Atmel ATSAM3N-EK Data Sheet
Evaluation Kit Hardware
SAM3N-EK Development Board User Guide
4-3
11080C–ATARM–30-Mar-11
4.3.3
Clock Circuitry
The clock generator of a SAM3N microcontroller is made up of:
A Low Power 32,768 Hz Slow Clock Oscillator with bypass mode
A Low Power RC Oscillator
A 3 to 20 MHz Crystal Oscillator, which can be bypassed
A factory programmed fast internal RC Oscillator. 3 output frequencies can be selected: 4 (default
value), 8 or 12 MHz.
value), 8 or 12 MHz.
A 60 to 130 MHz programmable PLL (input from 3.5 to 20 MHz), capable to provide the clock MCK to
the processor and to the peripherals.
the processor and to the peripherals.
The SAM3N-EK board is equipped with one 12 MHz crystal, and one 32.768 Hz crystal. An optional
12 MHz Piezoelectric Ceramic Resonator can be mounted in place of the 12 MHz crystal (for low cost
clocking option evaluation).
12 MHz Piezoelectric Ceramic Resonator can be mounted in place of the 12 MHz crystal (for low cost
clocking option evaluation).
Figure 4-3.
SAM3N MCU
4.3.4
Reset Circuitry
The on-board NRST button BP1 provides the SAM3N4C with external reset control.
Two User buttons BP2 and BP3, can be used to wake up the chip from low power modes.
The NRST pin is bidirectional. It is handled by the on-chip reset controller. It can be driven low to provide
a reset signal out to the external components. Conversely, it can be asserted low from the outside to
reset the microcontroller, its core and peripherals, with exception of the backup region (RTC, RTT and
a reset signal out to the external components. Conversely, it can be asserted low from the outside to
reset the microcontroller, its core and peripherals, with exception of the backup region (RTC, RTT and
DNP
XIN
PB2
PB3
PB10
PB11
PB4
PB6
PB7
PB5
PB6
PB7
PB5
NRST
PB1
PA0
PA1
PA2
PA3
PA4
PA5
PA6
PA1
PA2
PA3
PA4
PA5
PA6
PA9
PA10
PA11
PA12
PA13
PA14
PA15
PA16
PA17
PA18
PA19
PA20
PA21
PA22
PA23
PA24
PA25
PA26
PA27
PA28
PA29
PA30
PA31
PA10
PA11
PA12
PA13
PA14
PA15
PA16
PA17
PA18
PA19
PA20
PA21
PA22
PA23
PA24
PA25
PA26
PA27
PA28
PA29
PA30
PA31
P
C0
PC
1
PC
2
P
C3
PC
4
PC
5
PC
6
PC
7
P
C8
PC
9
P
C
10
P
C1
1
PC
12
PC
13
P
C
14
P
C1
5
PC
16
P
C1
7
P
C
18
PC
19
PC
20
PC
21
P
C2
2
PC
23
PC
24
PC
25
P
C2
6
P
C
27
P
C2
8
P
C
29
PC
30
PC
31
XOUT
XOUT32
PB0
JTAGSEL
XIN32
PB0
PB6
PB7
PB10
PB11
PB7
PB10
PB11
PB1
PB2
PB2
PB12
PB3
PB14
PB13
PB4
PB5
PB5
PB13
PB14
PB12
XIN32
XOUT32
XOUT32
PA7
PA8
PA8
ADVREF
DGND
DGND
VDDIO
DGND
DGND
DGND
VDDPLL
VDDCORE
DGND
VDDIN
VDDOUT
DGND
DGND
+3V3
+3V3
+3V3
PA[0..31]
PC[0..31]
PB[0..14]
NRST
R1
DNP
R1
DNP
C2
2
4.
7u
F
C2
2
4.
7u
F
C
13
100nF
C
13
100nF
R9
DNP
R9
DNP
C
7
100nF
C
7
100nF
C3
7pF
C3
7pF
R2
0R
R2
0R
C2
1
4.
7uF
C2
1
4.
