I'm a student of electronic engineering. I'm working on a project to build a HART "soft modem" using a microcontroller.
Studying the HART specs. (especially the physical link layer) i stumble about following:
... whithin a character, the bit timing is defined by the baud rate. Normally there may be any amount of idle time (at the logical 1 level) between characters, however, HART requires that idle time not exceed 1 byte time. ...
does "logical 1" mean that the carrier of 1200Hz is still there or a "high Level"?
I can't find detailed information about this.
Does anoybody have information about this?