Overview
We'll assemble the boards that comprise the Aduino M4 Cube one a time and
then test the circuits on each.
Below you can see the both the top-side (left screenshot) and
bottom-side (right screenshot) views of the four boards that
comprise the M4 Cube.
In
the two screenshots the boards are numbered 1 to 4: top left, top right, bottom left and bottom
right. Board 1 is fully
assembled with the Adafruit ItsyBitsy M4 Express microcontroller
module.
Once
assembled together as a 3" x 3" cube, the top-sides become the exterior and
the bottom-sides become the interior to the M4 Cube.
However, before we do that we really should perform a continuity
test with all four unpopulated boards connected together. Below
right is a video showing the four boards connected together.
Viewed from the top-side of any board, there is a female receptacle
on the left and a male plug on the right. Of course you can only see
where the pins poke through from the bottom-side to the top-side (the connectors are on the bottom-side of the boards).
Getting Power
On
the bottom-side of any board we see Pin 1 of the female connector is
on the bottom left (the SV2 connector in Bd. 1 Schematic A is
intentionally upside down to match the M4 uC). Pins 4 and 3 provide
power.
4 Boards Top-side View
4 Boards Bottom-side View
We'll Test the Microcontroller First with a
Couple of LEDs
From Schematic A of
Board 1, we can see connector SV2's pins 4 and 3 provide 3V3 and
GND, respectively. We can connect a pair of jumper wires from the
female connector
to a breadboard to perform a simple test of the uC. If you don't
have an RGB LED handy (maybe you have yet to order it from Adafruit/Digikey),
use 3 LEDs and 3 current-limiting resistors. In the left adjacent video,
you can see 3 LEDs as well as an RGB LED below them. The
x_3_LEDs_Blink.ino sketch
cycles through the 3 LEDs. We'll test the RGB when we finish Board 1
and move onto Board 2.
I2C, Pull-up Resistors, Real Time Clock (RTC)
We fully assembled Board 1 which included the
RTC. The real time clock is based on the
Adafruit DS1307 RTC breakout board. The IC2 8-pin IC socket is for two pull-up resistors for your
I2C circuits which includes the RTC. Try a 2.2k ohm resistor between
pins 1 & 4 and another between pins 8 & 5, then start up your Arduino IDE, click "File | Examples | RTClib" and run the
"ds1307
sketch". If you cannot find the library containing the examples, consider downloading it
from
here and dropping it in "C:\Users\YourName\OneDrive\Documents\Arduino\libraries".
Do note that it's best to unzip the file to reveal the "RTClib-master"
folder which historically must be renamed to "RTClib" to remove the "-master"
component of the folder name.
It would probably be a good idea to right-click
on the Arduino "libraries" folder and choose "Send to | Desktop
(create shortcut)" because you'll be dropping other libraries there,
too.
Under "Tools", ensure "Serial Monitor" is running;
you should see the current date and time. This tests the I2C circuit
for this board but not necessarily the other three boards. We'll get
there eventually.
If the time reported in Serial Monitor does not
match that of your PC, power off your M4 Cube, remove the battery
from the holder, download the RTC program again to the M4 Cube and
check the time. If all is well reinstall the battery while the M4
Express module is running. Repower the unit to ensure the battery
can hold the correct time.
Ok, let's move onto Board 2 now that Board 1
checks out. If you have issues, don't hesitate to email me at
prefontDon@gmail.com or
donp@networkHorizons.com.. |