31.3.3.6.3 Burst Accumulation

The figure below shows the timing diagram for the ADC when running in Burst Accumulation mode without using the PGA.

Figure 31-5. Timing Diagram - Burst Accumulation

Note:

If the Low Latency (LOWLAT) bit is set to ‘1’ in the Control A (ADCn.CTRLA) register, the analog modules in the ADC will not turn OFF at the end of the conversion, eliminating the initialization time when triggering the following conversion.
The time from the conversion has finished to the outputs are available in the registers is 0.5 CLK_ADC cycles followed by 1 CLK_MAIN cycle. The last conversion and accumulation require an additional CLK_MAIN cycle. With minimum prescaling, this sums up to 1.5 CLK_ADC cycles before the final outputs are available.

The number of samples to accumulate is set by the Sample Number (SAMPNUM) bit field in the Control F (ADCn.CTRLF) register.

The total conversion time (t_conv) for a Burst Accumulation, in μs, is calculated by:

t_{c o n v} = t_{i n i t i a l i z a t i o n} + \frac{(SAMPDUR + 14) \times SAMPNUM + 1.5}{f_{CLK_ADC}}

The Burst Accumulation conversion rate (f_conv) is calculated by:

f_{conv} = \frac{f_{CLK_ADC}}{SAMPDUR + 14}