Wing's XMAS Ornament

** ISSUE - Design Seems To produce non-working unit. Investigating... **

• Something for the holidays.
• Made using SMT/SMD components so most/all parts on one side.
• Added header pins on revrse side for adding batteries or different UART(s).
• Added USB-A PCB top to allow plugging into a laptop or computer USB port or to power with a USB-A extension cable.

JLCPCB Holiday Contest Entry

This is a project I'm also submitting to the JLCPCB.com Holiday Contest!

• http://www.jlcpcb.com

Hardware

Components

• CH340G USB-to-TTL interface chip
• AMS1117-3v3 linear voltage regulator
• QMA7981 IMU in I2C mode
• STM32F030F4 - Arm M0 MCU

STM32

• 12Mhz External OSC
• Boot0 - CH340G's CTS (pin 9) (pulldown via 4.7K, but can be brought HIGH by CH340G by toggling CTS)

I2C

• PA9 - I2C SCL (connects to QMA7981's SCL)
• PA10 - I2C SDA (connects to QMA7981's SDX)
• PB1 - Motion Interrupt Signal ( connects to QMA7981's INT2 )

UART

• PA2 - UART-TX (connects to CH340G's RX)
• PA3 - UART-RD (connects to CH340G's TX)

LED Driving Lines

• PA0 - A (CharliePlexed LED Lines)
• PA1 - B (CharliePlexed LED Lines)
• PA4 - C (CharliePlexed LED Lines)
• PA5 - D (CharliePlexed LED Lines)
• PA6 - E (CharliePlexed LED Lines)
• PA7 - F (CharliePlexed LED Lines)
• PA13 - G (CharliePlexed LED Lines)
• PA14 - H (CharliePlexed LED Lines)

QMA7981

• AD0 - Sets address. Routed to GND for 0. 0x12H
• INT2 - Interrupt signal output. Routed to PB1 on MCU

CH340G

• TXD - To MCU RXD
• RXD - To MCU TXD
• CTS - To MCU BOOT0 for boot mode selector
• 12Mhz External OSC

Software

Building & Installing Arduino Code

The code is setup as a platformio project. To build:

# To compile/build
pio run

# To upload (Note, assumes serial upload)
pio run --target=upload