Hardware for controlling six VFD IV-17 and two VFD IV-1 tubes as clock (HH:MM:SS)
- efficient step-boost converter up to 50V
- multiplexing
- control syncronous addressable LEDs
- PWM control
- I²C interface
- connector for ESP (UART)
- time syncronisation line for every second
- octal buffer for PWM use seems do not works for dimming
- workaround: dimming solved by adding turn-off points in mulitplexing routine
- SPI is not suitable for controlling 20-bit shift register
- cut traces and wire up to another pins