Not always full refresh for waveshare_epaper on wake-up

[Richhoef]

Component name

waveshare_epaper

Link to component documentation on our website

https://esphome.io/components/display/waveshare_epaper/

Describe the enhancement

Currently, at least with the 7.50inv2p, the display does a full update everytime it starts up. So also after a deep sleep, a full refresh is done. This makes the display flicker quite often, while it is not nessecary every time. I have fixed this with a custom component that manipulates the at_update_ value (see added files).

In my yaml, I have a persistant global variable. Before the display update, immediately after wakeup, I do:

      - lambda: |-
            /* Persistant refresh */
            auto *display = (waveshare_persistent_refresh::WavesharePersistentRefresh *)id(epaper_display);
            display->set_persistent_counter(id(persistent_at_update_counter));

Then after the update I do:

      - lambda: |-
          auto *display = (waveshare_persistent_refresh::WavesharePersistentRefresh *)id(epaper_display);
          id(persistent_at_update_counter) = display->get_persistent_counter();

So a way to do this is to have a variable given to the component which is persistant, but another way is to have an option that prevents the full update the first time in the full refresh cycle (or have full_update_every: 0 never doing a full refresh and let the user be responsible to do a full update every few times, by doing something like:

      - lambda: |-
          auto *display = (waveshare_persistent_refresh::WavesharePersistentRefresh *)id(epaper_display);
          id(persistent_at_update_counter) = display->get_persistent_counter();
          if (id(persistent_at_update_counter) == 0) {
            display->force_full_refresh();
          } else {
            display->force_partial_refresh();
          }

Python file:
display.py

custom header file:

#pragma once

#include "esphome/core/component.h"
#include "esphome/core/log.h"
#include <esphome/components/waveshare_epaper/waveshare_epaper.h>

namespace esphome {
namespace waveshare_persistent_refresh {

static const char *const TAG = "waveshare.persistent";

class WavesharePersistentRefresh : public waveshare_epaper::WaveshareEPaper7P5InV2P {
 public:
  void set_persistent_counter(int counter) {
    // Restore at_update_ from persistent storage before display update
    this->at_update_ = counter % this->full_update_every_;
    ESP_LOGI(TAG, "Restored at_update_ from persistent storage: %d (full_update_every=%d)",
             this->at_update_, this->full_update_every_);
  }

  int get_persistent_counter() {
    // Return current at_update_ value to save persistently
    ESP_LOGI(TAG, "Saving at_update_ to persistent storage: %d", this->at_update_);
    return this->at_update_;
  }

  void display() override {
    ESP_LOGI(TAG, "Display update starting - at_update_=%d, full_update_every_=%d",
             this->at_update_, this->full_update_every_);

    // Determine what type of refresh will happen
    if (this->full_update_every_ == 1) {
      ESP_LOGI(TAG, ">>> FULL REFRESH (forced by full_update_every=1)");
    } else if (this->at_update_ == 0) {
      ESP_LOGI(TAG, ">>> FAST FULL REFRESH (at_update=0, first in cycle)");
    } else {
      ESP_LOGI(TAG, ">>> PARTIAL REFRESH (at_update=%d)", this->at_update_);
    }

    // Call parent display method which will update at_update_
    waveshare_epaper::WaveshareEPaper7P5InV2P::display();

    ESP_LOGI(TAG, "Display update complete - at_update_ is now %d", this->at_update_);
  }

  void force_partial_refresh() {
    // Force next refresh to be partial by setting at_update_ > 0
    if (this->at_update_ == 0) {
      this->at_update_ = 1;
      ESP_LOGI(TAG, "Forced at_update_ to 1 for partial refresh");
    }
  }

  void force_full_refresh() {
    // Force next refresh to be full by setting at_update_ = 0
    this->at_update_ = 0;
    ESP_LOGI(TAG, "Forced at_update_ to 0 for full refresh");
  }

  uint32_t get_full_update_every() {
    return this->full_update_every_;
  }
};

}  // namespace waveshare_persistent_refresh
}  // namespace esphome

Use cases

This would minimize the distracting flickering from every wakeup cycle to only every X wakeup cycles.

Anything else?

No response

[github-actions[bot]]

🏷️ I've automatically added the component: waveshare_epaper label to help categorize this feature request.