use as much as
possible (dependent) to develop and debug emulator program. In the actual development process, debugging is available from several aspects: Now
the high-level language compiler (such as the C compiler) can produce
very efficient machine code, it is recommended that you use an advanced
system programming language. Atmel's AVR Studio using the provided software simulation environment, and other software simulation environment (BASCOM-AVR). Whenever possible, use high-level language system programs. Target board using LED, LCD, or asynchronous serial port. See Annex "There is no case of emulator how to develop AVR" introduction. Improve the hardware design is reasonable: As reasonable as possible and make full use of AVR on-chip resources, such as EEPROM, A / D, the internal RC oscillator. Maximize
the use of peripheral devices connected to serial communication,
large-capacity memory, LCD controller, printer, not 8279 (LED digital
tube + keyboard) and use 7279 and so on. In
addition to foreign expansion RAM (such as voice and video), generally
do not promote the use of parallel expansion (573 + decoding circuit),
reducing hardware and connections and the emergence of the error
probability of the PCB, but also improve the reliability of the system . Parallel Extensions to the serial expansion is the development trend. There are a large number of new high-speed serial peripheral device interfaces such as A / D, D / A, RTC, memory and so on. To make use of the target board and set aside ISP program download interface, or using the IAP technique. Advantages: ISP interface and I / O more compatible than JETAG good. Disadvantages: not online debugging Note that the configuration and control AVR fuse bits to use: Make reasonable use of advanced language writing system design process. Many
people write programs that use the assembly more streamlined and
high-level language development program will waste a lot of space, in
fact, this is a misunderstanding. For
an experienced and very familiar with the compilation of a single-chip
master, he is able to write more streamlined than the high-level
language code. While
the assembly is not very familiar with the developer, or the sudden
replacement of a new chip, you can guarantee will be able to write
high-level language is more concise than the code? Now
the high-level language compiler (such as the C compiler) to generate
the code has been very efficient machine code, it is recommended to
achieve high-level language you can use as much as possible high-level
language programs written in the speed and timing of special occasions
strict can be used to solve the hybrid programming approach. More in-depth and comprehensive grasp of the various serial communication protocol procedures: Embedded
systems are to a large number of peripheral chips use the serial
interface and a variety of communication interfaces such as RS232,
two-wire (I2C), three-wire (SPI), a single bus, USB, CAN, TCP / IP and
so on. Developers
and programmers should be aware of low-level protocol, how familiar and
how to achieve lower hardware protocol, how to define the upper and
reliable application protocol, as well as with low-level protocol driver
interface between the upper layer application protocol design (the
middle layer software implementation), etc. Hardware
engineers, software development, the ability to improve, using standard
programming methods, improving the overall framework of software
design, good data structure and program structure system. (Computer
software professional programmers are not familiar with the hardware,
mostly under the aegis of the operating system software, interface and
protocol for low-level driver layer and the interface does not
understand, often not a good SCM system written procedures.) Communication interface should be prepared as much as possible . Using interrupt + buffer, . Hierarchical + structure design, As far as possible not to use Round Robin (to reduce the efficiency of the AVR). See URAT (RS232) driver + middle-tier software examples. The use of good system design: Try
not to use the traditional front and back (break) system design,
interaction and interference between the tasks, not timed operation. Such as the design of a dynamic scan mode to drive the 8-bit LED digital display + dynamic scan 4 * 4 matrix keyboard. State machine design using TimeTip + + CASE structure, multi-tasking operating system design. Or time-triggered system design. (See: "time-triggered embedded system design," China Electric Power Press, 2004.6) Transplant small embedded operating systems, such as UCOS-II. Some free online simple AVR-based operating system. Improve the C language programming skills and software application level: Familiar and good use of C data structures, pointers application, memory management and other more advanced applications. Knowledge and understanding of your development platform using high-level language features. The
platform for a class of processors, including many special extension is
not compatible with the structure of the statement and, statements,
functions and so on. Although easy to use, but because of its opacity and the uncertainty of the time, and therefore fair use. Such as C's getchar (), putchar () and so on. AVR has multiple development platforms, each has its own characteristics and weaknesses. To the integrated use of these platforms complement each other, can improve development efficiency. Such
as through the ICC, CVAVR program generator CodeWizard learn and
understand the AVR hardware setup, simplify the calculation, the program
quickly generate the basic modules, such as "a URAT (RS232) + lower
middle layer software driver examples."
