Table of Contents
Reverse engineering the SMA-Q2/SMA-Time smartwatch
by emeryth (emeryth at hackerspace.pl)
Intro
SMA Q2 also known as SMA TIME is a Chinese smartwatch similar in design and features to the Pebble Time.
Featuring a color Memory LCD, heart rate sensor and a NRF52832 Bluetooth SoC to drive it all.
All the documents and interesting things are uploaded here: https://owncloud.hackerspace.pl/index.php/s/1bqTRwMI8XKXGKL
Hardware
Chips
| IC | Description | Datasheet |
|---|---|---|
| NRF52832-QFAAB0 | Main SoC | |
| LP2985 (?) | 3.3V LDO for everything | |
| LP2985 (?) | 3.3V LDO for heart rate sensor module | |
| BQ24086 (?) | Battery charger | |
| KX022-1020 | 3-Axis acccelerometer | |
| PAH8002 | Heart rate sensor | |
| GD25Q16C (?) | 16Mbit SPI flash | |
| LPM013M126A (?) | 176×176 Japan Display Color memory LCD |
MCU Pinout
| Pin | Description |
|---|---|
| P0.02 | LCD SCLK |
| P0.03 | LCD SI |
| P0.05 | LCD SCS |
| P0.06 | LCD EXTCOMIN |
| P0.07 | LCD DISP |
| P0.04 | Battery voltage measurement (x0.25 divider) |
| P0.08 | BACKLIGHT ON |
| P0.09 | BUTTON BACK |
| P0.27 | BUTTON UP |
| P0.28 | BUTTON OK |
| P0.29 | BUTTON DOWN |
| P0.11 | FLASH MISO |
| P0.12 | FLASH CS |
| P0.13 | FLASH MOSI |
| P0.14 | FLASH CLK |
| P0.25 | UART RX |
| P0.26 | UART TX |
| P0.30 | VIBRATOR ON |
| P0.15 | ACCEL INT ? |
| P0.16 | ACCEL POWER |
| P0.17 | ACCEL SDA |
| P0.18 | ACCEL SCL |
| P0.19 | HRM SDA |
| P0.20 | HRM SCL |
| P0.22 | HRM INT? |
| P0.10 | HRM RESET? |
| P0.31 | HRM POWER ON |