The "Board"
We will implement a flexible design for a multipurpose 32-bit microcontroller-based platform. This model
will be based on a six UART-equipped
PIC32MX795F512L. One of the sextet of UARTs shall
drive an FTDI FT232RL USB-to-serial IC. Another one of
the PIC32MX795F512L’s UARTs will be used to service a
“true” RS-232 port, which will be overseen by an
STMicroelectronics ST3232C RS-232 interface IC.
A third PIC32MX795F512L UART will be pinned out
for general-purpose use. The fourth UART will act as a
pipeline to a microSD card under the control of an Atmel
ATMega328P.
In a previous Design Cycle (June 2015), we designed
a microSD implementation that was capable of being
driven by a PIC32MX795F512L. We’ll “reuse” and include
the details of that design in this month’s project. The
inclusion of the PIC32MX795F512L-driven microSD card
allows us to utilize the microSD card portal for
bootloading, web serving, and general-purpose data
handling. The native microSD card interface will be
supplemented by a 1 Mbit
25LC1024 EEPROM.
In that other
Microchip SPI Flash
memory ICs are pin-compatible, the EEPROM
space can be occupied by
a denser Flash memory
device if necessary. Just in
case we need to interface
an SPI-based IC or
peripheral to our
PIC32MX795F512L, we’ll
also pinout a standard SPI
portal.
What would any
microcontroller-based
design worth its salt be
worth without LEDs? To
offload our
PIC32MX795F512L’s I/O
subsystem, we’ll drive all
THE DESIGN CYCLE
Giving Our “Board” Wings to
Fly Over LANs or the Internet
■ BY FRED EADY
60 August 2015
Soldering is a perishable skill. So, every time I get a chance, I pick up a soldering iron and
make some solder joints. I also love to lay out printed circuit boards (PCBs). That's because
after I lay one out, I have to solder stuff to it. More times than not, there's a microcontroller
on that PCB. That leads to having to hone my programming skills. So, I guess that means
that I really love to design and build electronic gadgets. I'm especially fond of Ethernet-equipped gadgets because that most always forces a connection to another Ethernet-laden
gadget over an LAN or the Internet. So, guess what we're about to do ...
■ Photo 1. This little board allows you to send it, receive it, process it, and store it. You can
do this via wired Ethernet or external wireless modules. What you don't see in the shot is
the Ethernet magnetics package which is mounted on the opposite side of the PCB.
