- remember it is a polarised component;
the short lead (k) needs to be connected
to 0V. Also check the resistor value. If you
have a value much higher than 1kΩ then
the LED may be too dim to see if you’re
working in bright sunlight. These quick
checks will resolve any issue and your
test circuit is now ready to be used for
testing the I/O points on the DM.
Errata
In Part 3 (Fig.2 on page 63) the component
side of the stripboard layout incorrectly
shows a track cut at position X21. This
cut should not be there. The track side of
the stripboard in Fig.2 is correctly shown
with no cut at X21. If you have made this
cut, then simply solder a small wire link
to bridge the cut. It is mentioned here
because a cut at X21 would isolate I/O pin
15 from the 20-way header; and hence the
following test would fail for I/O 15 on J12.
There are now three possible scenarios
for your MKC test software – it is:
- Installed and running
- Installed but is not running
- Not installed.
You may know the scenario you are in,
but for now just follow the guide below.
Referring to Fig.2, insert the test probe
into the position highlighted with number
2 on the 14-way header J10. If you see the
test LED briefly flash at approximately
one-second intervals, then you have the
MKC test software running on your MKC
(scenario 1).
If the test LED is not flashing, then
type RUN on the TeraTerm keyboard and
check to see if the word RUN appears
on the TeraTerm screen. If so, press the
Enter key and check to see if the test LED
flashes. If the test LED begins to flash,
then scenario 2 applies to you; otherwise
it is scenario 3.
For scenarios 1 and 2, simply go ahead
and work through the 19 numbered
points on J10, J3 and J2. At each point
you should see the test LED flash. If any
point does not flash, then there is an
issue with that I/O signal between the
PIC inside the MKC and the point under
test. Check for open circuits and for track
shorts using the methods discussed in
Part 2, page 69 (Useful test info section).
For those of you that have installed the
20-way header (J12), go ahead and test
the 19 I/O points on that too (note that
the left-hand point (reset) will not flash
the test LED). If everything checks out
then jump over the next section and go
to: Configuring your MKC and TeraTerm.
If you are here then you must fall
under scenario 3 (ie, MKC test software
not installed). Hopefully, if you type
anything into TeraTerm you will see the
characters appear on the TeraTerm screen.
If not, then Press (and hold down) the Ctrl
key and then press the C key. This will
stop any program that may be running.
Now press any key and you should see
the character(s) appear on the TeraTermFig.3. Ensure your
TeraTerm setup screens
match these settings
and remember to save!screen. If not, then you will need to
check your TeraTerm communication,
as discussed in Part 3.
Once you have the command prompt
on the TeraTerm screen (the ‘>’ character)
and are able to type and see the characters,
then you can begin to methodically test
the 19 I/O signals on the DM as follows.