"With the release of version 1.9.4 of python, the stm32h7 microcontroller is officially supported by python. Stm32h7, as the highest performance series of STM32 Cortex-M series controllers, how does microprython perform on it? What are the advantages over other models? Here we are at nucelo_ On the h743 development board, take a look at the performance of micro python.
Starting from version 1.9.4, micropython has added the nucleus-h743zi development board to the supported development board. However, the binary firmware file of the development board is not available on the official website. To run micropython, you need to compile the source code yourself. If you have installed the micro Python compilation environment, just enter the following command in the micro Python directory to compile:
make -C ports/stm32 BOARD=NUCLEO_ H743ZI
If you do not have a compilation environment installed, you can refer to another article "compiling micropython under the Ubuntu subsystem of win10". You can install the compilation environment according to the method in this article. This method can also be used for other virtual machines or Ubuntu systems.
If you feel that the installation and compilation environment is too troublesome or the network speed is too slow to install, you can directly download the firmware I compiled, download the firmware to the chip through the on-board stlink, and then you can run it.
Before use, we need to prepare two microusb data cables (data cable of Android mobile phone) and serial port terminal software, such as putty, Kitty, mobaxterm, etc. Note that software such as serial assistant cannot be used because they do not support terminal mode.
Why do you need two data lines? Because st link needs to use a data cable, the USB of stm32h743 on the development board can be connected to another USB. After writing the firmware, first power off once, then connect st link, and then connect the user USB on the other side. If all the operation steps are normal, a pybflash disk will be displayed. We can write files to this disk and run the written program. By default, it will run from the main.py file, so we can put the written program into main.py and let it run automatically.
If it is win10 or MacOS or Linux system, you do not need to install any driver. If it is win7 system, you also need to install a serial driver. The driver is in this pybflash disk. After installation, we can see that there are two serial ports, one is the st link serial port, and the other is the micro Python serial port.
Run a terminal software, the serial port can be set to any of the above two serial ports, and the baud rate is 115200. Select none for flow control. Taking Kitty software as an example, the use of other software is similar:
After setting the parameters, click open Button, you can open the terminal. Press enter. If the > > > prompt appears, it means that the operation is successful. At this time, press ctrl-b to see the version prompt.
As usual, we start with lighting the lights. In micro python, led types are defined by default. We can control them through pyb.led, such as:
pyb.LED(1).on()pyb.LED(1).off()
Because nucleo_ There are three LEDs on the h743 development board, so we can also use them to make a running light:
while 1: for i in range(1, 4): pyb.LED(i).toggle() pyb.delay(500) pyb.LED(i).toggle() pyb.delay(500)
The use of keys is also very easy. There is a built-in switch class in micro python that can be used to read keys. The following procedure controls the status of LED1 by pressing keys:
sw=pyb.Switch()sw()while 1: if sw(): pyb.LED(1).on() else: pyb.LED(1).off()
Timer is also one of the most commonly used functions in programming. In the following program, LED1 and LED3 are controlled in the callback functions of timer 6 and timer 7 respectively, and flash at different frequencies.
TM = PyB. Timer (6, freq = 2) TM. Callback (lambda T: PyB. LED (1). Toggle()) TM2 = PyB. Timer (7, freq = 5) TM2. Callback (lambda T: PyB. LED (3). Toggle()) although stm32h743 has 22 timers, micropython currently only supports timer 14. Timers exceeding 14 can be defined, but will crash once used.
PWM is also a very common function. It is realized by GPIO controlled by timer. It is a special working mode of timer. The following is the method of using PWM in micropthon. The following program controls LED1 (pb0) through CH3 of timer 3 and realizes a breathing lamp by changing the duty cycle periodically.
tm = pyb.TImer(3, freq=1000)pwm = tm.channel(3, mode=pyb.TImer.PWM, pin=pyb.Pin('B0'))pwm.pulse_ width_ percent(20)while 1: for i in range(100): pwm.pulse_ width_ percent(i) pyb.delay(20)
Stm32h743 has two DACs, PA4 and Pa5. Through the DAC, we can output analog voltage and generate various waveforms. As follows, 8-bit (default) and 12 bit modes are used to control the output of DAC respectively:
d1 = pyb.DAC(1)d1.write(100)d1 = pyb.DAC(1, 12)d1.write(3000)
In addition to directly outputting analog voltage, different waveforms can also be output:
Triangular wave
d1.triangle(2048)
white noise
d1.noise(1000)
Predefined user waveforms can also be output. Using this characteristic and the high-speed characteristic of stm32h7, it can be used as a simple waveform generator.
