The meaning of "1T" is MCU maximum operation clock speed, that is Fcpu = Fosc, because the vast majority of SONIX MCU instructions are single clock cycle, so the system executes an instruction for a minimum time of oscillations. Currently, SN8P2XXX series chips most support "1T", however, in some cases, or some chips can not reach "1T", such as when selecting Noise_Filter Enable in Code Option, the top speed for MCU running clock is only Fcpu = Fosc/4, which is "4T", no matter under what conditions, SN8P2614 can only run the fastest "4T".