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NUC970 Technical Reference Manual
Publication Release Date: Dec. 15, 2015
- 69 -
Revision V1.30
NUC97
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5.2.5 Power-On Setting
After power on reset, Power-On setting registers are latched to configure this chip. The table
shown below describes the definition of each power-on setting bit.
Power-On Setting Pin
Description
Power-On Setting Register
Bit
USB0_ID
USB Port 0 Role Selection
0 = USB Port 0 act as a USB host.
1 = USB Port 0 act as a USB device.
PWRON[16]
PA[1:0]
Boot Source Selection
00 = Boot from USB and pin PH.0 used as the USB0_VBUSVLD.
01 = Boor from eMMC and pin PC[5:0] or PI[10:5] used as the
eMMC functionality
1
.
10 = Boot from NAND Flash and pin PC[14:0] or PI[15:1] used as
the NAND functionality
2,3
.
11 = Boot from SPI Flash and pin PB[9:6] used as the SPI0
functionality.
Note 1: PC[5:0] used as the eMMC functionality in NUC972 while
PI[10:5] used as the eMMC functionality in NUC976 and NUC977.
Note 2: PC[14:0] used as the NAND functionality in NUC972 while
PI[15:1] used as the NAND functionality in NUC977.
Note 3: NUC976 doesn
’t support NAND interface.
PWRON[1:0]
PA.2
System Clock Source Selection
0 = System clock is from 12 MHz crystal.
1 = System clock is from UPLL output.
PWRON[2]
PA.3
Watchdog Timer (WDT) Enabled/Disabled Selection
0 = WDT Disabled after power-on.
1 = WDT Enabled after power-on.
PWRON[3]
PA.4
JTAG Interface ON/OFF Selection
0 = Pin PJ[4:0] used as GPIO pin.
1 = Pin PJ[4:0] used as JTAG interface.
PWRON[4]
PA.5
UART 0 Debug Message Output ON/OFF Selection
0 = UART 0 debug message output ON and pin PE[1:0] used as
the UART0 functionality.
1 = UART 0 debug message output OFF and pin PE[1:0] used as
the GPIO functionality.
PWRON[5]
PA[7:6]
NAND Flash Page Size selection
00 = NAND Flash page size is 2KB.
01 = NAND Flash page size is 4KB.
10 = NAND Flash page size is 8KB.
11 = Ignore Power-On Setting.
PWRON[7:6]