MicroPython/CircuitPython DOS-like shell for microcontroller boards:
(RP2040, ESP32, ESP32 PICO-D4, ESP32-S2/S3, nRF52840, SAMD51, stm32L4+, NXM ARM Cortex-M7, Lilygo T-Deck, M5Stack Cardputer, Cheap Yellow Display - esp32-2432s028)

Check out the demo video at https://www.youtube.com/watch?v=Az_oiq8GE4Y

Related Repositories:
PyDOS_virtkey - The modules needed to add virtual keybaord support to PyDOS
PyDOS_wifi - Generalized Python based microcontroller WiFi API

See the Installation section below to install all the external commands and customize the install for the particular microcontroller you are using. However, if you just want to launch the shell or have limited flash space, the PyDOS.py program will run standadlone so you can simply copy PyDOS.py to your microcontroller to begin.

To start the shell type import PyDOS at the REPL prompt.

At the PyDOS prompt a python program (.py) or batch (.bat) file can be run by simply entering the filename with or without the extension.

setup.bat in the root folder, will prompt the user to indicate the the type of board they are using. The setup batch file will then copy the programs and libraries appropriate for the user's platform to the root and /lib folders of the Microcontroller flash.

(syntax and descriptions taken from https://home.csulb.edu/~murdock/dosindex.html)

When run on an operating system that uses a forward slash as the Directory Seperator, PyDOS requires all switches to immediatly follow the command with no spaces between the command or switches. This is necessary becuase the forward slash directory seperator conflicts with the DOS switch seperator. If the PyDOS environement variable DIRSEP is set to \ (i.e. set DIRSEP=\) PyDOS will utilize the traditional backslash as the directory seperator and DOS switches can then be placed anywhere on the command line. Many of the messages displayed by PyDOS and virtually all external Python programs will not respect this environment variable so the *nix forward slash seperator may still be displayed or required when inputting path names to external programs.

If a command argument contains spaces the argument must be enclosed in quotes.

REM [comment] - Used in batch files to insert remarks (that will not be acted on).

DIR[/P][/W][/S] [path][filename] - Displays directory of files and directories stored on flash.

• /P Pauses after each screenful of information (Q or C to abort listing)
• /W Uses wide list format, displaying file/folder names only
• /S Displays files recursively, traversing any subdirectories

DATE - Displays the current date.

TIME - Displays the current time.

MEM[/D] - Displays available RAM and performs a garbage collection operation

• /D Include debug information when supported by microcontroller board

VER - Displays PyDOS version

ECHO [ON|OFF][message] - Displays messages or turns on or off the display of commands in a batch file.

PAUSE - Suspends execution until a key is pressed.

GOTO label Causes unconditional branch to the specified label. (labels are defined as :label in batch files)

IF [NOT] EXIST filename (command) [parameters]
IF [NOT] (string1)==(string2) (command) [parameters] - Allows for conditional operations in batch processing.
IF [NOT] ERRORLEVEL (number) (command) [parameters]

SET[/P][/A] (variable)=[(string|prompt)] - Inserts strings into the command environment. The set values can be used later by programs.

• /A specifies that the string to the right of the equal sign is a numerical expression that is evaluated
• /P displays the specified prompt string before setting the value of a variable to a line of input entered by the user
  DOS specific environment variables:
  • LIB - The Python search path for importing libraries (the current directory is always searched first but not included in the LIB variable)
  • PATH - The directory search list for executing python scripts and DOS batch files (the current directory is always searched first but not included in the PATH variable)
  • PROMPT - The DOS prompt string
  • _scrHeight - The number of lines on the terminal or screen
  • _scrWidth - The number of columns on the terminal or screen
  • errorlevel - The result code from the previous BAT file or pexec command executed
  • DIRSEP - If set to a backslash (\) PyDOS will use a backslash as the directory seperator character regardless of the seperator used by the local filesystem (i.e. os.sep). If set to anything other than a backslash PyDOS will use a forward slash as the directory seperator character.

PROMPT [prompt text] - Changes or displays the DOS command prompt. Supported strings "$R,$D,$T,$P,$G,$L,$C,$F,$A,$B,$E,$H,$Q,$S,$V,$_,$$" and text literals
Example: prompt $e[44m$p$g sets the backgound blue (if the terminal supports vt100 escape sequences) and displays the current directory followed by a ">"

Character	Description
---------   -----------
$R          Available RAM
$D          Current date
$T          Current time
$P          Current path
$G          > (Greater than sign)
$L          < (Less than sign)
$C          ( (Left parenthesis)
$F          ) (Right parenthesis)
$A          & (Ampersand)
$B          | (Pipe symbol)
$E          ANSI escape code (code 27)
$H          Backspace (delete last character from displayed prompt)
$Q          = (Equal sign)
$S          Space
$V          Version number
$_          ENTER-LINEFEED
$$          $ (Dollar sign)

PATH [path1;path2;...] - Changes or displays the directory search list for executing python scripts and DOS batch files

RENAME (REN, MOVE, MV) [path]filename [path]filename - Changes the filename under which a file is stored.

DELETE (DEL)[/S] [path]filename - Deletes files from disk.

• /S Delete specified files from all subdirectories

TYPE (MORE)[/P] [path]filename - Displays the contents of a file.

• /P Pauses after each screenful of information (Q or C to abort listing)

CD [[d:]path] - Displays working (current) directory or changes to a different directory.
CD .. - Changes to parent directory of current directory.

MKDIR (MD) path - Creates a new subdirectory.

RMDIR (RD)[/S] path - Removes a subdirectory.

• /S Removes all directories and files in the specified directory and the directory itself

COPY[/Y] [path]filename [path][filename] - copies files.

• /Y Suppresses prompting to confirm you want to overwrite an existing destination file

EXIT - In a batch file returns to PyDOS, at PyDOS prompt terminates PyDOS and returns to REPL.

PEXEC[/Q] [python command] - Executes a single python command.

• /Q Supresses error message if error condition occurs (errorlevel variable is set)

An autoexec.bat batch file will automatically execute when PyDOS starts.

External programs may require one-time board configuration using setup.bat

pydospins.py - Displays the GPIO pins for sound output and I2C for the particular board PyDOS is running on.

PyBasic.py [[path]basic program file .py|.bas] - a Basic interpreter from https://github.com/richpl/PyBasic. Tweaked and modified to run on Micropython and Circuitpython. interpreter.py, basicparser.py, basictoken.py, flowsignal.py, lexer.py, program.py, basicdata.py

runasthread.py [[path]python program file[.py]] (Micropython only) - This program will attempt to launch a python program on the second RP2040 core. Threading is experimental on Micropython so it's not difficult to crash the microcontroller using this program. I have not found a way to kill a thread started on the second core so be sure any threads you launch will shutdown on their own or monitor a global variable or thread.lock to respond to a shutdown request (see the badblink.py for an example).

runvm.py [[path]python program file[.py]] - This program is used to launch Python programs that require more memory than is available while running PyDOS. runvm will write a code.py/main.py file which launches the specfied python program after the next soft reboot. The program then uses supervisor.reload() for CircuitPython or sys.exit for MicroPython to perform a reboot (sys.exit requires a Ctrl-D to complete the operation). The specified python program is "wrapped" in some code that passes any command line arguments and the PyDOS environment variables to the newly booted environment as well as code that restores the original code.py/main.py files and causes a second soft reboot returning control to PyDOS.

edlin.py [[path]filename] - line editor inspired by DOS edlin. Intial program structure of line editor by Joesph Long https://github.com/j-osephlong/Python-Text-Editor

edit.py [[path]filename] - shell to load full screen editor from https://github.com/robert-hh/Micropython-Editor

xcopy.py[/S][/Y][/V] [path]filename [path][filename] - a more robust version of the copy command

• /S Copies specified files from directories and subdirectories, except for empty ones
• /Y Suppresses prompting to confirm you want to overwrite an existing destination file
• /V Performs a verification read of the copied file to ensure it matches the source

fileview.py [[path]filename] - scrollable text file viewer

sdmount.py [[mount path][,pydos spi bus#]] - mounts an sd card to the file system
sdumount.py [mount path] - dismounts an sd card from the file system

setdate.py [mm-dd-yy] - initalizes the real time clock to an entered date
settime.py [hh:mm:ss] - initalizes the real time clock to an entered time
ntpdate.py [timzone offset] (WiFi enabled boards) - sets the time and date using the Internet NTP protocol

diff.py [filename1,filename2] - performs a file comparison

sound.py [Frequency,Duration(miliseconds),Volume] - outputs a sound to a speaker cicruit connected to GPIO pin defined in lib/pydos_bcfg.py
tsound.py - test program that plays a short sound sequence
piano.py - emulates a small piano keyboard

i2cscan.py [bus number] - scans the I2C bus and displays any found device addresses

CircuitPython LCD libraries from https://github.com/dhylands/python_lcd
lcdprint.py [text to display] - displays text on an I2C LCD display
lcdscroll.py [text to scroll] - scrolls text on an I2C LCD display
temperature.py - displays temperature value from onboard temperature sensor to screen and I2C LCD display

basicpython.py - Shell modeled after basic interpreter shell from https://github.com/tannewt/basicpython

blink.py [led pin number] - program to blink onboard LED

rgbset.py [rgb led pin number] - program to set the rgb color of an onboard neopixel or dotstar
rgbblink.py [rgb led pin number] - program to blink an onboard neopixel or dotstar
rgbrainbow.py [rgb led pin number] - program to color cycle an onboard neopixel or dotstar

reboot.py - performs a soft reboot (Micropython requires a Ctrl-D to complete)

keys.bat - (Keyboard Featherwing/BBQ Keyboard only) Displays keyboard mappings for hidden keys and functions
ui.bat [u/k] - (Keyboard Featherwing/BBQ Keyboard only) Switches between using the Keyboard Featherwing and USB Serial port for PyDOS I/O

fs.py [ro/rw] - (Circuitpython only) By selecting the "RO" option the flash mode is set such that when the microcontroller is power cycled or hard reset, the host computer will have read/write access to the flash and the microcontoller will be restricted to read only access. To give PyDOS access to the flash after switching to this mode the boot.py file must be replaced or modified from the host computer so that it contains the following instructions:

import storage
storage.remount("/",False)

and then power cycled or hard reset.

WiFi enabled boards only
wifi_finance - Displays the current Nasdaq prices by connecting to a financial website and scraping the information.
wifi_weather - Displays the 7 day forcast from api.weather.gov

The setup.bat file will identify the board being used from board.board_id or sys.implementation._machine and attempt to copy a customization file from the cpython or mpython /boardconfigs directory. If a matching config file is not found the default /lib/pydos_bcfg.py file will be used.

The pydos_bcfg.py file acts as a library which contains a single dictionary opject, Pydos_pins.

The recognized keys of the Pydos_pins dictionary are:

TUPLES (pin number, Text description of identified pin)
example: 'led' : (25, "GP25")

led - Micropython may use text identifer (i.e. "led") rather than pin number
sndPin
neoPixel
neoPixel_Pow
dotStar_Clock
dotStar_Data
dotStar_Extra
dotStar_Pow
I2C_NUM - MicroPython hardware I2C number
SCL
SDA

LIST OF TUPLES
First tuple in list used for machine/board SD dedicated SPI (board.SD_SPI)
Last tuple in list used for machine/board general use SPI (board.SPI)
example: 'MISO' : [(43, "DAT0 D43 Internal"), (12, "MISO D12")]

SPI_NUM - MicroPython hardware SPI number
SCK
MOSI
MISO
CS

CALCULATED DATA

sndGPIO - digitalio.DigitalInOut(sndPin)
KFW - Flag indicating use of Keyboard FeatherWing (True/False)
I2CbbqDevice - I2C device being used for the KFW keyboard
SD - list of sdcard objects
SDdrive - list of mount points for mounted SD cards

Whenever possible PyDOS and the bundled external programs work equally well on MicroPython or CircuitPython and on any of the supported micro controller chip families. To assist in reaching this goal PyDOS_wifi, a simplified Wifi library, is being developed which provides a unified Wifi API that works the same under both MicroPython and CircuitPython on ESP32xx, Pico W and Arduino Nano based Microcontrollers.

