"I believe many users who come into contact with the development board for the first time have such doubts. How to choose a development board suitable for themselves? At the same time, I also have a benchmark in my heart and have some expectations: first, this set of development board can not be too outdated. At least there is a wide market application space for some time in the future; Secondly, the price should not be too high, and the performance should be guaranteed. For beginners, it's really difficult to understand these two requirements at the same time. If you have a mentor who is proficient in the development board, you can ask him. If you don't, you might as well take a look at this article, which may bring you some surprises.
The world is advancing rapidly with an unparalleled momentum. Since the advent of 51 single chip microcomputer (MCU) of Intel, the hardware tycoon, the concept of single chip microcomputer is sweeping the world. After rapid development, some famous semiconductor manufacturers such as NXP, Freescale, Renesas, microchip and ATMEL stand out and become the leaders. Today, let's talk about ATMEL's MCU, ATMEL AVR microcontroller.
What is AVR? ATMEL AVR is an 8-bit ~ 32-bit reduced instruction set (RISC) single chip microcomputer based on improved Harvard structure, and it is one of the single chip single chip microcontrollers that use flash memory as data storage medium for the first time. As we all know, there are countless MCU based on ARM kernel. When it comes to MCU, the first idea may be MCU based on arm cortex-x. even if there is no visual fatigue, there will be thought fatigue soon. Therefore, today we will learn about a different development kit based on AVR microcontroller - stk600.
Stk600 development kit features
Aiban.com has evaluated many development boards in different forms, but only from the perspective of packaging, stk600 development kit is really powerful and domineering. In current terms, it is the so-called high-end, atmospheric and high-grade.
However, after opening the packaging, there are not as many boards and accessories as expected. Compared with the packaging box, there is no big surprise
Stk600 evaluation board
ATmega2560 device board
Two I / O ports and 10 core cable programmed in parallel mode
1 6-core cable for online system programming
4. Two core connecting cables with UART and DataFlash
DC power cord
One ATMEL CD-ROM
Two sets of screws and nuts, one set of buckle
It should be noted here that the stk600 evaluation board is the main control board of the whole development kit, and the equipment board is equipped with ATmega2560 by default. However, you can purchase other MCU boards of ATMEL and other AVR series as needed, which can be used compatible. This feature can be said to be the "secret weapon" of stk600. This is also the original intention of aiban.com to promote stk600 and provide a changeable platform for those who first contact the development board.
Make complaints about power line STK600 development kit in addition to the two main board, and bring many different ways of programming cable is also very convenient and practical, but had to Tucao DC power line, without adapter, can only be supplied by digital power, some regrets. Screws, nuts and buckles are made of plastic, which are used to fix the evaluation board and equipment board, which is very convenient and easy to use. As a once valuable ATMEL CD-ROM, in today's network interconnection, it has really become the of "making soy sauce".
Stk600 evaluation board
Speaking of the key points, the stk600 evaluation board is the core control board in this development kit. At first glance, it feels that it has rich functions
There are no devices on the back of the board. The only four copper holes are used to fix the equipment board ATmega2560 through screws, nuts or buckles.
Stk600 evaluation board characteristics
USB power supply, or power supply from external 10-15v DC power supply
AVR device for serial on-line system programming (ISP)
JTAG programmed AVR and AVR32 devices
The external board can be programmed through the AVR device programmed by ISP and JTAG
Flexible expansion of equipment board is convenient to support all kinds of MCU
8 user keys, 8 LEDs
All AVR I / O ports can be connected through the pin seat
Support extended connection plug module and prototype module
DataFlash of onboard 2MB nonvolatile data
USB Mini AB connector
RS232 interface, can bus, LIN bus
Stk600 evaluation board has rich peripheral interfaces and can support 8-bit and 32-bit MCU evaluation and testing of AVR. Next, let's take a closer look at each part of the board.
8 user keys, 8 LEDs and led extension interface (click the picture to enlarge)
Needless to say, user keys and LEDs are basically available on each development board, and the functions are similar. The remarkable feature of stk600 development board is that its expansion interface and the existing logic function interface of the board are independent of each other. For example, two interface sockets, switches and LEDs, are used to lead out the signal interface of user keys and LEDs respectively. In practical use, these two interface sockets must be connected to another signal line interface socket from MCU on the board through 10 core cable, Such as porta, portb, etc. The purpose of this is to allow users to carry out various DIY, increasing the flexibility and variability in the design.
Programming and debugging interface seat (click the picture to enlarge)
The marked expansion interface in the blue area corresponds to the board interface in the green area. The interface in the blue area is connected to the stk600 evaluation board, while the interface corresponding to the Blue interface area in the green area is connected to the interface of the equipment board, and these interfaces are connected through cables to realize the programming and debugging of the equipment expansion board. Of course, the expansion interface in the blue area can also be connected to other development boards. As long as the pin definitions are the same and the interfaces are compatible, you can program and debug other boards.
The jump cap in the blue area is the supply of MCU voltage, reset voltage and analog reference voltage. These voltage values can be modified through ATMEL studio 6.1. The voltage supply range that MCU can set is 0.9 to 5.5V.
Next to the jump cap is a clock switch, which can set the clock mode of MCU on the device board
Ext: programmable clock generator, which can set the frequency from 1.1kHz to 32mhz through ATMEL studio 6.1
XTAL: crystal oscillator on the main board. It is necessary to install 4MHz to 24MHz parallel resonant crystal on the main board, as shown in the figure below
Int: internal RC oscillator of AVR Microcontroller
Reset is the reset button, which is well understood. The program button is used to update MCU firmware. The specific operation method is as follows:
Open ATMEL studio 6.1
Press and hold the program key
Then power on the board and enter the MCU firmware upgrade operation.
