Examples

Usage examples of this micropython-winbond library

General

An example of all implemented functionalities can be found at the MicroPython Winbond boot and main files

Setup Flash

from machine import SPI, Pin
from winbond import W25QFlash

# the pins and SPI bus can be different on each board
#
# check MicroPython SPI documentation
# https://docs.micropython.org/en/latest/library/machine.SPI.html
# for Device/Port specific setup
# check the docs of your device for further details and pin infos
CS_PIN = Pin(5)
spi = SPI(0)
# for the BE-ESP32-01 use
# CS_PIN = Pin(10)
# spi = SPI(2, 2000000, sck=Pin(12), mosi=Pin(11), miso=Pin(13))

flash = W25QFlash(spi=spi, cs=CS_PIN, baud=2000000, software_reset=True)

# get Flash infos/properties
print("Flash manufacturer ID: 0x{0:02x}".format(flash.manufacturer))
print("Flash Memory Type: {}".format(flash.mem_type))
print("Flash Device Type: 0x{0:02x}".format(flash.device))
print("Flash size: {} bytes".format(flash.capacity))
# manufacturer: 0xef
# mem_type: 64
# device: 0x4016
# capacity: 4194304 bytes

Format Flash

Note

The flash has to be formated once as an initial step. This step is not required again. Depending on the flash chip size this might take up to 60 seconds.

import os

# create filesystem on the flash chip, approx. 10 sec
os.VfsFat.mkfs(flash)

# format and erase the flash chip content, approx. 40 sec for 128MBit/16MB
flash.format()

Mount Flash

flash_mount_point = '/external'

os.mount(flash, flash_mount_point)

Note

The flash has to be formated once as an initial step, an OSError: [Errno 19] ENODEV will be thrown otherwise. Refer to the Format Flash section above.

Identify Flash

Identify the flash chip manufacturer, device ID and device capacity in bytes.

flash.identify()
# manufacturer: 0xef
# mem_type: 64
# device: 0x4016
# capacity: 4194304 bytes

Example files

The boot.py code will perform the following steps:

  • create a flash object on the SPI bus with a bus speed of 2MHz, chip select on machine pin x and a software reset interface. Check the datasheet of your flash chip whether software reset is supported.

  • try to mount the external flash to /external

    • in case of OSError 19 the filesystem will be created first

    • otherwise the complete flash will be erased and the filesystem created

    • finally mount the external flash

The initial steps of formatting the flash and creating the filesystem will take around 45 seconds on a 128MBit (16MB) Winbond flash.

The main.py code will perform the following steps:

  • list all files and folders on the boards root directory

  • try to read a file named some-file.txt on the external flash

    • if the file does not exist, it will be created

  • extend the content of some-file.txt on the external flash with new content

  • list all files and folders on the external flash directory

A successful output of a first run after a soft reboot should look similar to this

MPY: soft reboot
manufacturer: 0xef
mem_type: 64
device: 0x4018
capacity: 16777216 bytes
Mounting the external flash to "/external" ...
Failed to mount the external flash due to: [Errno 19] ENODEV
Creating filesystem for external flash ...
This might take up to 10 seconds
Filesystem for external flash created
External flash mounted to "/external"
boot.py steps completed
Entered main.py
Listing all files and folders on the boards root directory "/":
['external', 'boot.py', 'lib', 'main.py']
No test file "some-file.txt" exists on external flash "/external", creating it now
Listing all files and folders on the external flash directory "/external":
['some-file.txt']
Finished main.py code. Returning to REPL now
MicroPython v1.18 on 2022-01-17; ESP32 module with ESP32
Type "help()" for more information.
>>>
MPY: soft reboot
manufacturer: 0xef
mem_type: 64
device: 0x4018
capacity: 16777216 bytes
Mounting the external flash to "/external" ...
External flash mounted to "/external"
boot.py steps completed
Entered main.py
Listing all files and folders on the boards root directory "/":
['external', 'boot.py', 'lib', 'main.py']
Test file "some-file.txt" exists on external flash "/external"
This is its content:
Hello World at 698411330

Appending new content to "/external/some-file.txt"
Listing all files and folders on the external flash directory "/external":
['some-file.txt']
Finished main.py code. Returning to REPL now
MicroPython v1.18 on 2022-01-17; ESP32 module with ESP32
Type "help()" for more information.