■ FIGURE 4.
(Does anyone know a good
Programming Adapters Anonymous
group I could join?)
NEXT (AND CERTAINLY
■ FIGURE 3. The completed SUSB-5X2.
at position C4 – again, snip it off.
The 5X2 female header also
requires a minor modification. Before
soldering it in place, remove the pins
at the positions marked with (X). This is
surprisingly simple to do — they easily
pull out from the bottom using needle-nose pliers. The actual assembly of
the stripboard is very straightforward.
First, install all the jumpers but
don’t solder the jumper connections
at C1 and C2 yet. Next, insert the 5X2
header (making sure that the missing
pins are in the correct locations) and
solder the header in place. Finally,
insert the mini-stereo jack and bend
the jumper on the bottom of the board
from C2 to C1 so that it’s touching
the jack’s pin at C1. Then, solder the
connections at C1, C2, C5, and A3.
■ FIGURE 5. The SUSB-5X2 with
■ FIGURE 6. The SUSB-5X2 with the
When all the connections have been
soldered, sand or file any sharp edges
and clean the bottom of the board.
Figure 3 is a photo of the completed SUSB-5X2 adapter and Figures
4, 5, and 6 show how it’s used in three
different situations. In Figure 4, the
SUSB-5X2 connects the AXE027 USB
cable to the Tiny-08 project board.
Figure 5 shows how the SUSB-5X2
can be used to convert the UPA-4X4
programming adapter for a USB
connection to the PC. You don’t see
a power supply in Figure 5 because
the breadboard is mounted on a small
plastic project box with a battery-powered five-volt supply inside. (See
the December 2008 installment of
the Primer for construction details.)
Don’t forget to include the 100K
resistor that ties the serin line to
ground. Without it, any program you
have installed in the PICAXE won’t
run when the programming adapter
is removed from the circuit. In Figure
6, the SUSB-5X2 is flipped upside-down, inserted into the 5X2 male
header on the School Board with the
AXE027 cable attached. As you can
see, this simple little adapter enables
all of our previous serial connections
to continue to function in the Brave
New [USB] World! Nevertheless, I
couldn’t stop at just one adapter.
■ FIGURE 7. The schematic
for the SUSB-01.
Our next programming adapter
(the SUSB-01) combines the mini-stereo jack and the standard PICAXE
programming circuit into one
convenient stripboard circuit. Its
schematic is presented in Figure 7.
You will notice that I haven’t included
the BAT85 diode. Since the AXE027
cable converts the voltage levels to
standard five-volt TTL, the diode is
not necessary. The stripboard layout
for the circuit is shown in Figure 8.
The only thing that is unusual
about the circuit is that the stripboard
has a small notch in it. The notch is
not at all necessary — the board will
function perfectly well without it. I just
wanted as much room as possible on
the breadboard for the necessary
connections to the PICAXE processor.
Construction of the board is very
straightforward, with one caveat. The
three resistors must each be the
smaller 1/6 watt version in order to
fit under the stereo jack. Install the
resistors first, but don’t solder the 10K
lead at B4 yet. Also, don’t forget to
bend and extend the other 10K lead
on the bottom of the board from C2
to C3 and solder it at both positions.
(That’s exactly what I forgot to do and
it took me a while to figure out why
the board didn’t work at first!) Next,
reverse-mount the two three-pin male
headers. (Don’t forget that they need
to be the longer version to be suitable
for reverse-mounting). On the bottom
of the board, bend the 10K lead from
B4 to B5, snip it so that it just touches
the header pin at B5, and solder the six
header pins and the 10K lead at B4.
Next, insert the mini-stereo jack and
attach a short jumper on the bottom
of the board from its pin at A3 to the
adjacent trace at A4. Finally, solder
the pins at E3, C1, and A3, and the