"Arm has a variety of processor cores, and various manufacturers authorized by arm have launched a wide variety of processor chips. Therefore, the market is full of all kinds of ARM development boards and evaluation boards, with different performance and very different prices. After arm acquired KEIL, a famous embedded development tool, it continued to launch various embedded development schemes and evaluation suites. The official evaluation suite released by keil has advantages that other manufacturers do not have.
Today, I'd like to introduce to you the latest keil mcbstm32f400 arm Evaluation Kit, which is a development tool based on arm cortex-m4 core. The core microcontroller on the board adopts stm32f407 series. The application program of stm32f407x microcontroller series can be written and tested on the F400 evaluation board. The evaluation board contains various peripherals and includes functions such as 3-axis digital accelerometer, gyroscope, digital camera and microphone. And each kit (mcbstm32f400ume) provides ulink-me debugging adapter.
The package of F400 Evaluation Kit includes:
One mcbstm32f400 evaluation board
One ulink-me debugger and a 10 pin JTAG cable (1.27mm spacing)
Two usb-a to micro USB cables
Getting started manual
Core chip
The core chip of F400 evaluation board is stm32f407 series microcontroller with cortex-m4 core. Cortex-m4 is a high-performance processor of arm. Compared with the previous Cortex-M3, it increases the DSP expansion of CPU and a single precision floating-point operation unit (FPU) to support the single precision digital signal processing instructions and formats of arm. Cortex-m4 processor realizes the combination of real-time control of microcontroller and signal processing capability of DSP, widens the application range of products, and can provide more flexible solutions for motor control, automobile, power management, embedded audio and industrial automation markets.
Stm32f4 series microcontroller on the evaluation board adopts 90 nm process and unique art accelerator, and the processing performance reaches 210 DMIPS / 469 at 168 MHz. STM32 F4 series remains pin to pin and software compatible with STM32 F2 series, provides more static random access memory, and improves some peripherals, such as full duplex I2S bus, improved real-time clock (RTC) and faster analog-to-digital converter (ADC).
Stm32f407ig integrates a large number of peripheral controls, covering almost all common interfaces of embedded applications. It is an all-round microcontroller. It even includes LCD interface and camera control interface. Refer to the data manual to see some of its main parameters:
Cortex-m4 core, frequency up to 168mhz
192kb SRAM, 1MB flash and various static memory interfaces (such as compact flash, SRAM, PSRAM, nor and NAND)
LCD parallel interface
2-channel 12 bit D / A, 24 channel 12 bit a / D
Up to 17 timers
Up to 140 gpios with interrupt function
15 channel serial communication interface (including ISP, I2C, USART, UART, can, etc.)
2-way USB OTG (FS + FS / HS)
10/100 Ethernet MAC
Parallel camera interface
RTC
SWD / JTAG debugging interface and cortex-m4 ETM debugging mode (embedded trace macrocell)
hardware component
Many of Keil's evaluation boards have the same structure and size. The style is unified, which can simplify the design and be easy to identify. The same is true for the mcbstm32f400 evaluation board. The board is rectangular, with a size of 170mm x 124mm. When I first saw it, I felt that there were so many peripherals and jumpers on the board.
