atmo-monitor

KiCad design for a atmospheric measurement board. The MCU is a stm32f103cbt6. There are 2 main sensors. One is the PMS2007, which measures particulates, ie PM2.5. The other sensor is a BME680, which measures temperature, pressure, and organic compounds. The measurements are output on an E-Ink tri-color display.

This design is a continuation of a project that I did using a nucleo dev board and a perfboard pcb. The main goals used for this design:

- Use smd devices that I had already for the project, instead of a dev board
- Use an [Adafruit power supply breakout](https://www.adafruit.com/product/1944) that allows the use of a lithium battery. I didn't
want to implement this on the PCB for this project, and I don't have those types of devices on hand.
- Hand soldering for the pcb instead of my usual hot-plate reflow technique. This means
using 1206 size components instead of 0603, and SO footprint parts. This also helps with
the previous goal of using parts I had already, as my newer designs use TQFP footprints. I have successfully
hand soldered the smaller parts, but it is very tedious.

I was able to finish the design using those goals and the only part I needed to purchase was the adafruit power breakout. It is a 2-layer PCB that I have shared at Oshpark.

Changes

• Rev A Original

Firmware

Firmware

Connections to Segger JTAG

I have put test points on the board, so that pogo pins can be used to program the MCU.

jlink web page

**** 20 Pin connector for JTAG
                -------
    VTref      1|*   *|2 NC
    nTRST      3|*   *|4 GND
    TDI        5|*   *|6 GND
    TMS        7|*   *|8 GND
    TCK        9|*   *|10 GND
    RTCK      11|*   *|12 GND
    TDO       13|*   *|14 GND
    RESET     15|*   *|16 GND*
    DBGRQ     17|*   *|18 GND*
    5V Supply 19|*   *|20 GND*
                -------

From a 20pin JTAG connector, run wires to the following test pads to connect a debugger:

VTRef 1  <-> 3V3
SWDIO 7  <-> SWD
SWCLK 9  <-> SWC
RESET 15 <-> RST
GND   4  <-> GND

Running SEGGER JLink

Run the JLink GDB server via the following:

JLinkGDBServer -if SWD -device STM32F103CB

GDB can be connected via the following:

gdb-multiarch --command=jlink-stm32.gdb target/thumbv7m/debug/main

Running ocd

openocd -f interface/stlink-v3.cfg -f target/stm32f1x.cfg

Credits

as always, thanks for the good work

• Adafruit

License

Licensed under

• MIT license (LICENSE-MIT or http://opensource.org/licenses/MIT)