Next to the two mechanical keys is the installation place of the crystal of the main control board. It supports the parallel resonant crystal from 4MHz to 24MHz, plug and play, which is very convenient. Next to it is the status LED light of the whole evaluation board, which is green in normal operation. When the board has a problem, the status LED turns red and flashes.
The connecting clamp base between the main control board stk600 and the equipment board needs to be fixed with screws and nuts.
1. ATMEGA16L: 8-bit AVR MCU with built-in 16kb ISP flash
2. Max3390e: 15kV ESD protection, dual / Quad Low voltage level converter
3. Max3392eeud: 15kV ESD protection, dual / Quad Low voltage level converter
4. Mxa4712: 4-way SPST Analog Switch
5. Ti l339: 4-way differential comparator
Equipment board ATmega2560
The device board ATmega2560 can be said to be a replaceable expansion board. The device boards on various stk600 of AVR microcontroller can be found in the official mall of ATMEL, including AVR32 MCU series.
The equipment board of stk600 development kit is mainly MCU The personal show of ATmega2560 has no additional devices except four copper holes echoing with the main control board
MCU is on the back of the equipment board ATmega2560 all pins are compatible with the pin-to-pin interface of the main control board
Power on operation
Before the stk600 development kit is powered on, the main control board and the equipment board must be connected. It feels that the connection with plastic buckle is simpler and easier to use than the combination of screw and nut（ The connection is very simple. I won't repeat it. If I can't, I should think about life: lol:)
I don't know why, after the combination, the more I look at this stk600 development kit, the more pleasing it is. Did the designer study the layout carefully? When everything is ready, plug the cable matching the mini B 4Pin USB interface into the stk600 development board, and turn the power switch to the on position.
At this time, we can see that the power red LED is on. Open ATMEL studio 6.1, enter device programming and select the corresponding settings (as shown below), but an error occurs when reading the device ID.
After careful inspection, it is found that an important point is missing. The programming and debugging interface in the blue area of stk600 board is disconnected from the corresponding debugging interface in the green area on the board. To read ATmega2560, we must connect the corresponding debugging interface. Here, take ISP interface as an example.
ISP with Suite Connect the 6-core cable, and set the next clock switch to the EXT gear, so that the clock frequency can be set through ATMEL studio 6.1. Power on to continue the operation previously interrupted due to an error.
After the stk600 board is set correctly, you can read the MCU device number. You can check the MCU firmware version through the tool information tab. If you don't know whether to update the firmware version, you can check and update the MCU firmware through the program button, but only if your ATMEL studio6.1 is the latest version.
Board setting can set MCU voltage, analog reference voltage 0, analog reference voltage 1 and clock frequency (the clock frequency here is for the clock switch in Ext position)
Device information can view the parameters of MCU ATmega2560. Of course, if you replace different device boards, the information displayed will be different
The memories tab is familiar to you. You can erase, download and other operations of flash through the functions here.
After learning how to set up the stk600 development kit through ATMEL studio 6.1, we might as well run the next program and actually feel the stk600 development kit.
In ATMEL studio6.1, select a routine to control led through GPIO port - GPIO example for the ATmega2560. It can be seen from the introduction that the normal operation of the software requires hardware to connect the portb interface seat with the switches interface seat, and the portd interface seat with the LEDs interface seat.
Compile the code GPIO example for the ATmega2560 and download it to MCU ATmega2560 through ISP.
Oh My God！ LED1 is not on, it's useless to press SW1. Is this a prelude to cheating!!! Is it broken? Use a multimeter to measure and test the quality of the LED.
If you can see a weak light, it means that LED1 is normal. By the way, the connection of LED1 is normal. Well, you can only look back and check the code. Fortunately, the code of ATMEL studio 6.1 is attached with corresponding instructions, so it is easy to find the problem. The original LED1 control signal is not set to high level like other LED control signals, and the LED is turned off. For consistency, it is modified according to other codes, and then recompiled and loaded.
OK, it's finally done. All 8 LEDs have been lit. In addition, the pd0 signal is additionally interrupted in the code, so the lighting or extinguishing of LED0 can be switched through SW0.
This is a simple program for preliminary understanding of AVR microcontroller. In practical application, focus on understanding GPIO port as interrupt processing.
Summary
AVR microcontroller has rich on-chip resources, powerful interfaces and outstanding cost performance. As the preferred MCU in the low-power market, it is widely used in smart home, medical equipment, GPS and other fields. As a learning and development kit for evaluating and testing AVR microcontroller, stk600 has rich functions and huge scalability, which appropriately plays Bole in looking for an ideal AVR microcontroller, The powerful rich functions have to impress the author. Although it is difficult to start stk600 at first, I believe that once I am familiar with the operation of stk600 development kit, everything will become easy. As for the price of stk600, it is still the consistent standard of ATMEL's pricing - $199. It is standard, not cheap or too expensive. Those who are interested can try it. Want to know more about the functions of stk600 development kit? Please pay attention to the follow-up evaluation of aiban.com.
reference material
ATMEL mall
ATmega2560 microcontroller
Stk600 development kit
ATMEL Studio development environment
Original statement: This article is original by Aiban. Reprint is declined“
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