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    M5Paper EPD power consumption

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    • felmueF
      felmue
      last edited by

      Hello @tatar-andrei

      understood. I am very interested in what you will discover in that regard as I have very little experience so far with EPDs.

      I guess you have seen the documents @loboris shared here.

      Thanks
      Felix

      GPIO translation table M5Stack / M5Core2
      Information about various M5Stack products.
      Code examples

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      • T
        tatar-andrei
        last edited by

        @tatar-andrei said in M5Paper EPD power consumption:

        169 mA - with the default app
        93 mA - with EPD power disabled

        So it seems that sending IT8951 in standby mode results in

        • 75mA power consumption.

        Which is a bit weird given that EPD power disabled (GPIO 23) takes about 93mA... Maybe it sources some current from the GPIO pins?

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        • S
          sok @tatar-andrei
          last edited by

          @tatar-andrei said in M5Paper EPD power consumption:

          When the main MOSFET is powered down, the only way to wake up the device automatically is via the RTC chip (alarm or timer interrupt) and without any previous state (unless written to FLASH/SD). This is a good way of shutting down the device completely.

          Hello, I have a question about this - can we power down this main MOSFET during ESP32 program? ( as I understand, you about FET1 between VBAT_IN and VBAT on the schematic which powered step-up to 5V, which powered stepdown to 3.3V which powered ESP32)

          It's hard for me to answer this question myself when seeing such schematic - it's really burning my mind.

          If it's possible, we have EEPROM to use it like RTC, and lots of pseudo-low-power projects can be done on M5Paper.

          1 Reply Last reply Reply Quote 0
          • felmueF
            felmue
            last edited by

            Hello @sok

            you should be able to power down by calling M5.shutdown().

            Thanks
            Felix

            GPIO translation table M5Stack / M5Core2
            Information about various M5Stack products.
            Code examples

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            • S
              sok
              last edited by

              Hello @felmue

              Thanks for showing the start point of the search. (I go to Github to see the realization of this function and also to see how here working with RTC alarm, gotten PINs, and schematic becomes 100 times clear for me) I can answer my question myself.

              At normal POWER_OFF state - PWR_EN point in schematic setted to HIGH (VBAT_IN -> R35 -> D10 - >C94), it,s HIGH state block power from VBAT_IN -> VBAT use FET1 to close this path.

              When we push button(and hold it for some seconds) we open path PWR_EN ->D10 -> KEY_PUSH -> GND, which set PWR_EN to LOW and open path VBAT_IN -> FET1 -> VBAT. VBAT powered chain of DC, and power our ESP32. After start ESP32 push the virtual button(FET2) using PS_ON, which opens path PWR_EN->FET2->GND, and stable hold power to DC(and sensors and esp32), and now we can realese push button, and all will still work.

              When we set ALARM to RTC PCF8563, and then release FET2, we allow to PWR_EN become HIGH again through 100k resistor R35. When it becomes HIGH, it automatically powers off our ESP32, DC-DC, and sensors. But RTC PCF8563 will still work cause it powered over VBAT_IN.

              When alarm time becomes - PWR_EN setted low through path PWR_EN -> D7 -> RTC_ALARM - >INT - > GND. Which allow ESP32 to start again.

              Thanks!

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              • T
                tatar-andrei
                last edited by

                Yes, it's pretty straight forward to power down the ESP32 completely and the power draw in that state is about 1.5 uA.

                I did play around more with power down states and I managed to get a light sleep mode with fast wakeup from touch at around ~9mA.

                I didn't get to play around with doze mode yet. I hope to get 1-2 mA when touch is in doze (gesture?) mode and ESP32 in deep sleep.

                C J 2 Replies Last reply Reply Quote 0
                • B
                  bricox
                  last edited by

                  Hello @tatar-andrei,
                  I am also going to use a power supply to continue analyzing the consumption of the various components because IT consumes a lot.
                  Can we turn it off with a mos then turn it on again?
                  Will it be able to reset itself without the ESP32 sending it an initialization sequence?
                  I will study this ...
                  SYL

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                  • C
                    careyer @tatar-andrei
                    last edited by

                    @tatar-andrei said in M5Paper EPD power consumption:

                    1.5 uA.

                    @tatar-andrei could ou please share how you managed to get down to 1.5 uA? Is the ESP32 still in deepsleep in this state and can be woken up via RTC/timer or is the unit completley turned off and needs some user-interaction in order to wake up?
                    (I have no M5paper yet and want to find out if it is suitable for my project).

                    I am highly interested in how much amperage is drawn in deepsleep with the RTC configured to wake the ESP32 up in regular intervals. Could you please test this? Thanks man!

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                    • T
                      tatar-andrei
                      last edited by

                      could you please share how you managed to get down to 1.5 uA?

