UM10503
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© NXP B.V. 2012. All rights reserved.
User manual
Rev. 1.3 — 6 July 2012
139 of 1269
12.1 How to read this chapter
Remark:
The VADC is not available on parts LPC4350/30/20/10.
Flash/EEPROM, Ethernet, USB0, USB1, and LCD-related clocks are not available on all
packages. See
.
12.2 Basic configuration
The CCU1/2 are configured as follows:
•
See
for clocking and power control.
•
All branch clocks are enabled by default.
•
Do not reset the CCUs during normal operation.
•
Configure the output clock for the EMC clock divider (
) together with bit 16 in
the CREG6 register (
).
12.3 Features
The CCUs switch the clocks to individual peripherals on or off.
•
Auto mode activates the AHB disable protocol before switching off the branch clock.
•
In Wake-up mode, clocks can be selected to run automatically after a wake-up event.
12.4 General description
Each CGU base clock has several clock branches which can be turned on or off
independently by the Clock Control Units CCU1 or CCU2. The branch clocks are
distributed between CCU1 and CCU2.
UM10503
Chapter 12: LPC43xx Clock Control Unit (CCU)
Rev. 1.3 — 6 July 2012
User manual
Table 97.
CCU clocking and power control
Base clock
Branch clock
Operating frequency
CCU1
BASE_M4_CLK
CLK_M4_BUS
up to 204 MHz
CCU2
BASE_M4_CLK
CLK_M4_BUS
up to 204 MHz