© Koninklijke Philips Electronics N.V. 2006. All rights reserved.
User manual
Rev. 01 — 12 January 2006
32
Philips Semiconductors
UM10161
Volume 1
Chapter 3: System control block
[1]
Reset value reflects the data stored in used bits only. It does not include reserved bits content.
3.9.2 Power
Control
register (PCON - 0xE01F COCO)
The PCON register contains two bits. Writing a one to the corresponding bit causes entry
to either the Power-down or Idle mode. If both bits are set, Power-down mode is entered.
3.9.3 Power Control for Peripherals register (PCONP - 0xE01F COC4)
The PCONP register allows turning off selected peripheral functions for the purpose of
saving power. This is accomplished by gating off the clock source to the specified
peripheral blocks. A few peripheral functions cannot be turned off (i.e. the watchdog timer,
GPIO, the Pin Connect block, and the System Control block). Some peripherals,
particularly those that include analog functions, may consume power that is not clock
dependent. These peripherals may contain a separate disable control that turns off
additional circuitry to reduce power. Each bit in PCONP controls one of the peripherals.
The bit numbers correspond to the related peripheral number as shown in the APB
peripheral map
Table 2 “APB peripheries and base addresses”
.
If a peripheral control bit is 1, that peripheral is enabled. If a peripheral bit is 0, that
peripheral is disabled to conserve power. For example if bit 19 is 1, the I
2
C1 interface is
enabled. If bit 19 is 0, the I
2
C1 interface is disabled.
Important: valid read from a peripheral register and valid write to a peripheral
register is possible only if that peripheral is enabled in the PCONP register!
Table 24:
Power control registers
Name
Description
Access Reset
value
Address
PCON
Power Control Register. This register contains
control bits that enable the two reduced power
operating modes of the microcontroller. See
.
R/W
0x00
0xE01F C0C0
PCONP Power Control for Peripherals Register. This
register contains control bits that enable and
disable individual peripheral functions,
Allowing elimination of power consumption by
peripherals that are not needed.
R/W
0x0018 17BE
0xE01F C0C4
Table 25:
Power Control register (PCON - address 0xE01F COCO) bit description
Bit
Symbol
Description
Reset
value
0
IDL
Idle mode - when 1, this bit causes the processor clock to be stopped,
while on-chip peripherals remain active. Any enabled interrupt from a
peripheral or an external interrupt source will cause the processor to
resume execution.
0
1
PD
Power-down mode - when 1, this bit causes the oscillator and all
on-chip clocks to be stopped. A wake-up condition from an external
interrupt can cause the oscillator to restart, the PD bit to be cleared,
and the processor to resume execution.
0
7:2
-
Reserved, user software should not write ones to reserved bits. The
value read from a reserved bit is not defined.
NA