Sorry, I don't know the Attiny 61 series so well that I can answer your specific questions without consulting the data sheet myself. Unfortunately, I don't have the time for that at the moment, because I'm in the middle of a project myself, I could only answer the opening question so directly because I only recently pointed out the characteristics of the 61 series to someone that they are planning to use of a BLDC controller. I myself last used Chip 3 years ago. At the moment I am working particularly intensively with the Attiny167 because of the 16KB Flash