1.4 KiB
1.4 KiB
Hardware
Current target: PineTime smartwatch.
PineTime is an open hardware smartwatch designed by Pine64.
It is capable of running fully custom firmware.
Core Specifications
Main hardware components include:
- Nordic nRF52832 MCU (ARM Cortex-M4F)
- 64 KB RAM
- 512 KB internal flash
- additional 4 MB SPI NOR flash for assets
- Bluetooth Low Energy support
The CPU runs at 64 MHz and includes a floating-point unit.
Display
PineTime includes:
- 1.3 inch IPS display
- resolution 240×240
- ST7789 display controller
- capacitive touchscreen controller
The display is connected through SPI.
Sensors
The device contains several sensors and peripherals:
- BMA421 accelerometer
- HRS3300 heart rate sensor
- vibration motor
- capacitive touchscreen
These are typically connected over I²C.
Battery
PineTime uses a small Li-Po battery around 170-180 mAh capacity.
Battery life depends heavily on firmware design and BLE usage.
Development Constraints
Important constraints for firmware design:
- very limited RAM (64 KB)
- limited internal flash (512 KB)
- firmware must run entirely from internal flash
- external flash cannot execute code
The external flash is mainly used for:
- fonts
- assets
- large UI resources.
Future Hardware Support
Vaka OS is designed primarily for PineTime.
Portability may be considered later but is not a primary goal during early development.