C868_02 Datasheet, PDF (223/244 Pages) Infineon Technologies AG – 8 - Bit CMOS Microcontroller

C868
Power Saving Modes
8
Power Saving Modes
The C868 provides two basic power saving modes, the idle mode and the power down
mode. Additionally, a slow down mode is available. This power saving mode reduces the
internal clock rate in normal operating mode and it can also be used for further power
reduction in idle mode. Further power saving is possible in the normal, idle and slow
down modes by disabling unutilized peripherals. The peripherals that has the power-
down capability are the timer/counter2, capture/compare unit and the A/D converter.
8.1
Power Saving Mode Control Registers
The functions of the power saving modes are controlled by bits which are located in the
special function registers PCON and PMCON0.
The bits PDE and IDLE located in SFR PCON select the power down mode or the idle
mode, respectively. If the power down mode and the idle mode are set at the same time,
power down mode takes precedence. Furthermore, register PCON contains two general
purpose flags. For example, the flag bits GF0 and GF1 can be used to give an indication
if an interrupt occurred during normal operation or during idle mode. For this, an
instruction that activates idle mode can also set one or both flag bits. When idle mode is
terminated by an interrupt, the interrupt service routine can examine the flag bits.
User’s Manual
8-1
V 0.4, 2002-01