SPRUJD3A July 2025 – October 2025 F28E120SB , F28E120SC
External signal sources vary in the ability to drive an analog signal quickly and effectively. To achieve rated resolution, the signal source needs to charge the sampling capacitor in the ADC core to within 0.5 LSBs of the signal voltage. The acquisition window is the amount of time the sampling capacitor is allowed to charge and is configurable per SOCx by the ADCSOCxCTL.ACQPS register.
ACQPS is a 8-bit register field that can be set to a value between 0 and 255.The 2 upper bits (ADCSOCxCTL.ACQPS[7:6]) configure the base duration and cycle prescalers. The base duration can be set to values of 0, 64, 192, or 448 with corresponding cycle prescalers of 1, 2, 4, and 16 respectively. The lower 6 bits (ADCSOCxCTL.ACQPS[5:0]) in the register field configure the additional cycles to be multiplied by the prescaler and added to the base duration.
Acquisition Window [SYSCLK cycles] = (Base duration) + ((Additional cycles + 1)*(Prescaler))