For PyDOS_wifi API documentation see https://github.com/RetiredWizard/PyDOS_wifi

Before copying PyDOS files

If the board you're using has limited flash storage, as is the case with the Pico W, you can delete either the cpython (if you're not using CircuitPython) or mpython (if you're not using MicroPython) folder from the downloaded repository files. Within the remaining Python folder (cpython or mpython) are folders for specific micro controller boards, you can free up further space by deleting anything other than the board you are using (the "Pico W" and "Arduino Nano Connect" boards use the ESP folder). For very limited Flash boards you may want to delete the PyBasic folder until after the setup.bat step is run. Once setup has ben run, delete the cpython and/or mpython folders from the microcontroller and copy as much of the PyBasic directory as space permits to the Microcontroller. Copying just the *.py files is all that's needed for PyBasic to run.

Circuitpython PYSTACK

Thanks to the great work of @bill88t, starting with CircuitPython version 8.0.4, you no longer need to build custom CirucitPython firmware (ESP32 based boards are still being worked on but should have this feature in 8.0.6/8.1.0). PyDOS will run without issue on a standard downloaded CircuitPython image from https://circuitpython.org/downloads.

When CircuitPython boots on a microcontroller the pystack size can be set by the CIRCUITPY_PYSTACK_SIZE value in the settings.toml file. PyDOS comes with this value set to 4000. PyDOS will derive a maximum wildcard length based on this value that should be adequate in most cases, however if you find yourself using particuarly long file names you can increase this parameter value as needed. As you increase the pystack size the memory available for PyDOS to run will decrease slightly.

By the way, if you like PyDOS you'll probably also enjoy ljinux from https://github.com/bill88t/ljinux.

CircuitPython install

To install the CircuitPython image, put your microcontroller board in "bootloader" mode and copy the .UF2 file to the USB mass storage device that shows up on your host computer.

After the .UF2 file is copied to the microcontroller board it should re-boot and a new USB mass storage device should appear.

PyDOS install

To copy PyDOS to the Microcontroller, simply drag the PyDOS directory structure (after removing the mpython folder if space is a concern) to the root directory of the device that appears on the host computer.

If the copy is interrupted for any reason you can delete the boot.py file in the root of the microcontroller flash and try the copy again.

If the copy worked without any errors, you should power cycle the microcontroller board so that the file system is configured to allow the microcontroller to have Read/Write access. When you do this, the host computer will no longer be able to write to the microcontroller mounted drive (usually CIRCUITPY).

If you find yourself locked out of the flash from the host computer and PyDOS is not running, the easiest way to recover is to connect to the REPL, remove the boot.py file and then power cycle the microcontroller board.

    import os
    os.remove("boot.py")

To interact with the microcontroller you will need to connect using a terminal program. On a PC you can use putty and on linux, I would recommend tio. To start tio on linux type the command:

      tio /dev/ttyACM0

You should be presented with either the REPL prompt (>>>) or the PyDOS prompt (>), if not, press return or Ctrl-C. After using Thonny, you may need to press CTRL-B to exit the raw REPL mode that Thonny uses to transfer and execute files.

At the REPL prompt type "import PyDOS" to start PyDOS. From PyDOS type setup to run the customization script.

Once the setup.bat script has been run if you have more files to copy to the microcontroller (PyBasic for example) or you want to run circup, you will need to give the host computer read/write access to the mounted microcontroller drive. This is done by typing "fs ro" at the PyDOS prompt and then power cycling the board.

