Data Sheet

356
8161D–AVR–10/09
ATmega48PA/88PA/168PA/328P
29.2.3 ATmega88PA: Supply Current of IO 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 ”Power Reduction Register” on page 42 for
details.
It is possible to calculate the typical current consumption based on the numbers from Table 29-4
on page 356 for other V
CC
and frequency settings than listed in Table 29-3 on page 356.
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 356, third column, we see that we need
to add 13.6% for the TIMER1, 26.3% for the ADC, and 21.5% for the SPI module. Reading from
Figure 29-52 on page 353, we find that the idle current consumption is ~0.027 mA at V
CC
= 2.0V
and F = 1MHz. The total current consumption in idle mode with TIMER1, ADC, and SPI enabled,
gives:
Table 29-3. ATmega88PA: Additional Current Consumption for the different I/O modules
(absolute values)
PRR bit Typical numbers
V
CC
= 2V, F = 1 MHz V
CC
= 3V, F = 4 MHz V
CC
= 5V, F = 8 MHz
PRUSART0 3.0 uA 21.3 uA 97.9 uA
PRTWI 6.1 uA 45.4 uA 219.0 uA
PRTIM2 5.2 uA 35.2 uA 149.5 uA
PRTIM1 3.8 uA 25.6 uA 110.0 uA
PRTIM0 1.5 uA 9.8 uA 39.6 uA
PRSPI 5.2 uA 40.0 uA 199.6 uA
PRADC 6.3 uA 48.7 uA 247.0 uA
Table 29-4. ATmega88PA: Additional Current Consumption (percentage) in Active and Idle
mode
PRR bit
Additional Current consumption
compared to Active with external
clock (see Figure 29-47 on page
351 and Figure 29-48 on page
351)
Additional Current consumption
compared to Idle with external
clock (see Figure 29-52 on page
353 and Figure 29-53 on page
354)
PRUSART0 1.8% 11.4%
PRTWI 3.9% 24.4%
PRTIM2 2.9% 18.6%
PRTIM1 2.1% 13.6%
PRTIM0 0.8% 5.2%
PRSPI 3.5% 21.5%
PRADC 4.2% 26.3%
ICCtotal 0.027 mA (1 + 0.136 + 0.263 + 0.215)⋅ 0.043 mA≈≈