February 25, 2017-Finally got a hold of some of the Rigado BMD-350 nRF52 BLE modules; Digikey finally had some in stock so I bought 100 for prototyping, etc. Soldering them onto the board was a piece of cake. They are very small, and the pcb that supports the module is quite thin, I think 0.5-mm.

I had written a program last year when I got a couple of samples from Rigado to test the functionality of the UART bridge. The Arduino sketch (run on the STM32L432 on the Sensor Tile) instantiates two serial ports, one between the STM32L432 and the BMD-350 and one between the STM32L432 and the laptop through the USB cable.

The program starts by putting the module into AT command mode. There I check the module, bootloader, and firmware version numbers set the baud rate, query and/or set various parameters like flow control, parity and whatever else I need to configure the UART bridge parameters. Then the program puts the module back into UART bridge mode and the program waits for valid data to be sent from the laptop console, which is then sent on to a UART console running from Rigado's toolbox on my iPhone as a UART console app. Whatever I type in the UART console on the iPhone app shows up after some delay on the laptop and vice versa.

The speed of the transmission is surprisingly slow. The top speed I expect per Rigado's data sheet is 1 kByte/s, appallingly slow compared to wifi, for example. But the words that appear on either console take a second or two to spell themselves out so the rate seems even slower than this.

Next to do is to package the sensor data and have it sent by the program to the console. I think I am going to have to figure out how to write iOS apps if I want to have a custom interface to accept my Sensor Tile data. Well, at least all of the hardware is working as it should!