Silicon Chip – April 2019

siliconchip.com.au Australia’s electronics magazine April 2019 91

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Connecting Micromite

Plus to Windows 7

Recently, the Windows 7 installa-
tion on my PC became seriously cor-
rupted. I had to go through the repair
process which unfortunately inter-
feres with the installed drivers. Al-
though most USB devices worked
normally after this, when I plugged a
Micromite Plus device (August 2016;
siliconchip.com.au/Article/10040)
into my computer, it could not find a
suitable driver.
I spent some time looking around for
a separately installable driver to solve
the problem, even though I thought
that the PIC32 would automatically
install one when connected to the USB
port, but I couldn’t find a suitable driv-
er. I also tried plugging the Micromite
Plus into two other Windows 7 com-
puters with the same result.
Finally, I tried the Micromite Plus on
a Windows 10 box. It worked straight
away. Does this mean that the Micro-
mite Plus is no longer supported by
Windows 7? (J. W., Marsfield, NSW)

• We found the following text on page
  42 of the Micromite Plus manual, re-
  garding the USB console:
  The protocol used is the CDC (Com-
  munication Device Class) protocol and
  there is native support for this in Win-
  dows 10, Linux (the cdc-acm driver)
  and macOS. Mac users can refer to the
  document “Using Serial Over USB on

the Macintosh” on http://geoffg.net/

maximite.html

If you are using Windows you will

need to install the Windows Serial Port

Driver (available from http://geoffg.net/

maximite.html#Downloads). Full in-

structions are included in the download

and when you have finished you should

see the connection in Device Manager

as a numbered communications port.

So this explains why the device

worked when plugged into a Windows

10 computer – you don’t need to install

a driver manually, but you do for Win-

dows 7. Your Windows Repair must

have removed the driver you already

had but re-installing it should fix that.

Unfortunately, the download link

given no longer seems to work but you

can download this same Windows Se-

rial Port Driver from Geoff Graham’s

website at: http://geoffg.net/maximite.

html#Downloads

Building the GPS

Analog Clock

I am enthusiastic about modify-

ing analog wall clocks and a friend of

mine recommend that I build the GPS-

Synchronised Analog Clock adaptor,

based on your March 2009 design, us-

ing the Altronics K1129 kit. I would

appreciate if you help me how to get

a hold of the complete kit or PCB for

that project. (A. R., via email)

• Unfortunately, Altronics have dis-

continued the kit for that project. We

published a revised version of that

project in our February 2017 issue

(siliconchip.com.au/Article/10527)

and you can purchase the PCB, pro-

grammed microcontroller and some

other components for that version from

our Online Shop at: siliconchip.com.

au/Shop/8/4160

Incorrect measurement

on Super-7 AM Radio

I have built the Super-7 AM Ra-

dio which you published in your

November & December 2017 issues

(siliconchip.com.au/Series/321) and

I am having a problem with the align-

ment procedure.

On page 70 of the December 2017

issue, there is a table showing the ex-

pected voltages at various test points

on the PCB. I have measured the volt-

ages on my unit and get very close

agreement, except for TP8. The reading

I get is about 1-2V but the value is not

stable. The article says that TP8 should

be about 4.3V. I cannot work out why

the reading I get is so different.

Could I have a faulty transistor or

diode D2? I also measured the cur-

rent drain as described on page 70 and

obtained a reading of 4.3mA which I

thought is OK. I hope you can help

with my problem. (P. V., Tarneit, Vic)

• You could have a bad solder joint on
  one of the pins of Q5, Q6, D2 or VR2.

I am constructing the GPS-Synced

Frequency Reference as per Silicon

chip, October & November 2018

(siliconchip.com.au/Series/326).

I have already built the Micro-

mite LCD BackPack V2 (May 2017;

siliconchip.com.au/Article/10652)

with Mosfets Q1 and Q2 installed.

On page 79 of the November

2018 issue, there is a reference to

the fact that pin 26 of the Micro-

mite BackPack cannot be used for

software controlled backlight. It

says to omit Q1 and Q2 and fit the

100 W potentiometer for backlight

control instead.

Since my BackPack already has

Q1 and Q2 fitted, does this mean that

I have to remove these two compo-

nents? (C. L., Chapel Hill, Qld)

• You only need to remove Q1 and
  its associated 10kW pull-up resistor.
  Alternatively, you could cut the
  track to the gate of Q1 (the pin near-

Modifying BackPack V2 for GPS Frequency Reference

est the bottom edge of the PCB) and

leave it in place.

Q2 then won’t do anything as Q1

will not be driving its gate; it will

remain switched off due to the 1kW

gate pull-up resistor.

You will still need to fit potentio-

meter VR1 to control the backlight,

or you could merely fit a wire link in

its place, if you want the backlight to

remain on at full brightness when-

ever the device is powered.