driver (the CDC is standard). All PC software using a COM port work without modifications with this virtual COM
port. Under Microsoft
®
Windows
®
, the device shows up as a COM port; under Linux
®
, as a /dev/ACMx device. This
enables the user to use host software which was not designed to be used with USB, such as a terminal program.
3.5.5
Push Button Switches
The SAMA7G54-EK features three push buttons:
• One user push button (SW1) connected to PIO_PA12 for free use.
• One board reset push button (SW2). When pressed, the processor is reset.
• One start or wake-up push button (SW3) connected to the nSTRT pin of the PMIC, used to instruct the PMIC to
initiate a power-on sequence or to make the processor exit Low-Power mode
Figure 3-57. Push Buttons Schematic
1
4
2
3
TL3301NF260QG
SW1
1
4
2
3
TL3301NF260QG
SW2
nRST
0.1uF
10V
0402
C238
VDD_3V3
GND
GND
GND
0.1uF
10V
0402
C239
GND
100R
0402
5%
R219
10k
0402
1%
R218
1
4
2
3
TL3301NF260QG
SW3
nSTART
GND
100R
0402
5%
R227
User, Reset, Start Buttons
USER_BUTTON_PA12
2.2uF
16V
0603
C240
GND
Note:
1.
For more details about the SW3 push button behavior, see
.
3.5.6
Disable Boot
On-board push button SW4 and/or jumper J22 control the selection (CS#) of the bootable memory components,
QSPI and e.MMC NAND Flash, using a non-inverting 3-state buffer for the first memory and a MOSFET for the
second one.
The rule of operation is:
• SW4 (DISABLE_BOOT) or J22 shorted: booting from QSPI and e.MMC NAND FLASH is disabled.
• LED D8 indicates the state of the DIS_BOOT signal:
– Red: the on-board boot memories are disabled.
– Green: the on-board boot memories are enabled.
SAMA7G54-EK
Function Blocks
©
2022 Microchip Technology Inc.
and its subsidiaries
User Guide
DS50003273A-page 64