This evaluation board is mainly used to evaluate the performance of stm32f407 series microcontroller chip and software development, so the peripherals on the board are really complete, and the peripheral interfaces of the microcontroller can be tested on the evaluation board. The PCB board adopts a 4-layer design, and the four corners of the board are provided with fixed supports. After all, it is produced by the original factory, which is a very mature and considerate design. Let's first look at the block diagram and parameters of F400 evaluation board:
168mhz stm32f407ig arm cortex-m4 core microcontroller, 176 pin BGA package
Memory: 8MB nor flash, 512MB NAND flash, 2MB SRAM, 8KB I2C EEPROM (with NFC interface)
2.4 inch color QVGA TFT LCD (with touch function)
10/100 Ethernet
USB 2.0 Full Speed - USB, USB-OTG, & USB Host
USB 2.0 High Speed - USB, USB-OTG, & USB Host
1 can bus interface
serial interface
MicroSD card interface
5-way lever
3 digital axis accelerometer
3-axis digital gyroscope
Analog voltage input (potentiometer)
Audio codec (with speaker / microphone)
300000 pixel VGA camera
4 buttons
8 LED
3 JTAG interfaces
Power supply socket
With such complete functions, the hardware of the evaluation board is quite complex, and there are many ICs on the board. However, the schematic diagram of the evaluation board is public and can be used to refer to and study the design of the official public version. The following is a detailed breakdown of its hardware design:
1. Microcontroller
ST's latest cortex-m4 core stm32f407ig, 176 pin BGA package. Stm32f407 chip has 1MB flash and 192kbram memory, external 25MHz crystal oscillator and 32.768KHz RTC clock. There are built-in 16mhz clock and 32kHz RC oscillation circuit inside the chip, so the pins of the two clocks can also be used as GPIO. Wiring copper wires (SJ1, sj2, SJ3 and SJ4) can be seen on the PCB as reserved. If you need to use the clock pin as IO pin, you can short-circuit these wiring and remove the external clock at the same time.
The microcontroller chip is packaged in BGA, so it is impossible to debug with oscilloscope and other equipment. Fortunately, the prototype area is reserved on the evaluation board to lead out all 140 IO pins, power supply and ground of the microcontroller, which not only facilitates the measurement signal, but also expands the function as needed. The IO pin is a pin directly connected to the microcontroller chip, so be careful with the signal voltage to avoid burning the chip. The following figure is the prototype expansion area of the evaluation board:
2. Memory
The F400 evaluation board is equipped with various types of memory, including:
8MB (4mx16) nor flash memory m29w640fb70n6e.
2MB (1mx16) SRAM memory is61wv102416bll-10mli.
512MB (512mx8) NAND flash memory mt29f4g08a.
8KB (2kx32) EEPROM memory m24lr64-r.
All the devices on the F400 evaluation board are on the front of the PCB, and only the NAND flash memory is on the back of the PCB. EEPROM m24lr64-r is a dual interface memory, including an I2C interface and an RF interface, which can accept wireless carrier. It can be seen on the board that a 4.7 micro Heng inductance coil is connected next to the EEPROM, so that NFC signals can be received.
3. Power supply
There are three power supply modes for the evaluation board: power socket and two micro USB ports.
The power socket adopts a standard 2.1mm aperture socket with an input range of 8v-12v. It provides 5V and 2A voltage through the DC-DC converter lm25011my of TI company. Two micro USB can also provide 5V voltage through the computer. Three 5V voltage lines are connected in parallel through b340 rectifier, so as to prevent interference between voltages.
5V voltage generates 3.3V digital circuit voltage and analog circuit voltage through two 3.3vldo voltage regulators ld1117s33. The maximum working current of F400 evaluation board is 375ma, so one USB port is enough to provide the current required by the evaluation board (if you want to drive high current peripherals, you need to connect to the power socket).
There is also a button lithium battery cr1220 on the board to provide power for the RTC of the microcontroller. When the jumper J1 is connected to the bat, the RTC can be kept working even if there is no 5V power supply.
4. JTAG
Three kinds of debugging interfaces are provided on the board: Standard JTAG (20 pin 2.54mm spacing), standard cortex debugging port (10 pin 1.27mm spacing), and cortex + ETM interface (20 pin 1.27mm spacing). In this way, Keil's ULINK series debugging tools can be used (mcbstm32f400ume kit is equipped with ulink-me).
5. LCD
The F400 evaluation board is equipped with a 2.4-inch LCD module with touch function, which is connected to the backplane through a 34 pin socket. The panel adopts ampire's am240320l8tnqw, 2.4-inch (240x320) color TFT LCD and 16 bit interface.
The LCD module includes a 4-wire resistance screen, which is controlled by the touch control chip stmpe811 of ST company.
