Datasheet

429
8272E–AVR–04/2013
ATmega164A/PA/324A/PA/644A/PA/1284/P
29.4.3 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 29-8
on page 429 for other V
CC
and frequency settings than listed in Table 29-7 on page 429.
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 29-8 on page 429, third column, we see that we need
to add 6.0% for the TIMER1, 14.8% for the ADC, and 10.3% for the SPI module. Reading from
Figure 29-153 on page 426, we find that the idle current consumption is ~0.078mA at V
CC
= 2.0V
and F = 1MHz. The total current consumption in idle mode with TIMER1, ADC, and SPI enabled,
gives:
Table 29-7. Additional current consumption for the different I/O modules (absolute values).
PRR bit Typical numbers in
V
CC
= 2V, F = 1MHz V
CC
= 3V, F = 4MHz V
CC
= 5V, F = 8MHz
PRUSART1 3.1µA 21.5µA 100.0µA
PRUSART0 3.0µA 21.0µA 98.2µA
PRTWI 6.4µA 45.7µA 214.5µA
PRTIM2 5.6µA 37.7µA 165.8µA
PRTIM1 3.6µA 24.8µA 107.0µA
PRTIM0 1.7µA 10.4µA 43.2µA
PRADC 11.8µA 59.2µA 257.0µA
PRSPI 5.3µA 40.1µA 206.8µA
Table 29-8. Additional current consumption (percentage) in Active and Idle mode.
PRR bit
Additional current consumption
compared to Active with external
clock (see Figure 29-148 on page
424 and Figure 29-149 on page
424)
Additional current consumption
compared to Idle with external
clock (see Figure 29-153 on page
426 and Figure 29-154 on page
427)
PRUSART1 1.4% 5.3%
PRUSART0 1.4% 5.2%
PRTWI 3.0% 11.3%
PRTIM2 2.5% 9.1%
PRTIM1 1.6% 6.0%
PRTIM0 0.7% 2.5%
PRADC 4.2% 14.8%
PRSPI 2.7% 10.3%
ICCtotal 0.078mA (1+ 0.060 + 0.148 + 0.103) 0.102mA