
UM10800
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© NXP Semiconductors N.V. 2016. All rights reserved.
User manual
Rev. 1.2 — 5 October 2016
35 of 487
NXP Semiconductors
UM10800
Chapter 5: LPC82x System configuration (SYSCON)
5.6.3 System PLL control register
This register connects and enables the system PLL and configures the PLL multiplier and
divider values. The PLL accepts an input frequency from 10 MHz to 25 MHz from various
clock sources. The input frequency is multiplied to a higher frequency and then divided
down to provide the actual clock used by the CPU, peripherals, and memories. The PLL
can produce a clock up to the maximum allowed for the CPU.
Remark:
The divider values for P and M must be selected so that the PLL output clock
frequency FCLKOUT is lower than 100 MHz.
14
I2C1_RST_N
I2C1 reset control
1
0
Assert the I2C1 reset.
1
Clear the I2C1 reset.
15
I2C2_RST_N
I2C2 reset control
1
0
Assert the I2C2 reset.
1
Clear the I2C2 reset.
16
I2C3_RST_N
I2C3 reset control
1
0
Assert the I2C3 reset.
1
Clear the I2C3 reset.
23:17
-
-
Reserved
-
24
ADC_RST_N
ADC reset control
1
0
Assert the ADC reset.
1
Clear the ADC reset.
28:25
-
-
Reserved
-
29
DMA_RST_N
DMA reset control
1
0
Assert the DMA reset.
1
Clear the DMA reset.
31:30
-
-
Reserved
-
Table 23.
Peripheral reset control register (PRESETCTRL, address 0x4004 8004) bit
description
Bit
Symbol
Value
Description
Reset
value
Table 24.
System PLL control register (SYSPLLCTRL, address 0x4004 8008) bit description
Bit
Symbol
Value
Description
Reset
value
4:0
MSEL
Feedback divider value. The division value M is the
programmed MSEL value + 1.
00000: Division ratio M = 1
to
11111: Division ratio M = 32
0