Magic Notebook Project Specification
Purpose
Custom low-power 4-layer PCB backing board for an A5 smart notebook. Captures a 4-wire resistive touch sheet and sends touch data over Wi-Fi.
Core Architecture
- MCU: ESP32-S3-WROOM-1-N16R8 module on 3.3 V.
- Power: USB-C VBUS charges a 1-cell LiPo through a single-cell charger; protected battery feeds an AP2112K-3.3 LDO.
- Touch: TSC2007 resistive touch controller over I2C, with PENIRQ wake interrupt.
- Analog: OPA2333 powered from 3.3 V and wired as a unity-gain auxiliary buffer into TSC2007 AUX.
- Sensor input: 4-pin FPC for X+, X-, Y+, Y-.
Key Design Choices / Caveats
- Exact SGM4056 was not available in the library; SGM40567 was used as the SMD single-cell charger candidate. It is WLCSP and supports resistor-set charge current.
- SGM40567 IREF resistor selected as 36.5 kΩ for approximately 500 mA target charge current.
- TSC2007 normally computes pressure from X/Y measurements; the OPA2333 auxiliary buffer is connected to AUX as an optional buffered analog input rather than being required for basic 4-wire touch operation.
- ESP32-S3 GPIO8=SDA, GPIO9=SCL, GPIO10=PENIRQ, GPIO0=BOOT, EN=reset/power enable.
Layout Requirements
- 4-layer PCB.
- ESP32 antenna at board edge with full antenna keepout on all copper layers.
- USB ESD close to USB-C connector.
- Keep FPC-to-TSC2007/OPA2333 analog traces short and away from USB and Wi-Fi antenna area.