embedded - Read Write option of registers -

i found -> r/c notation in 1 atmel chip specification, in section registers:

i assume stands read clear register, in interrupt status registers. bothers me. notation of registers rc. <- note without forth-slash between letters. same document notation of r/w means register can read or written, not @ same time, or same command/instruction. forth-slash symbol must represent mutually exclusive operation, not 1 inevitably follows other.

so r/c means:

• when read register automatically cleared?
• the register can read or cleared? - how cleared?

assuming you're talking this datasheet, posted information register list. if had looked in comment column of list, says "refer table-11". going table 11, says "resolution 0.01cf. cleared after read." table 12 says cleared after read.