© Koninklijke Philips Electronics N.V. 2005. All rights reserved.
User manual
Rev. 01 — 15 August 2005
28
Philips Semiconductors
UM10139
Volume 1
Chapter 3: System Control Block
the microcontroller. The same concern is present with the PLL1 and the USB. The
protection is accomplished by a feed sequence similar to that of the Watchdog Timer.
Details are provided in the description of the PLLFEED register.
Both PLLs are turned off and bypassed following a chip Reset and when by entering
Power-down mode. The PLL is enabled by software only. The program must configure and
activate the PLL, wait for the PLL to Lock, then connect to the PLL as a clock source.
3.8.1 Register
description
The PLL is controlled by the registers shown in
. More detailed descriptions
follow.
Warning: Improper setting of the PLL0 and PLL1 values may result in incorrect
operation of the device and the USB module!
[1]
Reset value reflects the data stored in used bits only. It does not include reserved bits content.
Table 15:
PLL registers
Generic
name
Description
Access Reset
value
System clock
(PLL0)
Address & Name
USB 48 MHz
clock (PLL1)
Address & Name
PLLCON
PLL Control Register. Holding register for
updating PLL control bits. Values written to this
register do not take effect until a valid PLL feed
sequence has taken place.
R/W
0
0xE01F C080
PLL0CON
0xE01F C0A0
PLL1CON
PLLCFG
PLL Configuration Register. Holding register for
updating PLL configuration values. Values
written to this register do not take effect until a
valid PLL feed sequence has taken place.
R/W
0
0xE01F C084
PLL0CFG
0xE01F C0A4
PLL1CFG
PLLSTAT
PLL Status Register. Read-back register for PLL
control and configuration information. If
PLLCON or PLLCFG have been written to, but a
PLL feed sequence has not yet occurred, they
will not reflect the current PLL state. Reading
this register provides the actual values
controlling the PLL, as well as the status of the
PLL.
RO
0
0xE01F C088
PLL0STAT
0xE01F C0A8
PLL1STAT
PLLFEED
PLL Feed Register. This register enables
loading of the PLL control and configuration
information from the PLLCON and PLLCFG
registers into the shadow registers that actually
affect PLL operation.
WO
NA
0xE01F C08C
PLL0FEED
0xE01F C0AC
PLL1FEED