There is nothing special with this little board. The schematic is standard (from MAX323/MAX232N datasheet).
Although there are hundreds of projects that treat this topic, I felt the need to redesign in gEDA.
The main reasons are as follows:
- I tried to make schematic easier to follow when make this project on perfboard/stripboard.
- I put also RTS and CTS signals (little used in most microcontroller projects).
- PCB design include mounting holes, can be easily added to a final project (without having to make improvisations in mechanical system).
- Modular design – RS232 support is used when it is needed (In fact, I started this project because I needed only temporary a serial link)
- gEDA schematic and PCB can be easy included in another (bigger) custom project
Ordinary components. For MAX232N 1uF polarised capacitors can be replaced with 0.1uF unpolarised capacitors.
I bent pins to match the board step. I chose to bend 4 pins, not 5.
I drill two holes ~ 3mm, at ~ 25mm distance.
DB9 female connector fits perfectly. In accordance with Wikipedia this connector is correctly called DE-09, but as long as almost everyone uses DB9, I will keep this name.
Almost all components in place.
… and soldered.
Below is a preview of the board as it was generated by gEDA.
The design was made rugged; often RS232 cables are heavy and stiff and we want better mounting of this board (in a final project).
Download gEDA Project from here:RS232TTL gEDA Project.zip