"Recently, when I saw the product promotion of microchip, I couldn't help thinking of a previously purchased pickit3 debug express development tool. Because I haven't had much time, I haven't had much trouble. I'll take it out for fun and give you a reference.
Almost all friends who play single chip microcomputer know pic Series MCU, which is the main series product of American microchip. Microchip is a leading single chip microcomputer and analog semiconductor supplier in the world, especially known for the stability and reliability of PIC single chip microcomputer, which is used more in the field of industrial control. The set of pickit debug express development tool in the author's hand includes a pic8 Series MCU demonstration board (see the figure below).
PICkit3 Debug Express
The complete set of pickit3 debug express development tools mainly includes:
Pickit3 online debugging / Programmer
A 44pin demonstration board based on pic8 Series MCU
A pickit3 use document, a mini USB cable and a CD (including MPLAB ide development tools and 12 sample courses)
Nowadays, the network is popular. Ide development tools and development board routines can be found on the Internet. Therefore, few development board products still carry CD-ROM. from this point, we can see that pickit3 has some history. To get back to business, let's take a closer look at these products.
Pickit3 debug express development kit
Microchip's pickit3 online debugger is relatively small, with a red ordinary plastic shell. It also retains a hanging rope buckle in industrial design, which is very considerate. Friends who often lose things can take advantage of it. However, according to people's current aesthetic level, it is estimated that no one will hang it around their neck.
Pickit3 online programming debugger
Pickit3 online debugger looks like a lot of content, but in actual use, only one function key can be operated. The function of this function key is one of the main features of pickit3 - offline burning.
Offline writing is also compared with online writing (writing by connecting to a computer). Friends who do not know this function may just have no contact with it. This is a very practical function in production or mass production. It eliminates the connection with a computer and can be used in large quantities. However, pickit3 is not suitable for mass production, The specific reason is that pickit3 does not support incremental ID burning, which is inconsistent with the factory specifications of actual mass-produced products (generally, products need a unique ID number before leaving the factory). However, this function is very convenient in the product development process. In addition to the function keys on pickit3, the status of each LED is also noteworthy in the burning process. The specific functions will be introduced in use.
The plastic shell of pickit3 debugger is not tightly sealed. On the contrary, it is easy to disassemble. I believe you will be curious about the internal composition of pickit3 debugger. Let's have a look.
Pickit3 debugger PCB
The PCB board of pickit3 debugger looks very simple. It supplies power through the Mini USB interface, while the main chip PIC24 series microcontroller supplies power through the LDO output of 3.3V. The PCB board carries two EEPROM, one for storing the debugger's own information file and the other for storing the burning code program, that is, in the offline burning mode, First burn the compiled code program into EEPROM for storage, and then disconnect the computer and directly use pickit3 debugger to burn other target boards. Its interface adopts ICSP debugging interface, which is defined as shown in the figure below.
ICSP debugging interface definition
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The microcontroller of pickit3 debugger is a 16 bit MCU pic24fj256gb106 based on Harvard architecture of microchip company, with USB2.0 OTG function. It supports 16mhz main frequency at most, integrates 256Kb flash, 16kb ram, 4 UARTS, 3 SPIs, 3 I2C, 1 16 bit ADC, 3 comparators and other peripheral functions (see the figure below).
Pickit3 debugger main control chip pic24fj256gb106
Pic24fj256gb106 system block diagram
After finishing pickit3 debugger, let's take a look at its demo demo board.
Demo demo board
Compared with the pickit3 debugger, the demo demo board has less content. The visible functions are only 10K adjustable variable resistance, 8 LEDs and 1 programming connector interface. In addition, it only leads out all the pins of the pic18f45k20 microcontroller, which is convenient for friends who like DIY.
Pic18f45k20 is an 8-bit microcontroller of microchip. It also adopts Harvard architecture, 16mhz dominant frequency, integrates 32K flash, 1.5kb ram, 256b data EEPROM, a 13 channel 10 bit ADC, 2 comparators, 1 UART, 1 I2C, 1 SPI and other peripheral functions. See the pic18f45k20 system block diagram below for details.
Compared with today's microcontroller, the peripheral function of 8-bit MCU pic18f45k20 is very concise, but it is suitable as a demonstration board. Get familiar with the hardware of pickit3 debug express development kit inside and outside, and then we'll officially use it.
Use of pickit3 debug express development kit
The pickit3 debugger must be used in conjunction with the IDE development tool of microchip (at present, there are mainly two IDE software versions of MPLAB and MPLAB x, which will be introduced below). Because the CD comes with MPLAB v8.60, we will use this ide software first.
Install the MPLAB ide v8.60 tool from the CD-ROM. after installation, the interface is very simple, which is far from the current ide design tool interface. Fortunately, it is very smooth. Let's run a routine and click Project - > open to load the routine in the CD-ROM. the author takes blink LED as an example.
Open the routine file on the CD
Blink LED assembly source code
It's still an assembly language. It's amazing. The author compiles several times and reports errors. The software even doesn't respond. It prompts that the correct compilation tool is not selected. At this time, it may be caused by not selecting the correct execution path or not installing the compiler for pic8 bit MCU, For a far fetched solution, you can download the 8-bit compiler installation for PIC series on the official website of microchip. Although it is only a 60 day trial version, it is better for free. Of course, you can also buy the standard version or professional version. The compilation speed is faster and more efficient, but the price is very expensive.
