Cerebot MX3cK JC
USB CONN RADIO
■ SCHEMATIC 2. With the CP2102 and protection diodes out of the way, we have a clear shot to the Cerebot MX3cK's
JC connector. The MX3cK's JC connector houses all of the PIC32MX320F128H's UART2 signals.
■ PHOTO 2.
Being a product
of the 1960's
this shot kinda
reminds me of
to the LEM
■ SCHEMATIC 3. The UART signals mate perfectly with the FTDI-based
USB-to-UART Pmod. RTS and CTS signals are also present on interface
JC. However, the LMZ ZigBee module only requires U2TX and U2RX.
UART Pmod. All we need to know
schematically about the interface is laid out
in Schematic 2. Removing the CP2102 and
protection diode array logically leaves us
with J1, C1, and C3, presenting the
MX3cK’s VBUS power rail to the Lemos
module’s + 3. 3 volt regulator. Note that we
cross the RS-232 protocol TX and RX signals
in our hand-wired USB interface module.
The USB-to-Cerebot MX3cK interface is
attached to the Lemos module in Photo 2.
What you don’t see in this shot is the hand-wiring on the opposite side of the adapter.
In that the MX3cK’s interface connectors
are all female, we’ll use one of the Digilent
14-pin extended male headers to make
electrical contact between the adapter’s
interface and the MX3cK JC interface. This
interface is depicted graphically in
The Baby Of The Bunch
The MX3cK is the smallest and least
adorned Cerebot. However, that doesn’t
mean it can’t hold its own. The MX3cK is
based on the PIC32MX320F128H, which
does not contain an on-chip USB host
engine. The idea behind the design of the
MX3cK is to add peripherals as needed with Pmod
modules. The standard SPI, I2C, UART, and timer
■ PHOTO 3. The chipKIT programmer/debugger is designed to work with
the chipKIT Max32, Uno32, uC32, and MX3cK. I've also used it to develop
home-brewed PIC designs.
via an onboard FTDI FT232RQ. So, we’ll wire our ZigBee
module interface on the MX3cK side to match the USB-to-
58 August 2013