Datasheet

351
8272E–AVR–04/2013
ATmega164A/PA/324A/PA/644A/PA/1284/P
29.1.3 Supply current of I/O modules
The tables and formulas below can be used to calculate the additional current consumption for
the different I/O modules in Active and Idle mode. The enabling or disabling of the I/O modules
are controlled by the Power Reduction Register. See ”PRR0 – Power Reduction Register 0” on
page 48 for details.
It is possible to calculate the typical current consumption based on the numbers from Table 29-4
on page 377 for other V
CC
and frequency settings than listed in Table 29-3 on page 377.
Example Calculate the expected current consumption in idle mode with TIMER1, ADC, and SPI enabled
at V
CC
= 2.0V and F = 1MHz. From Table 29-4 on page 377, third column, we see that we need
to add 8.8% for the TIMER1, 20.9% for the ADC, and 13.8% for the SPI module. Reading from
Figure 29-55 on page 374, we find that the idle current consumption is ~0.073mA at V
CC
= 2.0V
and F = 1MHz. The total current consumption in idle mode with TIMER1, ADC, and SPI enabled,
gives:
Table 29-1. Additional current consumption for the different I/O modules (absolute values).
PRR bit Typical numbers
V
CC
= 2V, F = 1MHz V
CC
= 3V, F = 4MHz V
CC
= 5V, F = 8MHz
PRUSART1 3.1µA 20.9µA 96.7µA
PRUSART0 2.9µA 21.6µA 101µA
PRTWI 6.1µA 44µA 205.8µA
PRTIM2 5.9µA 40.1µA 182µA
PRTIM1 3.7µA 26.1µA 113.2µA
PRTIM0 1.4µA 9.4µA 38.8µA
PRADC 11.7µA 55.5µA 249.5µA
PRSPI 5.1µA 37.9µA 195.5µA
Table 29-2. Additional current consumption (percentage) in Active and Idle mode.
PRR bit
Additional current consumption
compared to Active with external
clock (see Figure 29-50 on page
372 and Figure 29-51 on page
372)
Additional current consumption
compared to Idle with external
clock (see Figure 29-55 on page
374 and Figure 29-56 on page
375)
PRUSART1 1.5
% 7.4%
PRUSART0 1.5% 7.5%
PRTWI 3.2% 15.4%
PRTIM2 2.9% 14.0%
PRTIM1 1.8% 8.8%
PRTIM0 0.7% 3.1%
PRADC 4.4% 20.9%
PRSPI 2.9% 13.8%
ICCtotal 0.073 mA (1+ 0.088 + 0.209 + 0.138) 0.10 mA