© Koninklijke Philips Electronics N.V. 2005. All rights reserved.
User manual
Rev. 01 — 15 August 2005
30
Philips Semiconductors
UM10139
Volume 1
Chapter 3: System Control Block
The PLL must be set up, enabled, and Lock established before it may be used as a clock
source. When switching from the oscillator clock to the PLL output or vice versa, internal
circuitry synchronizes the operation in order to ensure that glitches are not generated.
Hardware does not insure that the PLL is locked before it is connected or automatically
disconnect the PLL if lock is lost during operation. In the event of loss of PLL lock, it is
likely that the oscillator clock has become unstable and disconnecting the PLL will not
remedy the situation.
3.8.3 PLL Configuration register (PLL0CFG - 0xE01F C084, PLL1CFG -
0xE01F C0A4)
The PLLCFG register contains the PLL multiplier and divider values. Changes to the
PLLCFG register do not take effect until a correct PLL feed sequence has been given (see
Section 3.8.7 “PLL Feed register (PLL0FEED - 0xE01F C08C, PLL1FEED -
0xE01F C0AC)” on page 32
). Calculations for the PLL frequency, and multiplier and
divider values are found in the PLL Frequency Calculation section on page 33.
Table 16:
PLL Control register (PLL0CON - address 0xE01F C080, PLL1CON - address
0xE01F C0A0) bit description
Bit
Symbol
Description
Reset
value
0
PLLE
PLL Enable. When one, and after a valid PLL feed, this bit will
activate the PLL and allow it to lock to the requested frequency. See
PLLSTAT register,
0
1
PLLC
PLL Connect. When PLLC and PLLE are both set to one, and after a
valid PLL feed, connects the PLL as the clock source for the
microcontroller. Otherwise, the oscillator clock is used directly by the
microcontroller. See PLLSTAT register,
0
7:2
-
Reserved, user software should not write ones to reserved bits. The
value read from a reserved bit is not defined.
NA
Table 17:
PLL Configuration register (PLL0CFG - address 0xE01F C084, PLL1CFG - address
0xE01F C0A4) bit description
Bit
Symbol
Description
Reset
value
4:0
MSEL
PLL Multiplier value. Supplies the value "M" in the PLL frequency
calculations.
Note: For details on selecting the right value for MSEL see
3.8.9 “PLL frequency calculation” on page 33
0
6:5
PSEL
PLL Divider value. Supplies the value "P" in the PLL frequency
calculations.
Note: For details on selecting the right value for PSEL see
3.8.9 “PLL frequency calculation” on page 33
0
7
-
Reserved, user software should not write ones to reserved bits. The
value read from a reserved bit is not defined.
NA