Optimal wiring NULA DeepSleep ESP32-S3 <-> Touchscreen and 2x SHTC3?

TECHNICAL SUPPORT Everything else
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1

I’m new in the sense of wire MUC components together :wink:

I think I’ve sort of grasped the basics.

Currently i’m work on my WIP: Display Basement Ventilation and concentrate on the ESP32 < - > Touchscreen part and start with:

| ESP32S3 Pin         | ESP32S3 GPIO | TFT Pin | Notes                         |
|---------------------|--------------|---------|-------------------------------|
| VCC (5 V via USB-C) | VCC          | VCC     | TFT supports both: 3.3V or 5V |
| GND                 | GND          | GND     | Ground                        |
| -                   | -            | PEN     | Touch interrupt (not used)    |
| -                   | -            | RST     | Reset (not used)              |
| GPIO (Digital)      | GPIO 8       | DC      | Data/Command                  |
| GPIO (PWM)          | GPIO 21      | BL      | Brightness control            |
| SPI SCK             | GPIO 12      | CLK     | Clock line                    |
| SPI MISO            | GPIO 13      | DO      | MISO, SPI Data Input          |
| SPI MOSI            | GPIO 11      | DI      | MOSI, SPI Data Output         |
| GPIO (Digital)      | GPIO 10      | CSL     | Chip Select for TFT           |
| GPIO (Digital)      | GPIO 9       | CST     | Chip Select for Touch         |
| -                   | -            | BSY     | Busy Touchscreen (not used)   |
| -                   | -            | OE      | Output Enable (not used)      |
| 3V3                 | -            | -       | 3,3V unused                   |

Any suggestions to make this better?

I think it would also be helpful to have official instructions or guidelines on how to connect these two components.

2

Hi @jedie ,

thanks for your question! I had to take a bit of time to research this. The wiring table looks good, the SPI pins on ESP32-S3 are correct and as marked on our pinout so there should be no surprise. Does this setup have any problems? There isnt’ really an official way to connect the development board and an external SPI display as it’s a general thing and the implementation of these is done on a case by case basis except the standard SPI pins. Do you have any specific issues with this not working or?

3

Year, i know that there is no standard way for this. My question is, if there is any best-practice wiring for these two components?

I think it would be helpful for others if you offer a “official” proposal.

A follow-up question would be: How to connect two SHTC3 on one ESP32 ?

4

Hey @jedie,

unfortunately, providing an “official” best-practice wiring guide for every possible component combination is something we’re not really able to do due to the large number of permutations between different microcontrollers and external components. For our own 2.4 lcd and our old Dasduino CONNECTPLUS board we have an example in our docs but it’s not very relevant here. But I must say it’s a totally valid feedback that we should have more connecting diagrams and examples. It’s also something which could be resolved with a “project wizard” app that helps you generate wiring suggestions based on your specific components!

As for connecting two SHTC3 sensors to a single ESP32, this is unfortunately not straightforward. The SHTC3 has a fixed I2C address of 0x70 with no way to change it (no address jumpers), meaning you can’t simply put two on the same I²C bus without a conflict.

You have two practical options:

  1. I2C Multiplexer - Use something like our TCA9548A I²C Multiplexer breakout, which lets you connect multiple same-address devices by routing them through separate channels.
  2. Secondary microcontroller as a bridge, a small, inexpensive additional MCU can act as a bridge between the second SHTC3 and your ESP32, handling the communication separately.