45.6.2.9 Accumulation

The results of multiple, consecutive conversions can be accumulated. The number of samples to be accumulated is specified by the Sample Number field in the Average Control register (AVGCTRL.SAMPLENUM). When accumulating more than 16 samples, the result will be too large to fit the 16-bit RESULT register size. To avoid overflow, the result is right shifted automatically to fit within the available register size. The number of automatic right shifts is specified in the table below.

Note: To perform the accumulation of two or more samples, the Conversion Result Resolution field in the Control B register (CTRLB.RESSEL) must be set.

Table 45-1. Accumulation
Number of Accumulated Samples	AVGCTRL. SAMPLENUM	Number of Automatic Right Shifts	Final Result Precision	Automatic Division Factor
1	0x0	0	12 bits	0
2	0x1	0	13 bits	0
4	0x2	0	14 bits	0
8	0x3	0	15 bits	0
16	0x4	0	16 bits	0
32	0x5	1	16 bits	2
64	0x6	2	16 bits	4
128	0x7	3	16 bits	8
256	0x8	4	16 bits	16
512	0x9	5	16 bits	32
1024	0xA	6	16 bits	64
Reserved	0xB –0xF		12 bits	0

Table 45-2. Accumulation
Number of Accumulated Samples	AVGCTRL. SAMPLENUM	Intermediate Result Precision	Number of Automatic Right Shifts	Final Result Precision	Automatic Division Factor
1	0x0	12 bits	0	12 bits	0
2	0x1	13 bits	0	13 bits	0
4	0x2	14 bits	0	14 bits	0
8	0x3	15 bits	0	15 bits	0
16	0x4	16 bits	0	16 bits	0
32	0x5	17 bits	1	16 bits	2
64	0x6	18 bits	2	16 bits	4
128	0x7	19 bits	3	16 bits	8
256	0x8	20 bits	4	16 bits	16
512	0x9	21 bits	5	16 bits	32
1024	0xA	22 bits	6	16 bits	64
Reserved	0xB –0xF	12 bits		12 bits	0