Datasheet

507
8272E–AVR–04/2013
ATmega164A/PA/324A/PA/644A/PA/1284/P
29.7.3 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-
12 on page 481 for other V
CC
and frequency settings than listed in Table 29-11 on page 481.
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 29-12 on page 481, third column, we see that we need
to add 8.0% for the TIMER1, 19.8% for the ADC, and 13.2% for the SPI module. Reading from
Figure 29-301 on page 505, we find that the idle current consumption is ~0.075mA at V
CC
= 2.0V
and F = 1MHz. The total current consumption in idle mode with TIMER1, ADC, and SPI enabled,
gives:
Table 29-13. 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 3.0µA 19.2µA 87.7µA
PRUSART0 2.9µA 19.2µA 88.5µA
PRTWI 7.5µA 49.3µA 230.3µA
PRTIM3 4.0µA 24.7µA 105.5µA
PRTIM2 6.0µA 39.7µA 176.3µA
PRTIM1 4.2µA 26.4µA 113.7µA
PRTIM0 1.7µA 11.6µA 54.3µA
PRADC 13.5µA 54.7µA 273µA
PRSPI 5.7µA 40.6µA 212.2µA
Table 29-14. Additional current consumption (percentage) in Active and Idle mode.
PRR bit
Additional current consumption
compared to Active with external
clock (see Figure 29-295 on page 502
and Figure 29-296 on page 502)
Additional current consumption
compared to Idle with external clock
(see Figure 29-300 on page 504 and
Figure 29-301 on page 505)
PRUSART1 0.9% 6.0%
PRUSART0 0.9% 6.0%
PRTWI 2.3% 15.4%
PRTIM3 1.1% 7.5%
PRTIM2 1.8% 12.1%
PRTIM1 1.2% 8.0%
PRTIM0 0.5% 3.6%
PRTADC 3.0% 19.8%
PRSPI 2.0% 13.2%
ICCtotal 0.075mA (1+ 0.08 + 0.198 + 0.132) 0.106mA