"Citta in this context is not used in the usual sense of mind but in the sense of aspiring mind, mind aspiring for communion with the Supreme I-consciousness of Shiva."
Emphasis added, since the "I" can be easy to miss.
Discuss your thoughts and impressions.
My understanding of "chittam mantra" is mind becomes mantra. Mantra in itself translates to "Mann" (meaning the mind) + "Tra" (To liberate). Hence, freedom of/from the mind. This could be synonymous to the communion with the I-consciousness of Shiva or freedom from the world of causality.
Wasn't aware of the root meaning of the word, thank you for that tidbit!