Atmel ARM-Based Evaluation Kit AT91SAM9N12-EK AT91SAM9N12-EK Data Sheet

909

SAM9N12/SAM9CN11/SAM9CN12 [DATASHEET]

11063K–ATARM–05-Nov-13

ADC_TRGR

0xF804C0C0

Read-write

Effective only if TRGMOD defines a Periodic Trigger.

Defines the periodic trigger period, with the following equation:

Trigger Period = (TRGPER+1) /ADCCLK

The minimum time between 2 consecutive trigger events must be strictly greater than the duration time of the longest conversion 
sequence according to configuration of registers ADC_MR, ADC_CHSR, ADC_SEQR1, ADC_SEQR2, ADC_TSMR.

When TRGMOD is set to pen detect trigger (i.e. 100) and averaging is used (i.e. bitfield TSAV differs from 0 in ADC_TSMR regis-
ter) only 1 measure is performed. Thus, XRDY, YRDY, PRDY, DRDY will not rise on pen contact trigger. To achieve 
measurement, several triggers must be provided either by software or by setting the TRGMOD on continuous trigger (i.e. 110) 
until flags rise.

31

30

29

28

27

26

25

24

TRGPER

23

22

21

20

19

18

17

16

TRGPER

15

14

13

12

11

10

9

8

–

–

–

–

–

–

–

–

7

6

5

4

3

2

1

0

–

–

–

–

–

TRGMOD

0

NO_TRIGGER

No trigger, only software trigger can start conversions

1

EXT_TRIG_RISE

External Trigger Rising Edge

2

EXT_TRIG_FALL

External Trigger Falling Edge

3

EXT_TRIG_ANY

External Trigger Any Edge

4

PEN_TRIG

Pen Detect Trigger (shall be selected only if PENDET is set and TSAMOD = Touchscreen 
only mode)

5

PERIOD_TRIG

Periodic Trigger (TRGPER shall be initiated appropriately)

6

CONTINUOUS

Continuous Mode

7

–

Reserved