7uF
C
10
100nF
C
10
100nF
C4
7pF
C4
7pF
C2
0
100nF
C2
0
100nF
C
15
100nF
C
15
100nF
Y1
Y1
1
2
3
C
19
100nF
C
19
100nF
JP3
JP3
JP2
JP2
C
12
100nF
C
12
100nF
Y3
32.768KHz
32.768KHz
Y3
32.768KHz
32.768KHz
1
2
3
4
C
18
100nF
C
18
100nF
R7
DNP
R7
DNP
C9
2.
2uF
C9
2.
2uF
C1
7
100nF
C1
7
100nF
C5
100nF
100nF
C5
100nF
100nF
SAM3N - LQFP100
MN1
SAM3N4C-AU
SAM3N4C-AU
SAM3N - LQFP100
MN1
SAM3N4C-AU
SAM3N4C-AU
PA0_PWM0_TIOA0
74
PA1_PWM1_TIOB0
72
PA2_PWM2_SCK0_DATRG
67
PA3_TWD0_NPCS3
66
PA4_TWCK0_TCLK0
55
PA5_RXD0_NPCS3
53
PA6_TXD0_PCKO
52
PA7_RTS0_PWM3
49
PA8_CTS0_ADTRG
48
PA9_URXD0_NPCS1
46
PA10_UTXD0_NPCS2
44
PA11_NPCS0_PWM0
42
PA12_MISO_PWM1
41
PA13_MOSI_PWM2
33
PA14_SPCK_PWM3
31
PA15_TIOA1
30
PA16_TIOB1
28
PA17_PCK1_AD0
12
PA18_PCK2_AD1
14
PA19_AD2
18
PA20_AD3
24
PA21_RXD1_PCK1_AD8
15
PA22_TXD1_NPCS3_AD9
20
PA23_SCK1_PWM0
22
VDDCORE
85
JTAGSEL
77
GND
45
GND
95
GND
70
GND
26
VDDIO
27
VDDIO
69
VDDIO
91
PB8_XOUT
96
PB9_XIN
97
PB0_PWM0_AD4
3
NRST
60
VDDCORE
56
ADVREF
1
PA25_CTS1_PWM2
38
PA24_RTS1_PWM1
34
PB2_URXD1_NPCS2_AD6
7
PB3_UTXD1_PCK2_AD7
9
PB6_TMS_SWDIO
79
PB4_TWD1_PWM2_TDI
51
PB5_TWCK1_TDO_TACESWO
76
PB7_TCK_SWCLK
83
TEST
61
PB12_ERASE
87
PB14_NPCS1_PWM3
99
VDDOUT
11
PB1_PWM1_AD5
5
PA26_TIOA2
39
PA27_TIOB2
57
PA28_TCLK1
59
PA29_TCLK2
63
PA30_NPCS2
64
PA31_NPCS1_PCK2
81
VDDIN
10
PB10_DDM
88
PB11_DDP
89
PB13_PCK0_DAC0
93
VDDIO
98
VDDCORE
36
VDDCORE
16
VDDPLL
100
VDDIO
50
GND
2
PC0
25
PC1
47
PC2
43
PC3
40
PC4_NPCS1
37
PC5
35
PC6
32
PC7_NPCS2
29
PC8_PWM0
58
PC9_PWM1
62
PC10_PWM2
65
PC11_PWM3
68
PC12_AD12
23
PC13_AD10
21
PC14_PCK2
71
PC15_AD11
19
PC16_PCK0
73
PC17_PCK1
75
PC18_PWM0
78
PC19_PWM1
80
PC20_PWM2
82
PC21_PWM3
84
PC22_PWM0
86
PC23_TIOA3
90
PC24_TIOB3
92
PC25_TCLK3
94
PC26_TIOA4
13
PC27_TIOB4
17
PC28_TCLK4
54
PC29_TIOA5_AD13
4
PC30_TIOB5_AD14
6
PC31_TCLK5_AD15
8
R5
0R
R5
0R
C1
4
D
NP
C1
4
D
NP
C
8
100nF
C
8
100nF
Y2
12MHz
Y2
12MHz
C1
15pF
C1
15pF
C
16
100nF
C
16
100nF
R4
DNP
R4
DNP
R3
0R
R3
0R
R10
0R
R10
0R
JP1
DNP
JP1
DNP
C2
15pF
C2
15pF
C
11
100nF
C
11
100nF