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PIC
and AVR
Breakout Boards
By Tim Blythman
T
he three Breakout Boards
we designed are intended to plug
into a breadboard while also connecting to a Snap or PICkit 4 programmer for power and programming.
Two can be used with the four PIC
parts we discussed in the feature article: one for SOIC parts and the other for
DIP. The circuit for these two boards is
identical – see Fig.3.
The other is designed for the
AVR64DD32 and its circuit is shown
in Fig.6. The PICkit 4 cannot provide
power in UPDI mode (as for newer
AVR chips), so we recommend using
a Snap modified to provide 5V with
the AVR64DD32.
PIC Breakout
These PIC Breakout Boards accept
SOIC (Fig.4) or DIP (Fig.5) devices
up to 20 pins. They are designed
to provide basic programmer connections as well as the two passive
components needed for a minimal
working setup.
They break out each pin of the
microcontroller to an adjacent header
pin. This could be a standard header
below to plug into a breadboard, or
a header socket above, into which
you can plug jumper wires. We’ll
describe the parts needed to plug into
a breadboard.
Many recent 8-bit PIC parts have
standard pinouts on their topmost pins,
shown as pins 1-4 and 17-20 in Fig.1.
So this Breakout should work for most
recent 8-pin, 14-pin and 20-pin 8-bit
PICs, as long as they are placed at the
top of the Breakout.
You could fit the DIP breakout with
a 20-pin narrow IC socket to allow
parts to be changed in and out. Alternatively, a narrow ZIF (zero insertion
force) socket could be used, turning
the Breakout Board into a handy programming jig.
Assembly of the PIC Breakout
During construction, refer to the appropriate overlay diagram, Fig.4 or Fig.5.
Both are double-sided boards, with the
SOIC version being 15.5 × 32.5mm and
the DIP version being 15 × 35.5mm.
If you have the SMD version, start by
soldering the microcontroller in place.
If it is a 20-pin part, it will be a tight
fit, so keep it clear of the pads for the
header pins.
Apply flux and rest the chip in place,
ensuring that pin 1 goes to the end near
CON1. 8-pin and 14-pin parts won’t be
as fussy as they are narrower but should
have their pin 1 in the same location.
Tack one lead and check that all the
remaining pins are aligned before soldering the others. Check there are no
bridges between pins or to the header
pin pads; if there are, clean them up
with flux, solder braid and a clean
iron. Then use an appropriate solvent
to remove any remaining flux.
Fig.3: the 20-pin Breakout Board circuit connects the
programmer header (CON1) to the chip with all pins
also going to a pair of SIL headers.
20-pin PIC Breakout Board
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Figs.4 and 5: the breakout boards have been designed
for breadboarding or general use (eg, plugging into
a pair of SIL sockets). They accept 8, 14 and 20-pin
devices with pin 1 in the same position.
Practical Electronics | October | 2023
If you have the DIP version, solder
the socket or IC in place. Like the SMD
part, you can tack one lead and then
check that the socket or IC is flat and
flush before soldering the other leads.
Next, solder the capacitor and resistor and trim their leads close to the PCB.
To fit and align the header pins, it’s
a good idea to plug them into a breadboard first. This will guarantee that the
pins will align with the breadboard in
the future. Place the PCB over the pins
and push it down flat. Tack the corner
pins and adjust if necessary before soldering the remaining pins.
Finally, fit the right-angled header,
CON1. Then connect your programmer,
being sure to align the arrows that mark
pin 1 on both the programmer and the
Breakout’s programming header.
AVR Breakout
The PCB overlay for the 16 × 53.5mm
AVR Breakout Board is coded 24110223
and is available from the PE PCB Service – it is shown in Fig.7. We’ve made
it as narrow as possible to conserve
breadboard space, resulting in a gap in
the middle of the rows of pins. It therefore has 16 pins down each side, but
they take up 20 rows on a breadboard.
Since there are two main power rails
and the VDDIO2 pin for the MVIO feature, there are three bypass capacitors.
The jumper shunt connects the two
rails, which is necessary for applications that don’t use MVIO.
The 1kW resistor on this board is
connected between VDD and UPDI.
This is discussed in the accompanying
Parts List – PIC Breakout Board
1 double-sided PCB coded 24110225, 15.5 × 32.5mm (for SOIC parts) OR
1 double-sided PCB coded 24110222 15 × 35.5mm (for DIP parts)
1 8/14/20 pin PIC16F18xxx microcontroller in SOIC/DIP package
1 20-pin DIL IC socket (optional; for DIP micros)
2 10-way pin headers, 2.54mm pitch
1 5-way right-angle pin header, 2.54mm pitch (CON1)
1 100nF MKT or ceramic capacitor
All PCBs available from
1 10kW axial 1/4W resistor
the PE PCB Service
Parts List – AVR64DD32 Breakout board
1 double-sided PCB coded 24110223, 16 × 53.5mm
4 8-pin headers, 2.54mm pitch
1 4-way right-angle male header, 2.54mm pitch (CON1)
1 2-way header and jumper shunt, 2.54mm pitch (JP1)
3 100nF MKT or ceramic capacitors
1 1kW axial 1/4W resistor
1 AVR64DD32-I/PT 8-bit microcontroller, TQFP-32 (7×7mm) (IC1)
article and it is necessary if you are
using a Snap programmer.
Assembling the AVR Breakout
The pitch of the TQFP AVR64DD32
chips is finer than SOIC parts, but
still not too difficult to solder. Apply
flux and rest the part roughly in place,
ensuring pin 1 is in the correct location,
then tack one lead. Take care to check
that all four sides are aligned before
tacking another pin on an opposite
corner, then soldering all the remaining leads.
Remember that you can use flux, solder wicking braid and a clean iron to
remove any bridges.
Fit the three capacitors next and
follow with the 1kW resistor if that
is needed. JP1 can be installed next.
You should leave the jumper shunt in
place unless you plan to connect an
alternative VDDIO2 supply and activate MVIO.
Like the DIP PIC Breakout, you can
align the header pins by pushing them
into a breadboard first. Leave a gap of
four rows in the middle, then push
the PCB down firmly before soldering
the pins.
Finally, fit the four-way header
(CON1) for the programmer and attach
the programmer. The arrow marks pin
1 and the programmer should have a
corresponding mark.
MPLAB X
If you haven’t used the MPLAB X IDE
before, see our PIC n’ Mix feature (PE,
July and September 2020; January,
March, May, July 2021). If you need to
manually install the DFP (device family pack) for the AVR64DD32 or any of
the PIC parts, use the Tools → Packs
menu item.
Reproduced by arrangement with
SILICON CHIP magazine 2023.
www.siliconchip.com.au
Fig.6: The AVR64DD32
Breakout Board is
similar but brings the
pins out to four headers
as the chip has pins on
four sides.
AVR64DD32 Breakout Board
Practical Electronics | October | 2023
Fig.7: the four headers
are arranged in two
rows so they can
be plugged into a
breadboard. The gaps
mean the board is
narrow enough for a
standard breadboard.
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