(r2) AccessingThePythonInterpreter < IoT_Course

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---+ Accessing the Python interpreter
---++ !MicroPython

!MicroPython implements the Python 3.4 syntax. It is Open Source and can be downloaded from its [[https://github.com/micropython/micropython/][github repository. ]]There are versions for different kinds of processors and descriptions on how to build and flash the interpreter. The ESP32 port is based on the ESP-IDF development environment provided by Espressif, the company behind the ESP processors. They also provide the <i>xtensa-esp32-elf-gcc </i>cross compiler and associated libraries. Going into details on how we built the interpreter would go beyond the limits of what this course can teach. Let's suppose that the interpreter in already installed in the ESP32 flash and ready to run.

Details about !MicroPython is found in its [[https://docs.micropython.org/en/latest/index.html][documentation]], which has a chapter dedicated to [[https://docs.micropython.org/en/latest/esp32/quickref.html][ESP32 functionality]].

For convenience a !MicroPython firmware binary as well as the scripts needed to erase the ESP32 flash and to program it with the firmware are given here:

%ATTACHURL%/firmware.bin

%ATTACHURL%/esp32_erase.sh

%ATTACHURL%/esp32_flash.sh
---++ Accessing the interpreter though the serial line

In order to connect to the ESP32 we need a serial terminal emulator like _minicom,_ _gtkterm_ or seyon. Later on we will use <i>thonny </i>as an editor to write our Python scripts and save them on the PC but also to connect to the ESP32 through<i> thonny's</i> command window.

Here I give you an example how to configure _minicom_ for use with !MicroPython on the ESP32. First you must start minicom as root with the option "-s":

<verbatim>minicom -s</verbatim>

<img alt="minicomConfig.png" height="527" src="%ATTACHURL%/minicomConfig.png" title="minicomConfig.png" width="786" />
<verbatim> </verbatim>

Then you can save these settings as default when starting _minicom_.

<img alt="minicomSave.png" height="223" src="%ATTACHURL%/minicomSave.png" title="minicomSave.png" width="298" />

Finally you can start minicom normally without any options and you will see that !MicroPython says "hello" with its characteristic prompt: "&gt;&gt;&gt;".

In the screen dump below I typed the command
<verbatim>help()</verbatim>

and you see the first part of !MicroPythons answer.

<img alt="minicomHelp.png" height="527" src="%ATTACHURL%/minicomHelp.png" title="minicomHelp.png" width="786" />

Now you can interact with !MicroPython through its Read, Evaluate, Print Loop (REPL). Here a simple example:

<img alt="microPythonSession.png" height="437" src="%ATTACHURL%/microPythonSession.png" title="microPythonSession.png" width="1002" />

-- %USERSIG{UliRaich - 2020-04-25}%

---++ Comments

%COMMENT%

Attachments

Topic attachments
I	Attachment	History	Action	Size	Date	Who
sh	esp32_erase.sh	r1	manage	0.2 K	2020-05-07 - 10:01	UliRaich
sh	esp32_flash.sh	r1	manage	0.2 K	2020-05-07 - 09:58	UliRaich
bin	firmware.bin	r1	manage	1444.8 K	2020-05-07 - 09:58	UliRaich
png	microPythonSession.png	r1	manage	60.7 K	2020-04-25 - 19:46	UliRaich
png	minicomConfig.png	r1	manage	43.0 K	2020-04-25 - 18:28	UliRaich
png	minicomHelp.png	r1	manage	57.7 K	2020-04-25 - 18:28	UliRaich
png	minicomSave.png	r1	manage	15.1 K	2020-04-25 - 18:28	UliRaich

Topic revision: r2 - 2020-05-07 - UliRaich