"polylab" DIY Microchip AVR® Dx32-Series Development-Board

Hardware:

• 2 layer PCB designed with KiCad 7 EDA.
• KiCad learned with ûdemy course
• PCB manufactured by Aisler
• proprietary form factor: 1/2 credit card size ( 53.98 x 42.8 mm)
• proprietary pinout (2 x 19pin)

MCU:

Microchip AVR64DD32 (QFP32 socket). Replacement or successor for the old ATmega328P?

• 8-bit MCUs: Still Thriving After 50 Years
• If you're a fan of ATmega, try AVR Dx
• AVR® DD Product Family Overview
• AVR Peripheral Deep Dive
• https://www.arduino.cc/en/software Arduino IDE
• https://github.com/SpenceKonde/DxCore Arduino support for the AVR DA, DB-series and DD-series
• SerialUPDI programmer Flashing Optiboot bootloader ok with the above versions

Flashing Optiboot Bootloader via UPDI Target Header.

mikroBUS™:

• https://www.mikroe.com/mikrobus
• https://www.mikroe.com/click
• Sensirion & mikroBUS™ , ETHzürich & mikroBUS™ , Microchip & mikroBUS™ , u-blox & mikroBUS™

First Experimental Tests based on Arduino IDE Examples for Custom Libraries

MCCI LoRaWAN LMIC-node connected to TTN ... tested with Arduino IDE 2.3.4 and DxCore Version 1.5.11

Graphics with SPI TFT displays on mikroBUS™ socket ...
Adafruit example sketch graphicstest.ino with ST7735 and ST7789 library. Initialize ST7789 240x240 with tft.init(240, 240, SPI_MODE3) https://tigoe.github.io/display-examples

u-blox PAM-7Q GPS Module added (--> TTN-Mapping walk) ...

needs to be synced with RTC or GPS / PoLoLu Stepper Motor Driver on mikroBUS™ Modul / DHT22 Temperature/Humidity Sensor (incl. Payload Encoding / Decoding) / Servo Sweep (#include <Servo_DxCore.h>)

Test mikroBUS CO2 click board with Sensirion STC31-sensor on my "polylab" Development-Board with mikroBUS socket. Sketches with Sensirion-Arduino library and SparkFun Arduino Library for STC3x sensor. CO2 gas for testing produced with baking soda and water.

First successful TTN test with Grove Wio E5 LoRa-E5 Arduino Library from Sylvain Montagny.
https://github.com/SylvainMontagny/LoRaE5
Successful upload of DHT22 sensor data.
Successful switching LED_BUILTIN according to PayloadDown value (0x00/0x01)

Next project: mikroBUS Board with Seeed Studio Grove Wio-E5 Module.

Peripheral Connectors

• 2 x 19 pin male pinheader with Arduino/MKR- Adafruit/Feather- like pinout
• mikroBUS™ socket
• 2 x Grove connector (I2C & UART)
• 2 x 4-pin header (female) with Grove Digital/Analog pinout
• 1 x Qwiic® connector
• MicroUSB (CH340N USB to UART converter)

Power Supply Connectors

• Barrel Jack 7-12V DC, 3.5*1.3mm ( to 5V with AMS1117-5.0)
• MicroUSB (5V to 3V3 with AP2112K-3.3)
• JST PH 2.0 for Single LiPo cell (MCP73831 charge controller)
• 6-pin UPDI-target-header (male)

This board is still a WiP! There is a list with many changes, improvements and extensionss for the next version.

DIY mikroBUS™ Socket compatibles Hardware-Modules:

Modules for RFM95W / Seeed Studio Grove Wio-E5 / Seeed Studio Wio-SX1262 (prototype)

8 daisy-chained NeoPixel / LED's on all pins for mikroBUS™ socket testing

PoLoLu Stepper Motor Driver

"polylab"-Prototyping Ecosystem:

PCB on doubler board / PCB on breadboard / PCB stacked / powered with DC (9V battery), USB or LiPo

"polylab"-Custom Boards:

made with regular protoboards and pinheaders

Modelling a case with OpenSCAD (done) (https://openscad.org)

Planned:

Low Power / Sleep Mode
Energy Harvesting

Work in progress: mikroBUS™ Board with Seeed Studio Wio-SX1262 Module.

Wio-SX1262 Wireless Module
XIAO ESP32S3 & Wio-SX1262 Kit for Meshtastic & LoRa
Wio-SX1262 for XIAO

Test environment:

"polylab" Triple-Board with "polylab" Dev.-Board, Wio-SX1262 Extension Board and Bosch BME280 Sensor/SSD1306 OLED Display Board.

• Successful LoRaWAN test with Arduino RadioLib library on my DIY Microchip AVR64DD32 board with Wio-SX1262 Module and Arduino DXcore.

  23:29:08 ->
  23:29:08 -> Setup ...
  23:29:08 -> Initialise the radio
  23:29:08 -> Join ('login') the LoRaWAN Network
  23:29:14 -> Ready!
  23:29:14 ->
  23:29:14 -> Sending uplink
  23:29:19 -> Received a downlink
  23:29:19 -> Next uplink in 300 seconds
  

  Disadvantage of Arduino RadioLib library: Example Sketch uses 63572 bytes (97%) of program storage space. Maximum is 65024 bytes. Comment of the maintainer of the RadioLib library: Unfortunately, small footprint was not one of the design goals of this library!

• The Arduino MCCI LoRaWAN LMIC library supports the SX1262 since Verion 5. Based on the configuration suggestion of Tristan Webber my Wio-SX1262 example sketch is running fine! mcci-catena/arduino-lmic#982

  18:42:31.536 -> Starting
  18:42:31.536 ->
  18:42:31.715 -> Sensor Bosch BME280:
  18:42:31.715 -> Temperature = 23.53 °C
  18:42:31.715 -> Humidity = 38.00 %
  18:42:31.715 -> Pressure = 967.33 mbar
  18:42:31.715 ->
  18:42:31.715 -> Packet queued
  18:42:31.715 -> 95802: EV_JOINING
  18:42:33.700 -> 217275: EV_TXSTART
  18:42:38.871 -> 540886: EV_JOINED
  18:42:38.871 ->
  18:42:39.366 -> NetID: 19
  18:42:39.366 -> DevAddr: 260Bxxxx
  18:42:39.366 -> AppSKey: 59-65-0B-86-E8-42-5E-D0-xx-xx-xx-xx-xx-xx-xx-xx
  18:42:39.366 -> NwkSKey: 38-E4-86-1D-35-68-80-20-xx-xx-xx-xx-xx-xx-xx-xx
  18:42:39.409 ->
  18:42:39.409 -> 574648: EV_TXSTART
  18:42:45.562 -> 959303: EV_TXCOMPLETE (includes waiting for RX windows)
  18:42:45.562 -> Up: 1, Down: 0
  

• The Arduino MCCI LoRaWAN LMIC library requires less than half flash memory than the Arduino Radiolib library. The example sketch uses only 26918 bytes (41%) of program storage space. Maximum is 65024 bytes.
  

• The LMIC-node repository still does't support development boards with external Semtech SX1262 spi lora modules. This may change with the library Version 5.

• The mikroBUS™-layout will be based on these two modules (Wio LoRa-E5 & RFM95W) already made:
  

• Wio SX1262 mikroBUS™ Modul Prototype:
  
  Prototype mikroBUS™ Modul with Seeed Studio Wio-SX1262 Modem / Prototype top view / Prototype bottom view

  
  mikroBUS™ Prototype Modul on polylab Dev. Board mikroBUS™ Socket / Running my TTN LoRaWAN Node sketch