Will try ampy, thanks much!

What do you use to transfer files both ways?

I use Adafruit ampy because it supports get and put to transfer files both ways. You could also try the Thonny IDE that @lukasmaximus mentioned in the other thread. I haven’t tried that yet.

I did try Mu IDE today with an m5stickC running the mainline MicroPython v1.12 firmware, but I wasn’t successful getting the REPL to work. It didn’t seem to detect the serial port connection to the m5stickC. However, Mu REPL did work for me with an M5Stack core running uiFlow v1.5.0 though.

115200

I followed your tip and got the prompt now! My mistake (habit of ESP8266 days) was thinking 9600 is a safe speed, which apparently isn't. Also didn't know about Ctrl-C until you mentioned it.

What do you use to transfer files both ways?

I'm on a Mac and I use the OSX Terminal and the screen utility to access the REPL. On Windows, you might need to use Putty or something similar. With the uiFlow firmware burned to your m5stickC you can access the REPL.

screen /dev/tty.usbserial-514A6FFF41 115200

Once I'm in the screen session, I press Ctrl+C a few times to get to the REPL prompt. In the output below, I'm pressing Ctrl+C after it says "start m5ucloud monitor":

MPY: soft reboot
I (683470) [TFTSPI]: attached display device, speed=8000000
I (683470) [TFTSPI]: bus uses native pins: false
[ M5 ] node id:d8a01d698f30, api key:6501754B
start m5ucloud monitor

Unhandled exception in thread started by <bound_method>
Traceback (most recent call last):
  File "flowlib/lib/time_ex.py", line 69, in timeCb
KeyboardInterrupt: 
Traceback (most recent call last):
  File "flow_usb.py", line 28, in <module>
  File "flowlib/m5ucloud.py", line 45, in run
  File "flowlib/lib/time_ex.py", line 69, in timeCb
KeyboardInterrupt: 
MicroPython v1.11-321-gac7da0a70-dirty on 2020-02-25; ESP32 module with ESP32
Type "help()" for more information.
>>> 
>>> 
>>> import os
>>> os.listdir()
['image_app', 'flow_usb.py', 'config.json', 'main.py', 'res', 'boot.py', 'img', 'config.py', 'flow.py', 'blocks', 'apps', 'debug.py']
>>> 
>>> f = open('main.py')
>>> f.read()
'from m5stack import *\nfrom m5ui import *\nfrom uiflow import *\n\nsetScreenColor(0x111111)\n\nlabel1 = M5TextBox(24, 70, "TEST", lcd.FONT_Default,0xFFFFFF, rotate=0)'
>>> 
>>> f.close()
>>> 
>>> 

In the above example, I open the main.py file (which is the 'test' app I think you are referring to) and read it to the REPL output. You can use other text editors to create your MicroPython programs and upload them to the m5stickC using ampy or another utility. Just save the file as main.py, upload it to the m5stickC and it will run after boot.py.

Here is a good resource to look through.

So I wrote a simple hello world app and managed to run it on the M5StickC without first saving the file in the stick. Trying to write the file results in an error and failed.

My question is: what apps are expected to work in USB mode (since Visual Code REPL doesn't work), and how can I manage the files inside?

@jhfoo
On the m5stickC, hold down the A button immediately after boot/power-on to access the menu. Then you use the B and A buttons to navigate and select.

Thanks mate, I could not remember the sequence.

This was helpful. I use M5Burner to install uiflow v1.4.5.1. Using the web editor I was able to quickly learn some basic python commands.

I notice after installing uiflow I am unable to connect via COM6. Is this normal? How can I do advanced python development without uiflow overheads eg. splitting into multiple files/ modules?

To directly program the M5Stack,
Restart the M5stack and click the right hand button to enter settings, go to "switch to USB mode" and click the middle button.

Micropython mode can allow you to write more advanced code but I recommend Mu or VCode with the micropython plugin.

I notice after installing uiflow I am unable to connect via COM6. Is this normal? How can I do advanced python development without uiflow overheads eg. splitting into multiple files/ modules?