User manual
SAM9N12/CN11-EK User Guide 4-17
11186A–ATARM–29-Nov-12
4.3.20 Push Buttons
SAM9N12/CN11-EK has three mechanical push buttons for system application (PB1 to PB3) and one for
free use (PB4).
4.3.20.1 PB1 Output Enable Chip Select
Access to the RomBoot:
1. Press simultaneously the PBs OE-CS and NRST
2.
Release the PB NRST
3. Then release PB OE-CS
The program boots to the ROM code whatever the contents of the NAND Flash or serial DataFlash.
Please re
fer to SAM9N12/CN11 datasheet boot strategy for details.
Figure 4-24. PB1
4.3.
20.2 PB2 NRST
The NRST pin is bidirectional. It is handled by the on-chip reset controller and can be driven low to pro-
vide a reset signal to the external components, or be assert
ed low externally to reset the microcontroller.
It will reset the core and the peripherals except for the backup region.
Figure 4-25. Push Button
NRST
PB3
PB_USER
NRST
WAKE UP
PB2
1
42
3
PB3
1
42
3
PB4
1
42
3
R150 100K
WKUP
VDDBU