After running circuip or deleting/copying files using the Host computer, when you want to run PyDOS normally again, edit the boot.py file in the root folder of the mounted microcontroller drive (usally CIRCUITPY) and change the line that reads:

        storage.remount("/",True)  

to:

        storage.remount("/",False)  

and then powercycle the board once again.

Building custom Micropython firmware

Although you can use a standard Micropython image downloaded from Micropython.org to run PyDOS, there are two reasons you may want to build a custom Micropython firmware file.

The first is if you wan to connect up an old school serial terminal to the REPL rather than the standard serial over USB connection. Instructions for building Micropython with this modification can be found in section 2.2 of the Raspberry Pi Pico Python SDK at https://datasheets.raspberrypi.com/pico/raspberry-pi-pico-python-sdk.pdf.

The second is that PyDOS uses a recursive routine to process wildcard operations and the default stack in Micropython limits the recursion depth that can be obtained (With more recent versions of Micropython this has become much less of an issue). This means that PyDOS has to limit wildcard operations, one impact of this is that files with longer file names may not appear in directory listings when wildcards are used. To eliminate this issue a custom Micropython image can be built with the the MICROPY_STACKLESS parameter in py/mpconfig.h changed from 0 to 1.
**Note** I haven't tested a MICROPY_STACKLESS build since ~1.19

MicroPython Setup

Once your microcontroller has Micropython installed and running the best way to copy the PyDOS files and interact with the repl is to use Thonny. Adafruit has a good learning guide for getting started with Thonny here: https://learn.adafruit.com/circuitpython-libraries-on-micropython-using-the-raspberry-pi-pico/micropython-installation.

Download PyDOS from the github repository and after deleting the cpython folder if space is an issue, use the Thonny upload command as described in the Adafruit learning guide to copy the downloaded files to the microcontroller.

To interact with the microcontroller connect over the serial USB port (COMn: /dev/ttyACMx, etc) using a terminal program like puTTY or minicom. You can use the Thonny shell as well however, it does not support the basic ansi escape sequences used by some of the PyDOS functions. One thing to note is that if you connect to your microcontroller with a terminal program after using Thonny, you may need to press CTRL-B to exit the raw REPL mode that Thonny uses to transfer and execute files.

Another option is to use MPRemote. Detailed documentation on installing and using MPRemote can be found at https://docs.micropython.org/en/latest/reference/mpremote.html.

To install PyDOS on the microcontroller board download PyDOS from the github repository and after deleting the cpython folder if space is an issue, set your current directory to the root folder of the downloaded PyDOS repository and use the following command:

mpremote fs cp -r * :

To interact with the microcontroller you can connect to the REPL by simply typing mpremote and pressing return several times until the REPL prompt (>>>) is displayed.

At the REPL prompt type "import PyDOS* to start PyDOS and then type setup to run the customization script.

Note If the board you're using has an onboard SD card slot, Micropython may not mount the flash at the root mount point. In this case copy the PyDOS files to the "/Flash" folder during the initial PyDOS setup. If you plan to boot your device with an SD card inserted you should install PyDOS and run setup before inserting the SD card, then copy boot.py to the SD card.

Note To set up the Seeed (XIAO) nRF52840 board running MicroPython, copy the PyDOS /mpython folder to the /flash folder on the device and then copy the /mpython/boot.py file to /Flash/boot.py and reboot the microcontroller. You should then be able to install PyDOS as usual although the current version of Thonny has difficulty with this board so you should only copy a single folder (i.e. lib, mpython, PyBasic and then all the root files) at a time.

Possible updates depending on RAM impact

• integrate ConnectionManager into PyDOS_wifi
• investigate porting micropython flash mount to circuitpython
• investigate date/time stamp issue on seeed nrf52840 files
• support for connected color displays
• support for touch screens
• Rename should allow wildcards in filenames, i.e. "rename *.bas *.txt" or "rename code.py *.sav"
• Quiet, /Q switches to DEL, RMDIR, COPY, XCOPY commands
• PgUp/PgDwn support in fileview.py
• Properly implement edlin cursor position and append command