This might be helpful for you too.
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Hi guys

I've found that the SD card only seems to be read when it already is inserted when M5Paper is booted / reseted. Or in other words, if M5Paper already is running when I insert the SD card it is not read and going to the Factory Test Test screen returns an SD card failed. On the other hand when the SD card has been recognised and I remove it and then go to the Factory Test Test screen the SD card still passes the test.

Which leads me to my question. In the M5Paper schematic the SD card detect line is connected to GPIO34 and I already verified that reading GPIO34 actually reflects whether an SD card has been inserted or not. Has anyone already tried to use this information?

Thanks
Felix

@world101 Thanks for your reply. For the project I have in mind, I just only need beeps, but if I'm going to hack around, I'll try to attach a speaker since it would allow me to do many other things. For programming I'd go with Arduino.

@lukasmaximus
Thanks Lukas, The problem was loading the font from the internal file system.
After delete all these, and place Serial.begin in the right orde loading of the fonts was no problem. Even my DSEG7Classic-Regular.ttf was loaded correct, and display correct. Converted it with the python file ttf2bin.py was also a succes in use.

One question remains. The command "createRender(168, 256)" is used for drawing bigger text, but are there limitations?
In my case when I put a larger value as 168 the screen still blanks, notting happens, but no error message shows up. The documentation is a bit fuzzy. Please can you explane this command.

Hi guys

Power consumption update: even though the example keeps the M5CoreInk in shutdown mode (everything off except for the RTC) most of the time and only powers up for about 2 seconds every minute to do the update, the built in battery only last for about one week.

Thanks
Felix

I saved a copy of the IP5306_I2C data sheet from a long time ago. In this table, I see the charge current can be set by the CHG_DIG_CTL0 register (see the formula). I would assume the M5stack designers took care of setting the max charge current with that register bits 0 through 4, though I could be wrong.

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If you want the entire data sheet, let me know.

@m5stack Thanks to take it into consideration.
I received my Core2 today. Trying to plug the PLC circuit after removing the bottom seems difficult. On the left side there is a metallic thing (motor?) that push the circuit, and pin headers are really short.

About headers, you sell SMT mount connector in your shop but I think they are 2.5mm long (like the old modules one's)? right? on the micro-module they are 3.5mm (total height 5.84).
For makers like me, if we want to build modules prototype, where can we find compatible trough hole or SMT connectors? I search and found nothing? any ref?

Thank you for your reply. Yes, I did stumble upon the bin2code.py script you mention. The issue is that it doesn't convert the image to raw pixel data (usable by M5EPD_Driver::WriteFullGram4bpp).

After a bit more research, I found a preliminary command using ImageMagik to convert an image to raw pixel data for the M5EPD: convert input.png -depth 4 -negate output.gray

Then convert the raw data to C with bin2code.py : ./bin2code.py output.gray

The result can then be appended to ImageResource.h

@Powersoft
Hello, after contacting M5Stack support the problem is probably the flash chip, M5Stack is replacing my M5Paper.
I had performed this upload test at slow speed but without improvement. Thanks for your help

@powersoft

Found the bin file, under the M5 Burnet

@sodoku Thanks. I just got an email that the M5's are back in stock... Digikey still showing backordered though. Guess i'll have to order from M5 directly.

Thanks for the info

@loboris will push the request forward :)

Hello, could you try to install FTDI drivers as well to see if it can solve the issue for you?

Hello @sodoku

that is actually not a bad idea. I'll keep that in mind. Thank you for suggesting it.

Cheers
Felix

Hello @ckuehnel

Without opening M5CoreInk you probably cannot measure battery voltage with a multimeter. However you can use GPIO35 to read the battery voltage. Check out float getBatVoltage() here.

BTW: I've opened my M5CoreInk today and added some photos to my page (link below). Measuring power consumption in light sleep, deep sleep and shutdown will be next.

Cheers
Felix

UIFlow firmware 1.6.6.1 Seems to fix this issue, please take a look and let me know if you guys have any more concerns :)

I stumbled on this restriction again, and dug a bit deeper in the issue.
It appears that the hardware is not limiting the baudrate, but the M5Stack library. More specifically, M5.begin();
Luckily, you can skip the UART init, and do it yourself like this:

M5.begin(true,true,false);
Serial.begin(2000000);
Serial.flush();

And now it works for 2000000 baud.