Figure 3-7. System and User Push Buttons
1
4
2
3
TACT SPST
SW1
WKUP
1
4
2
3
TACT SPST
SW2
1
4
2
3
TACT SPST
SW3
nSTART_SOM
USER_BUTTON_PB02
GND
1
4
2
3
TACT SPST
SW4
100R
0402
5%
R70
100R
0402
5%
R71
100R
0402
5%
R72
100R
0402
5%
R73
10k
0402
R74
NRST
100k
0402
R156
VDDBU
VDDBU
3.4.4
Disable Boot
One jumper (J8) controls the selection (CS#) of the bootable memory components (QSPI) using a noninverting 3-
state buffer.
Figure 3-8. QSPI CS Disable Boot
OE
1
A
2
Y
4
GND
3
VCC
5
NL17SZ125-D
U2
JP2
1
2
J8
10k
0402
1%
R77
VDD_3V3
0.1uF
10V
0402
C3
10k
0402
R82
DNP
QSPI_CS_PB6
NCS_QSPI
Jumper on = Disable
The rule of operation is:
• SW2 (RESET) pressed and J8 open = booting from QSPI on WLSOM1
• SW2 (RESET) pressed and J8 closed = booting from external QSPI. The QSPI on WLSOM1 is disabled.
Refer to the SAMA5D2 Series data sheet for more information on standard boot strategies and sequencing.
3.4.5
Secure Digital Multimedia Card (SDMMC) Interface
The SD (Secure Digital) Card is a non-volatile memory card format used as a mass storage memory in mobile
devices.
3.4.5.1
Secure Digital Multimedia Card (SDMMC) Controller
The ATSAMA5D27-WLSOM1-EK1 features two Secure Digital Multimedia Card (SDMMC) interfaces that support the
MultiMedia Card (e.MMC) Specification V4.41, the SD Memory Card Specification V3.0, and the SDIO V3.0
specification. It is compliant with the SD Host Controller Standard V3.0 Specification.
ATSAMA5D27-WLSOM1-EK1
Baseboard Components
©
2019 Microchip Technology Inc.
User Guide
DS50002931A-page 12