6. Audio
The evaluation board is also equipped with an audio processing module. The audio processing adopts the low-power stereo codec chip cs42l52 of cirrus logic, and the output can be connected to the speaker and headphone socket. When jumper J6 is short circuited, the audio is output to speaker SPK1, and when disconnected, it is output to headphone socket.
There are two ways of on-board audio input. One is to connect the microphone socket to codec for processing, and the other is to connect the signal directly to the IO of the microcontroller through the on-board digital MEMS microphone sensing chip mp45dt02.
7. Camera
The board contains a CMOS VGA camera cam1, which adopts the ovm7690 of omnivision company, supports 30fps 640x480 image transmission, and the data format is 8 bits. Two 8-bit bus drivers 74lvc245attr are connected to the microcontroller, and jumper J17 enables and turns off camera data.
Since the working voltage of camera chip ovm7690 is 2.6v-3.0v, LDO regulator ld1117str is also used on the board to generate 2.8V power supply. At the same time, the level conversion chip st1g3236dtr is used to provide a 2.8V clock signal.
8. USB interface
Stm32f407 microcontroller has two USB interfaces (FS + FS / HS), which can be used as USB device, USB master control and USB OTG. The micro USB interface on the board is used as a USB device port to connect to the USB control port (computer), and two USB A-type interfaces can be used as USB main control port or USB OTG interface.
The USB main control port or USB OTG port needs to provide sufficient current for external USB devices. Therefore, when using USB A-type interface, the evaluation board needs to provide sufficient current through the power socket. The USB a interface also adopts the current limiting switch chip stmps2141sr of ST company. When the USB control port has overcurrent, short circuit or overheating, the fault lamp (FS) will be lit_ ERR、HS_ ERR）。
Stm32f407 has a USB port (P3) to support FS and HS transmission. When jumper J2 is short circuited, the signal supports USB high-speed transmission through on-board high-speed USB OTG ULPI transceiver stulpi01. When jumper J2 is disconnected, P3 transmission is in full speed mode.
9. Ethernet interface
The microcontroller chip has built-in MAC module, which is connected to RJ45 Ethernet interface through PHY controller st802rt1afr. St802rt1afr is a 3.3V fast PHY interface chip of ST company. It supports 10Base-T, 100base-tx and 100Base-FX. It is packaged with 48 pin LQFP and externally connected with 50MHz crystal oscillator.
10. Serial interface
Stm32f407ig chip can provide up to 6 USART interfaces. There is a 9-pin RS232 serial port (female port) on the evaluation board to evaluate the serial interface of microcontroller,. Jumpers j13 and J14 can be used to select the serial communication port of the microcontroller. The serial signal is connected to the RS232 port through an RS232 driver and transceiver st3232c, and the speed reaches 400kbs.
At the same time, there is a DB9 connector (male port) on the board as the CAN bus interface to evaluate the two can interfaces of the board microcontroller. Select Can1 or can2 through jumper j15. The can signal line is connected to DB9 through a can transceiver sn65hvd230.
11. MEMS
The on-board sensor is also used to evaluate the I2C interface of the chip. The 3-axis accelerometer lis3dh and 3-axis gyroscope l3g4200d with I2C interface are equipped. At the same time, 3 analog input ports are reserved for the 3-axis accelerometer, which can introduce and convert analog signals into digital signals for simulation.
12. GPIO
The F400 evaluation board includes many basic GPIO peripherals, such as 8 LEDs, 4 buttons, potentiometers and 5-way joystick.
The 5-way joystick is controlled by the 8-bit resistance touch screen control chip stmpe811qtr.
13. Micro SD interface
The evaluation board is equipped with a micro SD card socket.
14. Jumper
J1
BAT/3.3V
Select the RTC power supply of the microcontroller
J2
USBHS_ EN
Enable the highspeed mode of the high-speed USB port
J3
BOOT1
Connect the microcontroller boot1 pin high or ground
J4
BOOT0
Connect the microcontroller boot0 pin high or ground
J5
M_ DATA
Connect the data line of the mic sensor to pin PC3
J6
LS
Select headphone output / onboard speaker
J7
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