90 Silicon chip Australia’s electronics magazine siliconchip.com.au
display to any extent with the Micro-
mite, as the BASIC interface is quite
slow.
But the BASIC code is certainly a
good starting point, and may be suffi-
cient for some applications.
Before we get to the assembly of the
breakout board for this display, let’s
take a look at a couple of other candi-
dates that we evaluated.
Contestant number two:
Altronics Z-0575
The next board is a 3.2 inch LCD
screen with no touch panel. It’s de-
signed to plug into an Arduino Mega,
and it is available from Altronics,
Cat Z6527 (www.altronics.com.au/p/
z6527) as well as other sources. Altron-
ics say that it has an ILI9481 controller
IC, and they appear to be correct, as it
works with Arduino libraries designed
for that controller chip.
This display has a 16-bit parallel in-
terface and is designed to work with
contiguous port pins on the Arduino
Mega, meaning that, in theory, it will
is capable of very fast communication
using direct port writes.
But that also makes it virtually im-
possible to use with a regular Arduino
or a Micromite.
Its header layout is interesting.
There is a long 2x18 pin header at one
end, which suits the large header block
at one end of the Mega.
There is also a small 2-pin header
which connects to the 3.3V and RE-
SET pins at the other end of the Mega.
This requires the display to rest on the
USB socket for support while blocking
practically all of the other pins.
Interestingly, the full-size SD card
socket is deep inside the board outline
and is not accessible while the board
is attached to a Mega.
On the same side as the SD card
socket are three small SSOP ICs (which
are responsible for converting between
the Arduino’s 5V logic levels and the
display’s 3.3V) as well as a capacitor,
resistor, voltage regulator and an un-
populated SOIC-8 footprint.
The specification sheet notes that
the display will work from 3.3V to
5.5V, so it might also be suitable for
3.3V boards such as the Arduino Due,
although we have not tried this.
On the front of the display is a tac-
tile pushbutton, which is connected
between the GND and RESET pins
on the Mega board, so that pressing
it resets the microcontroller on the
Mega board.Getting it working
Altronics provide a good amount
of sample code, which can be down-
loaded from the downloads tab of the
product page linked above.
This download includes manuals,
libraries and images of sample dis-
play output.
We used an Arduino Mega to test
it, mainly because most of the other
micro boards we had on hand didn’t
have enough I/O pins to drive it – you
need 20 I/O pins just to run the dis-
play, and even if you have that many
free, it would be fiddly to wire it up
using jumper leads (see Fig.2).
The board is effectively a shield for
the Mega and directly plugs in on top.
While easy to insert, the large header
is hard to remove, and we found we
had to take care detaching the shieldby wiggling the display to gently ease
the pins out so that they don’t catch
and bend.
We extracted the “Arduino Demo_
Mega2560” folder from the zip file and
copied the contents of the “Arduino
Demo_Mega2560\Install libraries”
folder to the Arduino libraries folder.
In Windows 10, our libraries folder is
at “Documents\Arduino\libraries”.
We then had a libraries folder as
shown in Fig.3.
It appears these libraries are adapt-
ed from those that can be downloaded
from http://www.rinkydinkelectronics.com/
library.php This is a handy website
which also offers fonts that can be
used with graphical LCDs.
We restarted the Arduino IDE for
it to recognise the newly copied li-
braries.
The example sketches can be found
in the “Arduino Demo_Mega2560”
folder. The “Example01-UTFT_
Demo_480x320” sketch cycles through
a few demonstration patterns.
The other sample sketches demon-
strate fonts, buttons and bitmaps, al-
though, as we noted earlier, this dis-
play does not feature a touch panel, so
it was not possible to test the button
sketches properly.SD card slot
As we mentioned, there is an SD
card slot tucked under the board.
This can be a handy as it allowsFig.2: a pin map for the Altronics
display shield, designed to plug into
an Arduino Mega. We have added the
Mega pin numbers for clarity, although
these are not needed for the direct port
writes used in the library code.Contestant number two: this display
board lacks a touch panel but sits neatly over the top of an
Arduino Mega. The tactile switch resets the connected microcontroller when pressed.