We've looked at a fair number of USB-to-serial adapter
boards, and even made one ourselves (but then the chipset went
obsolete-sorry!). We've now found these units by SparkFun to
be quite nice. The brains of this board is the FTDI
FT232RL in 3.3V configuration,
a really solidly proven adapter
chip, and SparkFun has packaged it into a nice and tidy bread-board
friendly unit.
What makes this particular unit especially stand out is that it matches
the function of the native FTDI USB Cable that is popular with Arduino
users. Instead of having to get a whole bulky cable, add this
adapter to a own USB-to-Mini-B cable for a less expensive and more
flexible alternative! It also has blinky LEDs, which the FTDI cable
doesn't have!
An important advantage with this board is that it
brings out the DTR pin as opposed to the RTS pin of the FTDI cable. The
DTR pin allows an Arduino target to auto-reset when a new Sketch is
downloaded. This is a really nice feature to have and allows a sketch
to be downloaded without having to hit the reset button. This board
will auto reset any Arduino board that has the reset pin brought out to
a 6-pin connector.
The adapter pins match the FTDI cable in that
the pins labeled BLK and GRN match to the colored
wires on the
FTDI cable. The cable black wire GND, green is CTS. Use
these BLK and GRN pins to align the FTDI basic board with your Arduino
(or other microcontroller) board.
So to recap:
- This is the 3.3V FTDI version, which we've found to
program 5V Arduino Pro units just fine!
- An original FTDI cable has the RTS line on pin 6. The
Sparkfun module uses the DTR line on pin 6. Note this if it is
important to your application!
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