PIO
Mnemonic
PIO Shared
Signal Description
PA26
QSPI0_IO2
Nand Flash
Data2
PA27
QSPI0_IO3
Nand Flash
Data3
3.2.8.3
CS Disable
On-board push button PB2 controls the selection (CS#) of the bootable memory components (QSPI and
serial Flash) using a non-inverting 3-state buffer.
Figure 3-19. CS Disable
BOOT_DIS
QSPI Flash CS
SPI Flash CS
QSPI0_CS_PA23
SPI0_CS0_PA17
GND_POWER
GND_POWER
VDD_3V3
SPI0_NPCS0_PA17
QSPI0_NPCS_PA23
DISABLE_BOOT
C116
100nF
VCC
GND
U11
NL17SZ126DFT2G
1
2
3
4
5
VCC
GND
U12
NL17SZ126DFT2G
1
2
3
4
5
R184
10K
C117
100nF
R185
10K
R178
10K
The rule of operation is:
•
PB2 (DISABLE_BOOT) and PB3 (RESET) pressed = booting from QSPI or optional serial Flash is
disabled.
Refer to the SAMA5D2 Series datasheet for more information on standard boot strategies and
sequencing.
3.2.8.4
Serial EEPROM with Unique MAC Address
The SAMA5D2-PTC-EK board embeds one Microchip 24AA02E48 I²C serial EEPROM connected on the
TWI1 interface.
The TWI interface is I
2
C-compatible and similarly uses only two lines, namely serial data (SDA) and serial
clock (SCL). According to the standard, the TWI clock rate is limited to 400 kHz in Fast mode and 100
kHz in Normal mode, but configurable baud rate generator permits the output data rate to be adapted to a
wide range of core clock frequencies. The TWI is used in Master mode.
The 24AA02E48 features 2048 bits of Serial Electrically-Erasable Programmable Read-Only Memory
(EEPROM) organized as 256 words of eight bits each and is accessed via an I
2
C-compatible (2-wire)
serial interface. In addition, the 24AA02E48 incorporates an easy and inexpensive method to obtain a
globally unique MAC or EUI address (EUI-48).
The EUI-48 addresses can be assigned as the actual physical address of a system hardware device or
node, or it can be assigned to a software instance. These addresses are factory-programmed by
Microchip and guaranteed unique. They are permanently write-protected in an extended memory block
located outside the standard 2-Kbit memory array.
CAUTION
Caution:
The EEPROM device is used as a “software label” to store board information such as
chip type, manufacturer name and production date, using the last two 16-byte blocks in
memory. The information contained in these blocks should not be modified.
SAMA5D2-PTC-EK
Board Components
©
2017 Microchip Technology Inc.
DS50002709A-page 20
