Infineon XC800 Series, Руководство пользователя

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AP08056
Power Saving Features
A Timer 2 Example
Application Note 23 V1.0, 2006-12
8 A Timer 2 Example
In this section, the XC866-4FR device and the XC888 device were configured to start
timer 2 in auto-reload mode which generates an overflow in every 20 ms. The overflow
will trigger an interrupt service routine that will toggle port 3.0. The current drawn by the
devices in active, idle, slow-down, slow-down-idle and prescaler mode were measured.
8.1 Active and Idle Mode Current
The current drawn by the devices in active mode (i.e. device wait in an endless loop for
the interrupt event) and idle is shown in the table below. It can be observed that the
savings (“Difference”) that can be achieved by putting the device in idle mode is
comparable to
Table 1 .
8.2 Slow-Down and Slow-Down-Idle Current
The program is now programmed to run in slow-down mode and slow-down-idle mode.
For every different slow-down factor, the timer reload value was changed accordingly
such that the timer will overflow in every 20 ms.
Table 15 Current consumed by devices when timer 2 is active
Product CPU Clock Active Idle Difference
XC866-4FR 26.61 MHz 18.04 mA 14.23 mA 3.64 mA
XC888 24.125 MHz 24.00 mA 20.01 mA 3.59 mA
Table 16 Current consumed by XC866-4FR device when timer 2 is active
f
SYS
= 79.84 MHz Current (mA)
Peripheral
Frequency (MHz) CLKREL Slow-Down
(X)
Slow-Down-
Idle (Y)
Difference
1)
X - Y
26.613 0000
B
18.04 14.23 3.81
6.653 0010
B
8.69 7.76 0.93
1.663 0100
B
6.23 6.07 0.16
0.832 0101
B
5.82 5.80 0.02
0.416 0110
B
5.62 5.66 -0.04
0.208 0111
B
5.51 5.59 -0.08
0.104 1000
B
5.46 5.55 -0.09