SPRUJ28E November 2021 – September 2024 AM68 , AM68A , TDA4AL-Q1 , TDA4VE-Q1 , TDA4VL-Q1
In open-drain mode, due to protocol requirement, low period cannot be shorter than 160ns to support slowly rising SDA line. To fulfill this constrain in I3C SDR mode, the low period must be always extended beyond the value resulting from the base I3C frequency. The low period of SCL is extended by the value programmed in I3C_PRESCL_CTRL1[7-0] OD_LOW bit-field, which can be calculated using the following equation:
The I3C_PRESCL_CTRL1[7-0] OD_LOW bit-field resolution is set to ¼ of SCL period. The high period remains unchanged and is equal to half-period of I3C frequency.
The actual SCL low period used in open drain mode results from the following equation: