Datasheet

Product data sheet Rev. 9.2 — 26 March 2014 54 of 127

NXP Semiconductors

LPC1110/11/12/13/14/15

32-bit ARM Cortex-M0 microcontroller

The system oscillator operates at frequencies of 1 MHz to 25 MHz. This frequency can be

boosted to a higher frequency, up to the maximum CPU operating frequency, by the

system PLL.

7.16.1.3 Watchdog oscillator

The watchdog oscillator can be used as a clock source that directly drives the CPU, the

watchdog timer, or the CLKOUT pin. The watchdog oscillator nominal frequency is

programmable between 9.4 kHz and 2.3 MHz. The frequency spread over processing and

temperature is 40 %.

7.16.2 System PLL

The PLL accepts an input clock frequency in the range of 10 MHz to 25 MHz. The input

frequency is multiplied up to a high frequency with a Current Controlled Oscillator (CCO).

The multiplier can be an integer value from 1 to 32. The CCO operates in the range of

156 MHz to 320 MHz, so there is an additional divider in the loop to keep the CCO within

its frequency range while the PLL is providing the desired output frequency. The PLL

output frequency must be lower than 100 MHz. The output divider may be set to divide by

2, 4, 8, or 16 to produce the output clock. Since the minimum output divider value is 2, it is

insured that the PLL output has a 50 % duty cycle. The PLL is turned off and bypassed

following a chip reset and may be enabled by software. The program must configure and

activate the PLL, wait for the PLL to lock, and then connect to the PLL as a clock source.

The PLL settling time is 100 s.

7.16.3 Clock output

The LPC1110/11/12/13/14/15 features a clock output function that routes the IRC

oscillator, the system oscillator, the watchdog oscillator, or the main clock to an output pin.

7.16.4 Wake-up process

The LPC1110/11/12/13/14/15 begin operation at power-up and when awakened from

Deep power-down mode by using the 12 MHz IRC oscillator as the clock source. This

allows chip operation to resume quickly. If the system oscillator or the PLL is needed by

the application, software will need to enable these features and wait for them to stabilize

before they are used as a clock source.

7.16.5 Power control

The LPC1110/11/12/13/14/15 support a variety of power control features. There are three

special modes of processor power reduction: Sleep mode, Deep-sleep mode, and Deep

power-down mode. The CPU clock rate may also be controlled as needed by changing

clock sources, reconfiguring PLL values, and/or altering the CPU clock divider value. This

allows a trade-off of power versus processing speed based on application requirements.

In addition, a register is provided for shutting down the clocks to individual on-chip

peripherals, allowing fine tuning of power consumption by eliminating all dynamic power

use in any peripherals that are not required for the application. Selected peripherals have

their own clock divider which provides even better power control.

7.16.5.1 Power profiles (LPC1100L and LPC1100XL series only)

The power consumption in Active and Sleep modes can be optimized for the application

through simple calls to the power profile. The power configuration routine configures the

LPC1110/11/12/13/14/15 for one of the following power modes: