PROFIBUS Project
Some years ago I designed a simple Profibus to RS232 bridge using a Siemens SPC3 ASIC and a fairly generic Atmel 8051 CPU running at 11.0592 MHz. The program converts received network data to an ASCII string and sends it on demand over RS232. Data coming in on RS232 is sent out to the master. The code is written in C and compiled with Keil C51 v7.
See the links at right for photo, schematic, and source code.
This board and code was tested on a PROFIBUS network at speeds from 9600 baud to 12 Mbaud using a SST 5136 card as the PROFIBUS DP master.