                      Turn off the mosfet that powers the ESP32 (M5.disableMainPower(); - https://github.com/m5stack/M5EPD/blob/main/src/M5EPD.h#L49). In this mode everything but the external RTC (BM8563) is powered off.

                      In order to wake up from this mode you either need to press the button on the side, or use the external RTC interrupt.
                      The M5 lib contains a few functions that do exactly this (setup the external RTC to wakeup the board in a few seconds): https://github.com/m5stack/M5EPD/blob/main/src/M5EPD.cpp#L133

                      B 2 Replies Last reply Reply Quote 0
                      • B
                        bricox
                        last edited by

                        Hello @tatar-andrei,

                        With a supply of 4.2V, U(R35)=11mV, equivalent to 1.1µA for RTC and zener D11current.

                        Equivalence names table
                        0_1609361186835_5027511b-cee9-4100-a03b-8bcdc3b8b6f9-image.png

                        There is inversion between Left and Right, why not having simply called the buttons Top and Bottom?

                        SYL

                        B 1 Reply Last reply Reply Quote 0
                        • B
                          bricox
                          last edited by

                          Hello,

                          i also made a fisrst compact schema to facilitate understanding

                          0_1609362387445_6bedbef9-cc33-48d4-96bd-970bd15532db-image.png

                          SYL

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                          • B
                            bricox
                            last edited by

                            Hello,

                            If the repository is facing the wheel,

                            0_1609397793398_abc6142e-f0dd-4827-9167-49a0b347486c-image.png

                            "code source" is true, "SCH-name" is false

                            0_1609397946546_5e5d7b82-4846-499d-8f3b-096794dee6ba-image.png

                            SYL

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                            • B
                              bricox
                              last edited by

                              Hello,
                              I completed the schema with VUSB_IN, VSYS and OR fonction with D9,D12

                              0_1609408092751_1b84713e-842f-4d87-af32-590bbc36dd6f-image.png

                              SYL

                              1 Reply Last reply Reply Quote 1
                              • MattMM
                                MattM
                                last edited by

                                I just received my M5Paper and I can not get a 100% charge? The power consumption also seems high. I am only observing the battery level indicator relative to device use. Is there a problem with the firmware? Is the Wifi function draining the battery prematurely?

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                                • B
                                  bricox
                                  last edited by

                                  Hello,
                                  On mine, the maxi level indicator of charge is 86% corresponding to 4.18V
                                  I measured USB current with the program "Factory test" and a serial USB device named "UT25".
                                  The value is 131 mA, without interraction.
                                  I also wrote personal comments about all GPIOs (in french, my native language):
                                  0_1609540042308_d0d7e2f2-2754-4c13-bdb0-eac50a0d8423-image.png
                                  All GPIOs are represented (except non-existent ones : 20, 24, 28, 29, 30, 31)
                                  SYL

                                  1 Reply Last reply Reply Quote 1
                                  • R
                                    ricecake @tatar-andrei
                                    last edited by

                                    @tatar-andrei
                                    Hello!

                                    I was wondering if you could provide some reference for how you got into doze mode/wake on touch? I've been trying for a few days now and for the life of me can't seem to make any meaningful progress.

                                    1 Reply Last reply Reply Quote 0
                                    • T
                                      tatar-andrei
                                      last edited by

                                      You can check other GT9xx drivers like (http://read.pudn.com/downloads710/sourcecode/embedded/2849392/gt9xx.c__.htm).

                                      I will need to play some more with it. I'll probably post here a link to my repo once I push the code.

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                                      • B
                                        bricox @bricox
                                        last edited by

                                        Hello,
                                        If you want to measure RTC and zener D11 current, i indicate the PCB resistors positions
                                        0_1609839826079_87253ca3-b5c9-49a3-a940-755467abbc04-image.png
                                        SYL

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                                        • B
                                          bricox @tatar-andrei
                                          last edited by

                                          Hello,
                                          As I was saying five days ago,
                                          "I measured USB current with the program "Factory test" and a serial USB device named "UT25".
                                          The value is 131 mA, without interraction."
                                          Since then, I have measured the current according to the different programs :
                                          0_1609964987251_7f2faa65-cde9-482f-afb7-a5bb3f48ebc1-image.png
                                          The cause of this excess consumption is IT8951.
                                          An alternative to this component is the 74HC4094D, 8-stage shift-and-store bus register, used as IO extander.
                                          A competitor with the same display consumes 65 mA, i measured to.
                                          SYL

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                                          • B
                                            bricox @tatar-andrei
                                            last edited by

                                            Hello,
                                            Here is Shift Register schema, the brend is Nexperia.
                                            0_1609978353293_046fa671-5c10-4313-ad80-216963318452-image.png
                                            SYL

                                            1 Reply Last reply Reply Quote 0
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