There are many other functions of micropathon, which will not be introduced here. You can run it yourself and experience the convenience brought by micrpathon.
Finally, in order to test the performance of micropathon on stm32h743, we did a comparative test of computing performance, calculated addition, multiplication, division and PI on different hardware platforms, and recorded the calculation time. By comparing the computing time of different hardware, you can intuitively compare the performance (this may be the most comprehensive micro Python computing performance comparison test at present, including all the common hardware at present).
Complete test procedure
from microbit import running_ TImedef pi(places=100): # 3 + 3*(1/24) + 3*(1/24)*(9/80) + 3*(1/24)*(9/80)*(25/168) # The numerators 1, 9, 25, ... are given by (2x + 1) ^ 2 # The denominators 24, 80, 168 are given by (16x^2 -24x + 8) extra = 8 one = 10 ** (places+extra) t, c, n, na, d, da = 3*one, 3*one, 1, 0, 0, 24 while t > 1: n, na, d, da = n+na, na+8, d+da, da+32 t = t * n // d c += t return c // (10 ** extra)def pi_ test(n=5000): t1=running_ time() t=pi(n) t2=running_ time() print('Pi test: ', (t2-t1)/1000, 's')def add_ test(n=1000000, a = 1234, b = 5678): t1=running_ time() sum = 0 for i in range(n): sum = a + b t2=running_ time() print('Add test: ', (t2-t1)/1000, 's')def mul_ test(n=1000000, a = 1234, b = 5678): t1=running_ time() sum = 0 for i in range(n): sum = a * b t2=running_ time() print('Mul test: ', (t2-t1)/1000, 's')def div_ test(n=1000000, a = 1234, b = 5678): t1=running_ time() sum = 0 for i in range(n): sum = a / b t2=running_ time() print('Div test: ', (t2-t1)/1000, 's')print('Speed test starting...')add_ test()add_ test()mul_ test()mul_ test()div_ test()div_ test()pi_ test()pi_ test()
test result
MCU
Dominant frequency
Integer addition
multiplication
division
PI
microbit
nRF51822
16M
sixty-one point eight eight eight
seventy-four point zero seven five
one hundred and three point nine three five
Nucleo_ F091
STM32F091
48M
nineteen point eight eight two
twenty-five point eight nine
fifty-one point seven eight
eighty-two point eight five one
PYBNano
STM32F401
84M
six point nine five nine
seven point two two two
twelve point five two four
eighteen point two three six
Nucleo_ F411
STM32F411
96M
five point eight five eight
six point zero seven six
ten point four seven eight
sixteen point four six seven
PYBV10
STM32F405
168M
three point four three six
three point five six three
six point zero six seven
ten point one eight
STM32L476DISC
STM32L476
80M
eight point five eight six
eight point nine eight nine
fourteen point nine one three
eighteen point nine three two
STM32F7DISC
STM32F746
192M
one point nine four six
two point three zero four
three point six eight
four point five seven nine
Nucleo_ H743
STM32H743
400M
zero point eight five six
zero point nine four two
one point five three four
two point eight three five
ESP8266
ESP8266
80M
fifteen point five four six
eighteen point three zero two
nineteen point seven zero six
forty-one point nine two six
ESP32
ESP32
240M
two point six zero seven
two point seven nine four
three point eight three nine
seven point seven two nine
ESP32_ psRAM
ESP32
240M
three point three six five
three point five five three
eighteen point nine zero two
fifteen point zero one two
ESP32_ LoBo
ESP32
240M
three point three nine six
three point four nine nine
thirteen point zero two
nine point six zero seven
ESP32_ psRAM_ LoBo
ESP32
240M
four point two two eight
four point one five
eighteen point nine zero two
eighteen point seven five seven
The unit of calculation result is seconds
All firmware are updated to the latest version. Except for microbit and esp32 lobo, the firmware version is 1.9.4-479., Read the full text“
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