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After downloading and installing the compiler, select the correct compiler tool to compile successfully, and then download directly. First, power on the pickit3 debugger and there will be a prompt for new firmware update.
Update firmware of pickit3 debugger
After updating the firmware, connect the demo board to the pickit3 debugger, and pay attention to the first step sequence when connecting. In the previous introduction, we know that the additional power supply interface of the target board has not been led out, and the online programming and debugging of pickit3 debugger is based on the power on of the target board. At present, the board can be powered through the pickit3 debugger through the MPLAB ide software settings, as shown in the following figure.
Set the power supply to demo board through pickit debugger
The selection range of this voltage is 1.8V ~ 3.6V. Because the power supply port is directly connected to the voltage of the microcontroller on the demonstration board, you can refer to the working voltage of the microcontroller. If it is too small, the chip will be damaged and cannot work. Through the test, it is found that the actual output voltage will be slightly less than the software setting, which may be related to the software algorithm and voltage drop, Therefore, it is advisable to set a slightly larger voltage in practical use.
After the output voltage is set, the demo demonstration board can be identified and the ID number of the demonstration board can be read. After the demonstration board is powered on, the built-in water lamp program at the factory can also be run, and the speed of water lamp display can be controlled through an adjustable rheostat.
Correctly establish the connection between the debugger and the target board, and read the ID
Demo board comes with water lamp program
At this time, we can also download the previously compiled blink led program directly into the demo board. The author probably calculated the download time of about 9s, and then the author started to introduce the offline download method of the debugger. First, with the correct connection, click programmer - > programmer to go - > send image in memory of the MPLAB ide software to download the program into the EEPROM of the debugger. The software settings are shown in the figure below
Download the software program into the EEPROM of pickit3 debugger
After the download is completed in about 4 seconds, we can remove the connection between the power Mini USB cable and the computer, prepare an additional portable mobile power supply, or directly use a 5V / 1A power adapter. The output current is required to be at least 100mA to maintain the current of the debugger and the target board. In fact, because the working current of our demo demo board is small, Power can be supplied through the debugger, and the working current of the target board that needs to be supplied by the debugger cannot exceed 30mA, otherwise it is best to use additional external power supply to supply power to the target board.
The following figure shows the three states of offline Download:
Before downloading, the power LED is always on, the active LED flashes slowly, and the status LED is off
LED status indication before pickit3 offline Download
Click the function key of pickit3 debugger to perform offline download. During download, the power LED is always on, the active LED is always on, and the status LED flashes
LED status indication when pickit3 is downloaded offline
After downloading, the power LED is always on, the active led returns to slow flashing, and the status LED changes from orange flash to yellow, waiting for the next burning
LED status indication after pickit3 offline Download
The speed of offline download is faster than that of online download. It takes only 7S. As the author said earlier, this offline download function is very practical in the development process or small batch trial production.
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When you do not need to use the function of offline download, just connect the debugger to the computer again, open the MPLAB ide software, and click No in the dialog box whether to keep offline download, as shown in the following figure
Cancel offline download of pickit3 debugger
In addition to downloading and online programming, pickit3 debugger can also debug program code with MPLAB ide software. However, its practicability is not very good. Sometimes there is no response and the software pretends to be dead. Compared with the popular tools such as keil and IAR on the market, pickit3 debugger is deficient. Perhaps in view of this, microchiop has designed another more powerful ide design tool MPLAB X.
MPLAB x can be downloaded through the official website of microchip. After installation, the software can be opened. The interface of MPLAB x is more beautiful and guided, which will not make people feel overwhelmed and don't know how to use it. However, the software started slowly and took nearly 20 seconds.
MPLAB x ide development tool interface
A major change of MPLAB x relative to MPLAB can be said to be detailed when creating project files. For example, for a chip of PIC series, the compiler setting project will prompt you which compilers you currently have and which compilers you do not install but support the compilation of the code of this series of microcontrollers, You can refer to the following figure to compare the settings before and after installing the xc8 compiler.
Before installing the xc8 compiler
After installing the xc8 compiler
In addition to the settings of new projects, MPLAB x can import MPLAB project files, which can help you transition from MPLAB ide v8.xx to MPLAB x version and complete code migration. Let's take a look at downloading the previous program into the demo demo board through MPLAB X. a problem was found in the actual operation. We can't find the setting of the output voltage of pickit3 debugger by MPLAB x software (in fact, it is possible through the file - > project properties - > pickit 3 power option). There is no way. We can only provide external power for the demo demo board for the time being.
Download and run blink led program through MPLAB x
However, the functions of PIC Series MCU have become more and more, and the power consumption has also increased. The output current (30mA) provided by pickit3 is a little stretched, so the setting of its output voltage needs to consider the actual power consumption of the board before deciding whether to turn it on. MPLAB x still retains the function setting of offline download, which can be found in the download drop-down bar. Of course, the most important role of pickit3 is not to download, but to debug. Fortunately, the debugging function of MPLAB x software has been greatly improved. There is no software non response that may sometimes occur on MPLAB. Pickit3 is also like the characteristics of emulators on the market, with functions such as one-step debugging and breakpoint debugging, Interested friends can buy one and have a good toss.
After a preliminary experience with MPLAB and MPLAB x, the fundamental difference between the two IDE tools lies in their ideas, as shown in the figure below
MPLAB ide v8.00 and MP
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