Do not perform redundant reset on ST7789 displays#2475
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JosiahWI wants to merge 1 commit intomeshcore-dev:devfrom
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Do not perform redundant reset on ST7789 displays#2475JosiahWI wants to merge 1 commit intomeshcore-dev:devfrom
JosiahWI wants to merge 1 commit intomeshcore-dev:devfrom
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The `::init` method in the Adafruit ST7789 library is responsible to initialize the device. This includes performing a reset, which can be found in the Adafruit source for `Adafruit_SPITFT`. Before this change, MeshCore performed its own ST7789 display reset sequence, which consisted of three steps. * Pull reset low * Wait 10ms * Pull reset high Importantly, there was no fixed delay after pulling reset high. The ST7789 driver requires a delay (T<sub>RT</sub>) of 5ms in Sleep In Mode and 120ms in Sleep Out Mode before it will properly receive commands. When `Adafruit_SPITFT` resets the device after MeshCore has already reset it, the mandatory time may not have elapsed, leading to strange behavior. In the author's case, this issue caused the initial `fillScreen` to fail, such that the display showed an uninitialized framebuffer. This removes the MeshCore delay, leaving the responsibility of reset to `Adafruit_SPITFT`, where they have the correct delays in place with extra safety margin. The change was briefly tested by Josiah VanderZee and Ben Zignego on a custom hardware build using an nRF52840 Dongle and an Adafruit 4311 TFT display. The user button seemed to behave strangely, but the display looked correct.
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The
::initmethod in the Adafruit ST7789 library is responsible to initialize the device. This includes performing a reset, which can be found in the Adafruit source forAdafruit_SPITFT.Before this change, MeshCore performed its own ST7789 display reset sequence, which consisted of three steps.
Importantly, there was no fixed delay after pulling reset high. The ST7789 driver requires a delay (TRT) of 5ms in Sleep In Mode and 120ms in Sleep Out Mode before it will properly receive commands. When
Adafruit_SPITFTresets the device after MeshCore has already reset it, the mandatory time may not have elapsed, leading to strange behavior. In the author's case, this issue caused the initialfillScreento fail, such that the display showed an uninitialized framebuffer.This removes the MeshCore delay, leaving the responsibility of reset to
Adafruit_SPITFT, where they have the correct delays in place with extra safety margin. The change was briefly tested by Josiah VanderZee and Ben Zignego on a custom hardware build using an nRF52840 Dongle and an Adafruit 4311 TFT display. The user button seemed to behave strangely, but the display looked correct.