Lup Yuen Lee 李立源

Now coding the Stack Touch Panel Driver for Apache RTOS 😬 ... Same I2C Touch Panel as PineTime

github.com/lupyuen/cst816s-nut

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Lup Yuen Lee 李立源

Driver for Cypress MBR3108 Touch Controller looks structurally similar to Stack's CST816S ... So we copy-n-paste into our CST816S Driver

github.com/lupyuen/cst816s-nut

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Lup Yuen Lee 李立源

Stack's CST816S Touch Panel is a peculiar I2C Device ... It won't respond to I2C Scan unless we tap the screen and wake it up!

github.com/lupyuen/cst816s-nut

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Lup Yuen Lee 李立源

Stack's Touch Panel triggers a GPIO Interrupt when we tap the screen ... Here's how we handle the GPIO Interrupt in

github.com/lupyuen/cst816s-nut

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Lup Yuen Lee 李立源

Tapping the screen on Stack ... Correctly triggers a GPIO Interrupt on RTOS! 🎉

github.com/lupyuen/cst816s-nut

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Lup Yuen Lee 李立源

Apache RTOS has a standard data format for Touch Input ... Let's implement this for Stack

github.com/lupyuen/cst816s-nut

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Lup Yuen Lee 李立源

Here's how our Driver reads the Touch Data on Stack

github.com/lupyuen/cst816s-nut

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Lup Yuen Lee 李立源

Our Driver for Stack's Touch Panel returns 4 possible states: Touch Down vs Touch Up, Valid vs Invalid

github.com/lupyuen/cst816s-nut

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Lup Yuen Lee 李立源

Driver for Stack 's Touch Panel responds correctly to touch! 🎉 The touched coordinates are rotated sideways ... But we can fix that later in the ST7789 Display

github.com/lupyuen/cst816s-nut

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Lup Yuen Lee 李立源

Touch Screen for Stack feels laggy on Apache RTOS right now ... 2 things we can fix: 1️⃣ Increase SPI Frequency 2️⃣ Switch to SPI DMA eventually

youtube.com/shorts/2Nzjrlp5lcE

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Lup Yuen Lee 李立源

LVGL Test App calls read() repeatedly on Stack's Touch Panel Driver to get Touch Data ... But it should call poll() instead to block on Touch Data 🤔

github.com/lupyuen/cst816s-nut

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Lup Yuen Lee 李立源
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Touch Coordinates read over I2C from Stack Touch Panel ... Are returned unchanged to the LVGL Test App as a Touch Down Event

github.com/lupyuen/cst816s-nut

· · Tusky · 1 · 0 · 2
Lup Yuen Lee 李立源

But for Touch Up Events the Touch Coordinates are invalid ... Our Stack driver patches the Touch Coordinates with the data from the last Touch Down Event

github.com/lupyuen/cst816s-nut

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Lup Yuen Lee 李立源

Our Driver for Stack Touch Panel won't return any valid Touch Data unless we enable I2C Logging ... Could be an I2C Timing Issue or Race Condition 🤔

github.com/lupyuen/cst816s-nut

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Lup Yuen Lee 李立源

Upcoming fixes for Apache RTOS on Stack 🤔

github.com/lupyuen/cst816s-nut

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Lup Yuen Lee 李立源

Apache RTOS on Stack now supports Touch Screen ... Works OK with LoRaWAN too! 👍

github.com/lupyuen/incubator-n

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Lup Yuen Lee 李立源

Building the Touch Panel Driver for Apache RTOS on Stack @PINE64 ... All shall be explained in this article

lupyuen.github.io/articles/tou

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Lup Yuen Lee 李立源

Stack's CST816S Touch Panel seems elusive ... Thanks to PineTime we know everything now!

lupyuen.github.io/articles/tou

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Lup Yuen Lee 李立源

Connecting Stack's CST816S Touch Panel to Apache RTOS

lupyuen.github.io/articles/tou

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Lup Yuen Lee 李立源

What's inside a Touchscreen Driver

lupyuen.github.io/articles/tou

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Lup Yuen Lee 李立源

Apache RTOS defines a standard data format for Touch Data

lupyuen.github.io/articles/tou

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Lup Yuen Lee 李立源

How our App reads the touched coordinates from Stack's Touch Panel

lupyuen.github.io/articles/tou

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Lup Yuen Lee 李立源

Here's how we load the Touch Panel Driver on Stack

lupyuen.github.io/articles/tou

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Lup Yuen Lee 李立源

Initialising the Touch Panel Driver on Stack

lupyuen.github.io/articles/tou

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Lup Yuen Lee 李立源

Stack's Touch Panel will trigger a GPIO Interrupt when touched ... Here's how we handle the interrupt on Apache RTOS

lupyuen.github.io/articles/tou

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Lup Yuen Lee 李立源

Testing the GPIO Interrupt that's triggered ... When we tap Stack's CST816S Touch Panel

lupyuen.github.io/articles/tou

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Lup Yuen Lee 李立源

Here's the Touch Data returned by Stack's CST816S Touch Panel

lupyuen.github.io/articles/tou

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Lup Yuen Lee 李立源

Reading the Touch Data from Stack's CST816S Touch Panel

lupyuen.github.io/articles/tou

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Lup Yuen Lee 李立源

We prevent unnecessary I2C Reads in Stack's Touch Panel Driver ... By checking whether the screen has been touched

lupyuen.github.io/articles/tou

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Lup Yuen Lee 李立源

Here's how we test our Touch Panel Driver for Stack on Apache RTOS

lupyuen.github.io/articles/tou

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Lup Yuen Lee 李立源

Our App reads the data from Stack's Touch Panel

lupyuen.github.io/articles/tou

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