CircuitPython 7 exercises on STM32F411

It's my first try CircuitPython 7.0.0 on STM32F411 minimum development board (Blackpill-like but NOT Blackpill).

cpyF411_info.py

"""
CircuitPython exercise run on STM32F411CE,
get system info.
"""

import os
import microcontroller
import sys

print("- sys.implementation -")
for i in sys.implementation:
    print(i)
print()

print("- os.uname() -")
for u in os.uname():
    print(u)
print()

print("microcontroller.cpu.frequency:\t\t" + str(microcontroller.cpu.frequency))
print("microcontroller.cpu.temperature:\t" + str(microcontroller.cpu.temperature))
print("microcontroller.cpu.voltage:\t\t" + str(microcontroller.cpu.voltage))

cpyF411_listdir.pya

"""
CircuitPython List Files:

The original example list files in SDCard,
now modified to list files in current working directory.

ref:
https://learn.adafruit.com/micropython-hardware-sd-cards/tdicola-circuitpython
scroll down to "List Files"
"""

import os

def print_directory(path, tabs=0):
    for file in os.listdir(path):
        stats = os.stat(path + "/" + file)
        filesize = stats[6]
        isdir = stats[0] & 0x4000

        if filesize < 1000:
            sizestr = str(filesize) + " by"
        elif filesize < 1000000:
            sizestr = "%0.1f KB" % (filesize / 1000)
        else:
            sizestr = "%0.1f MB" % (filesize / 1000000)

        prettyprintname = ""
        for _ in range(tabs):
            prettyprintname += "   "
        prettyprintname += file
        if isdir:
            prettyprintname += "/"
        print('{0:<40} Size: {1:>10}'.format(prettyprintname, sizestr))

        # recursively print directory contents
        if isdir:
            print_directory(path + "/" + file, tabs + 1)

currentDirectory = os.getcwd()
print("Files on filesystem: ", currentDirectory)
print("====================")

print_directory(currentDirectory)

cpyF411_readfile.py

"""
CircuitPython exercise run on STM32F411CE,
get system info.
"""

import os

textfile = "/boot_out.txt"
print("text file:", textfile)
print("========================")
with open(textfile, "r") as f:
    print("Read line from file:")
    print(f.readline())

cpyF411_hello.py

"""
CircuitPython exercise run on STM32F411CE,
toggle onboard LED.
"""

import board
import digitalio
import time

print("\ndir(board):")
print(dir(board))

led = digitalio.DigitalInOut(board.LED)
led.direction = digitalio.Direction.OUTPUT

while True:
    led.value = True   #LED Off
    time.sleep(0.3)
    led.value = False  #LED On
    time.sleep(0.3)
    led.value = True   #LED Off
    time.sleep(0.3)
    led.value = False  #LED On
    time.sleep(0.3)
    led.value = True   #LED Off
    time.sleep(0.3)
    led.value = False  #LED On
    time.sleep(1.5)

---

Next exercise of STM32F411/CircuitPython 7"

~ SSD1306 I2C 128x64 OLED using adafruit_ssd1306 library.