I just finished building a first version of the level convertor on a breadboard. You can see the schematics and a few pictures above (click the thumbnails to enlarge).
- 2 x 100nF non polarized capacitors
- 3 x 470nF non polarized capacitors
- 1x DE-9 Female connector
- 1x 4-pins PCB connector
- 1 x MAX3232CPE+
- 1 x bread board
To connect to the PC, you can use a standard crossed serial cable. For La Fonera, the standard settings are:
- baudrate: 9600bps
- data bits: 8
- stop bits: 1
- parity: none
- flow control: none
This level convertor can be used for speeds up to 115200bps, and works with TTL inputs from 2,7V up to 5,5V.
Next up I’ll make the same schematic in a more permanent and less cluttered form.