56 November 2016
embedded in an easy-to-use module. I have chosen the Raytac module
because the Raytac folks were “Johnny on the spot” with their nRF52832
module, which is referenced in the Raytac documentation as the MDBT42Q.
I have designed and assembled an
MDBT42Q development platform that
we will use to bring our BLE application
to life. The MDBT42Q design is depicted
graphically in Schematic 1.
The MDBT42Q development board
in its silicon and fiberglass form is under
the camera in Photo 3. The 32.768 kHz
crystal is a must for low power operation.
The SoftDevice in particular utilizes the
32.768 kHz crystal. The ARM core of the
MDBT42Q runs on the 64 MHz clock.
You can see the 32 MHz crystal that drives
the MDBT42Q’s 2x PLL in the uncovered
module captured in Photo 4.
Take another look at Photo 1 and you
will see that the J-Link Pro is sporting an
OLIMEX JTAG 20-10 adapter. This adapter
allows us to mount a 1.27 mm pitch
10-position debug/programming header on
our MDBT42Q development platform.
n PHOTO 3. The design is realized on a standard double-sided printed
circuit board (PCB).
n SCHEMATIC 1. This schematic is simple because all of the magic resides inside of the MDBT42Q module. All of the
free GPIO pins are terminated at a header point on the PCB.
n PHOTO 4. The MDBT42Q is a standard
nRF52832 circuit that has been FCC
certified and placed within an easy-to-mount package.