** 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.
This is a project I'm also submitting to the JLCPCB.com Holiday Contest!
- CH340G USB-to-TTL interface chip
- AMS1117-3v3 linear voltage regulator
- QMA7981 IMU in I2C mode
- STM32F030F4 - Arm M0 MCU
- 12Mhz External OSC
- Boot0 - CH340G's CTS (pin 9) (pulldown via 4.7K, but can be brought HIGH by CH340G by toggling CTS)
- 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 )
- PA2 - UART-TX (connects to CH340G's RX)
- PA3 - UART-RD (connects to CH340G's TX)
- 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)
- AD0 - Sets address. Routed to GND for 0. 0x12H
- INT2 - Interrupt signal output. Routed to PB1 on MCU
- TXD - To MCU RXD
- RXD - To MCU TXD
- CTS - To MCU BOOT0 for boot mode selector
- 12Mhz External OSC
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