LPC5411x
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© NXP Semiconductors N.V. 2018. All rights reserved.
Product data sheet
Rev. 2.1 — 9 May 2018
27 of 105
NXP Semiconductors
LPC5411x
32-bit ARM Cortex-M4/M0+ microcontroller
7.13 System control
7.13.1 Clock sources
The LPC5411x supports two external and three internal clock sources:
•
The Free Running Oscillator (FRO).
•
Watchdog oscillator (WDTOSC).
•
External clock source from the digital I/O pin CLKIN.
•
External RTC 32.768 kHz clock.
•
Output of the system PLL.
7.13.1.1
FRO
The internal FRO can be used as a CPU clock or a clock source to the system PLL. On
power-up, or any chip reset, the LPC5411x uses an internal 12 MHz FRO as the clock
source. Software may later switch to one of the available clock sources. A selectable 48
MHz or 96 MHz FRO is also available as a clock source.
The 48 MHz FRO can be used as a clock source to the USB.
The FRO is trimmed to
1 % accuracy over the entire voltage and temperature range.
7.13.1.2
Watchdog oscillator (WDTOSC)
The watchdog oscillator is a low-power internal oscillator. The WDTOSC can be used to
provide a clock to the WWDT and to the entire chip. The watchdog oscillator has a
selectable frequency in the range of 6 kHz to 1.5 MHz.
Fig 7.
LPC5411x APB Memory map
31-21
20
19-13
12
11-9
8
7-0
0x4003 FFFF
0x4003 5000
0x4003 4000
0x4002 D000
0x4002 C000
0x4002 9000
0x4002 8000
0x4002 0000
(reserved)
(reserved)
(reserved)
(reserved)
RTC
Flash controller
CTIMER 2
APB bridge 1
31-15
14
13
12
11-10
9
8
0x4001 FFFF
0x4000 F000
0x4000 E000
0x4000 D000
0x4000 C000
0x4000 A000
0x4000 9000
0x4000 8000
0x4000 6000
0x4000 5000
0x4000 4000
0x4000 3000
0x4000 2000
0x4000 1000
0x4000 0000
(reserved)
Multi-rate timer
(reserved)
CTIMER 0
Watchdog timer
Micro-tick timer
CTIMER 1
APB bridge 0
7-6
5
4
3
2
1
Input muxes
GINT 1
IOCON
Pin Interrupts (PINT)
(reserved)
GINT 0
2
Syscon
31-10
9
8
7-1
0
0x4005 FFFF
0x4004 A000
0x4004 9000
0x4004 8000
0x4004 1000
0x4004 0000
(reserved)
CTIMER 3
Asynch. Syscon
(reserved)
CTIMER 4
Asynchronous APB bridge
aaa-016687