Notes on the Sparkfun FTDI USB to serial adapter
I purchased an FTDI Basic module from Sparkfun.
I have hopes of attaching this to a piece of legacy equipment
so as be able to connect it to a USB port.
The FTDI module is simply a FT232RL chip and a few components
(including Tx and Tx LEDs !!) on a tiny board.
Here is the schematic
This device provides 6 pins with TTL level signals:
- pin 1 DTR (output from the FT232 pin 2)
- pin 2 RxD (input to the FT232 pin 5)
- pin 3 TxD (output from FT232 pin 1)
- pin 4 Power
- pin 5 CTS (input to the FT232 pin 11)
- pin 6 Ground
Note that pin 4 (Power) is either 5V from the USB (the default),
or 3.3 volts from a regulator built into the FT232RL chip (up to 50 mA).
Either way, this supplies power to the attached AVR controller, or is
intended to. In other applications it should probably be a no-connect.
Older versions of the board brought out RTS instead of DTR,
but DTR is better because it allows an AVR target to autoreset
when new firmware is downloaded, avoiding the need to press reset.
(The trick is that the reset needs to be connected to DTR).
Feedback? Questions?
Drop me a line!
Tom's Computer Info / tom@mmto.org