> ## Documentation Index
> Fetch the complete documentation index at: https://docs.meowkit.cc/llms.txt
> Use this file to discover all available pages before exploring further.
# Schematics
Explore MeowKit’s hardware schematics and see how its modules are connected. They provide a detailed reference for hardware development, low-level debugging, and learning how MeowKit works at the hardware level.
***
# Main PCB
**Top Silkscreen**
Use a single-color MeowKit logo optimized for PCB printing. Keep the artwork simple and legible at the final printed size.
Maintain clear space around the logo and keep it away from pads, components, board edges, and other PCB features.
**Bottom Silkscreen**
Mark the designated 3M adhesive placement area on the bottom silkscreen using a dashed outline.
Add the label:
Keep the adhesive placement area free from components, vias, test points, and other features that may interfere with adhesive application or mechanical assembly.
**Manufacturing & Traceability**
The following manufacturing and traceability information shall be printed on the bottom silkscreen layer:
| **Field** | **Description** |
| :-------: | :------------------------------------: |
| MODEL | Product model identifier |
| REV | PCB hardware revision |
| DATE | Manufacturing date |
| BATCH | Production batch number |
| SN | Serial number / barcode / QR code area |
| QC | Quality control inspection mark |
Recommended Layout
```Plain theme={null}
MK-S3-KS-1500 REV 5.0
AUTHOR: wangte
DATE: 2026-03-28
BATCH: A01
SN:
QC:
```
***
## Main blocks overview
Every block is shown in detail as a separate document below.
***
## Power
The device uses the **AXP173 PMIC** as the central power management controller, integrating USB power input, Li-ion battery charging, power-path switching, voltage regulation, and system monitoring.
The power system automatically manages energy flow between **USB VBUS and battery power**, providing stable power rails for the **ESP32-S3, sensors, and peripheral devices**.
Through the **I²C control interface**, the main processor can monitor power status, configure charging parameters, and respond to power events through interrupt signals.
**Power Initialization Notice**
During system startup, the AXP173 requires a short initialization period to complete internal power sequencing and stabilize all output rails.
Although the I²C interface may become available during this stage, the power management system may still be completing internal configuration.
To ensure reliable startup, it is recommended to use the PWROK signal to control the MCU reset sequence. The processor should begin execution only after all required power rails have reached a stable operating state.
## MCU
## USB
## Display
## Buttons & Joystick
## Audio
## Storage
## Sensor
## LED
## RTC
## IO Expander
## GPIO
A 1×16 pin (2.54 mm) DuPont female expansion header provides native support for SPI, I²C, and general-purpose GPIO interfaces, freeing the device from single-function limitations.
It can become anything you choose to define — a retro camera, digital level, tachometer, distance meter, Morse code transmitter/receiver, and much more.
***
# NFC
