M5Paper unusable

turgu

Hello all,

I'm facing an issue I can't resolve. The M5Paper i bought sometimes ago refuse to start properly, Got that issue since I purchased the device. I've put it on the side for all that time and tried again to get it works since a week.

Tried to install the testing application and the calculator from the M5Burner app. Erased the flash memory several times before burning the apps. Nothing happen on the screen. Looking at the code and monitoring the USB port, the IT8951 refuses to become ready to be programmed. (The WaitBusy() function returns a timeout status every time it is called).

I'm desperate. Any clue on something I can do?

robski

@turgu have you erased and loaded latest firmware to it via M5Burner?

turgu

@robski Yes, tried several applications. Burning is fine but nothing happen on screen. As indicated, the monitoring shown that the it8951 chip responsible of managing the screen refuses to become ready. As I'm a professional embedded developer, was also able to develop some code that manage properly the battery state, the buttons and the touchscreen. But the eInk screen controller refuses to become ready.

robski

@turgu shame, I do have myself one of M5Basic where lcd just stopped to work, all the rest works just fine except built in screen

turgu

@robski Was ready to buy a new M5PaperS3, but with this issue, I'm becoming less and less interested. I did built some software for the Inkplate eInk/esp32 based devices (an EPub reader and other stuff). This jeopardize my effort to port them to the M5Paper-ish devices.

turgu

@robski You can have a look at the EPub reader I wanted to port here

robski

@turgu sounds like you went in bit too deep in to display firmware maybe? - joking -

turgu

@robski At least on paper, the Inkplate devices are very similar in capabilities to the M5Paper. No reason to not being able to port the app, but hardware stability...

felmue

Hello @turgu

FWIW: in M5PaperS3 the eInk display is directly controlled by ESP32S3.

In M5Paper the GPIO WaitBusy() checks is GPIO27 which comes directly from IT8951 so I guess if the line never goes HIGH either IT8951 is not (properly) powered or defective.

Anyhow, have you tried to change the code to ignore the busy state of IT8951; maybe add some small delay instead.

BTW: I measured GPIO27 and when M5Paper is running it's being pulled up. I don't see a pull-up resistor in the schematics so I guess IT8951 is pulling it up (when not busy).

Thanks
Felix