
UM10800
All information provided in this document is subject to legal disclaimers.
© NXP Semiconductors N.V. 2016. All rights reserved.
User manual
Rev. 1.2 — 5 October 2016
36 of 487
NXP Semiconductors
UM10800
Chapter 5: LPC82x System configuration (SYSCON)
5.6.4 System PLL status register
This register is a Read-only register and supplies the PLL lock status (see
5.6.5 System oscillator control register
This register configures the frequency range for the system oscillator. The system
oscillator itself is powered on or off in the PDRUNCFG register. See
.
5.6.6 Watchdog oscillator control register
This register configures the watchdog oscillator. The oscillator consists of an analog and a
digital part. The analog part contains the oscillator function and generates an analog clock
(Fclkana). With the digital part, the analog output clock (Fclkana) can be divided to the
6:5
PSEL
Post divider ratio P. The division ratio is 2
P.
0
0x0
P = 1
0x1
P = 2
0x2
P = 4
0x3
P = 8
31:7
-
-
Reserved. Do not write ones to reserved bits.
-
Table 24.
System PLL control register (SYSPLLCTRL, address 0x4004 8008) bit description
Bit
Symbol
Value
Description
Reset
value
Table 25.
System PLL status register (SYSPLLSTAT, address 0x4004 800C) bit description
Bit
Symbol
Value
Description
Reset
value
0
LOCK
PLL lock status
0
0
PLL not locked
1
PLL locked
31:1
-
-
Reserved
-
Table 26.
System oscillator control register (SYSOSCCTRL, address 0x4004 8020) bit
description
Bit
Symbol
Value
Description
Reset
value
0
BYPASS
Bypass system oscillator
0x0
0
Disabled. Oscillator is not bypassed.
1
Enabled. PLL input (sys_osc_clk) is fed directly
from the XTALIN pin bypassing the oscillator. Use
this mode when using an external clock source
instead of the crystal oscillator.
1
FREQRANGE
Determines oscillator frequency range.
0x0
0
1 - 20 MHz frequency range.
1
15 - 25 MHz frequency range
31:2
-
-
Reserved
0x00