LPC1777 View Datasheet(PDF) - NXP Semiconductors.
Part Name
Description
MFG CO.
LPC1777
NXP Semiconductors.
'LPC1777' PDF : 120 Pages View PDF
NXP Semiconductors
LPC178x/7x
32-bit ARM Cortex-M3 microcontroller
IRC oscillator
main oscillator
(osc_clk)
LPC178x/7x
MAIN PLL0
CLKSRCSEL
(system clock select)
ALT PLL1
pll_clk
sysclk
alt_pll_clk
sysclk
pll_clk
CCLKSEL
(CPU clock select)
CPU CLOCK
DIVIDER
EMC
CLOCK DIVIDER
cclk
emc_clk
Peripheral
pclk
CLOCK DIVIDER
sysclk
pll_clk
alt_pll_clk
USBCLKSEL
(USB clock select)
USB
CLOCK DIVIDER
usb_clk
Fig 7. LPC178x/7x clock generation block diagram
002aaf531
7.33.1.1 Internal RC oscillator
The IRC may be used as the clock that drives the PLL and subsequently the CPU. The
nominal IRC frequency is 12 MHz. The IRC is trimmed to 1 % accuracy over the entire
voltage and temperature range.
Upon power-up or any chip reset, the LPC178x/7x use the IRC as the clock source.
Software may later switch to one of the other available clock sources.
7.33.1.2 Main oscillator
The main oscillator can be used as the clock source for the CPU, with or without using the
PLL. The main oscillator also provides the clock source for the alternate PLL1.
The main 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 main
PLL. The clock selected as the PLL input is PLLCLKIN. The ARM processor clock
frequency is referred to as CCLK elsewhere in this document. The frequencies of
PLLCLKIN and CCLK are the same value unless the PLL is active and connected. The
clock frequency for each peripheral can be selected individually and is referred to as
PCLK. Refer to Section 7.33.2 for additional information.
LPC178X_7X
Product data sheet
All information provided in this document is subject to legal disclaimers.
Rev. 5.5 — 26 April 2016
© NXP Semiconductors N.V. 2016. All rights reserved.
61 of 126
Share Link: 