There is a transceiver for M-Bus but it seems to me that it is a virtual
product, he has name - TSS721, a manufacter - Texas, some references in
books, but that's it, it is like god, you have to believe. So i want to
try making one with the PIC.
The M-bus works this way, the master unit controls the bus and he supplys
the power to the slaves, everything in two lines, and it works in both
ways. The communication it's done in two ways, Master to Slave and, Slave
to Master. In the first one, the power of the line swings from the idle
state (max voltage (26 to 42 V), corresponding to Mark) to that value -12
V (Space), the current remains almost unchanged. The slave to master it's
done in a similar way, but in this case what changes is the current (mark
state is 0 mA to 1.5 mA, space state is a maximum 20 mA signal level).
After this short explanation can some of you pic gurus tell me if i can do
this with a pic and a few more electronic parts, or am i dreamming ?

Thank you all.