The first time I knew FreeScale was when I was a freshman. At that time, I only heard about the FreeScale car race, and I didn't know it. In the summer vacation of my freshman year, I began to participate in the school's electronic design contest. At that time, I just had a concept of what a single chip computer was, but I was deeply attracted by them. Because for the first time, I can translate my thought into actual mechanical expression. Lingyang Technology's 16 bit MCU is the first development board in my life. Later, I thought I was really a newborn and not afraid of tigers. I skipped the 8 bit MCU and directly carried out the "era" of 16 bit MCU. The subject of my college graduation was "control of six axis robots", and I used a 32-bit ARM embedded development board. At that time, the ARM architecture was still A8 A9. When I entered the work, I found that, The company has used Cortex M1/M2, which is developing rapidly.

The ARM development board we are going to introduce to you today uses Cortex  M4， Frequency up to 120MHZ Arduino compatible ™ R3， But in fact, the most critical point of this motherboard is: Programmable OpenSDAv2 debug circuit. Now let's talk about this development board in detail.

The packaging of Freescale FRDM-K64F development board is very simple and easy to win. The development board implements RoHS standard, without Pb, and the development board can be recycled. The drawback is that the development board is not sealed with an anti-static bag, but placed directly in the box.

By default, there is only one development board in the development board box, and there are no other external modules or accessories.

Package instruction, two in one, Description of Freescale FRDM-K64F development board peripheral interfaces and pins. The characteristics are as follows:

(1) MK64FN1M0VLL12 MCU (120 MHz, 1 MB flash memory, 256 KB RAM, low power consumption, amorphous USB and 100 pin thin quad flat pack (LQFP))

(2) Dual purpose USB interface with Micro-B USB connector

(3) RGB LED FXOS8700CQ accelerometer and magnetometer Two user buttons

(4) Flexible power supply options - OpenSDAv2 USB, Kinetics K64 USB and external power

(5) Arduino compatible ™ I/O connector of R3 provides easy access to MCU I/O

(6) The programmable OpenSDAv2 debugging circuit supports CMSIS-DAP interface software and provides the following functions: Mass Storage Device (MSD) flash programming interface CMSIS-DAP debugging interface can provide operation control debugging function through driverless USB HID connection, compatible with IDE tools Virtual serial port Open source CMSIS-DAP software project

(7) Self contained Ethernet SDHC interface

(8) Expandable module: RF Module: nRF24L01+Nordic 2.4GHz radio, Bluetooth module: JY-MCU BT circuit board V1.05 BT.

MK64FN1M0VLL12 MCU 

As we said earlier, one of the features of this development board is OpenSDAv2, which is called OpenSDA， namely It uses the USB flash disk Device mode to write code, which eliminates the need to install additional debugger drivers. Moreover, its firmware update and stability are commendable. In the past, we used to need an external debugger to write or debug programs, but now we can directly use this to complete. The OpenSDA debugger not only facilitates the establishment of the entire development platform, but also provides a variety of serial communication, Flash programming and debugging operation methods, which allows engineers to evaluate and develop Freescale Kinetics series microcontrollers conveniently and quickly without increasing research and development costs.

How is this function realized? The key lies in this FreeScale chip, M20AGV, whose code is open source and can be studied by rising friends.

Acceleration sensor and magnetic field sensor chip can be used for attitude control.

From the overall block diagram and actual finished products of Freescale FRDM-K64F development board, the design of the development board is compact and compact. It is also very convenient to use in small robots or cars. With acceleration sensors, magnetic field sensors, in addition to RF or Bluetooth modules, remote control can be very convenient, The next step is how to use this development board.

Since there is no learning CD, the best way to really start this development board quickly is to open it“ ”。

Not only can we have a very comprehensive understanding of the performance of this single chip microcomputer, but also can we find data manuals, reference manuals, user's guide, development board schematics, etc. The most difficult thing is that the website combines various ways of image, text, video and post communication to guide users to get started quickly.

We can choose to download the development kit+integrated development environment (IDE) for local development debugging, or we can directly use ARMmbed for online development. Generally, if we only debug the development board, we can choose online, but if we really develop our own projects, we naturally choose the former.

Finally, there are two development projects. The first one is Freescale FRDM-K64F development board is connected with GSM module to realize dialing and SMS functions.

The second is a "tall project", Positioning project between Freescale FRDM-K64F development board and China Beidou module.

Summary: Compact and compatible Arduino ™ R3 I/O, powerful OpenSDAv2、 Equipped with acceleration and geomagnetic sensors, configurable Bluetooth, 2.4G wireless communication module, based on Cortex M4 Freescale FRDM-K64F development board can easily exert its strength in many occasions. Small development boards also meet people's needs for high integration and small space, OpenSDAv2 allows engineers to debug development boards more easily and effectively.