Datasheet

ATmega48A/PA/88A/PA/168A/PA/328/P
 2018 Microchip Technology Inc. Data Sheet Complete DS40002061A-page 482
31.7.3 ATmega328 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 51 for details.
It is possible to calculate the typical current consumption based on the numbers from Table 31-13 for other V
CC
and frequency settings than listed in Table 31-14.
31.7.3.1 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 31-14, third column, we see that we need to add 14.5% for the TIMER1, 22.1% for
the ADC, and 15.7% for the SPI module. Reading from Figure 31-338 on page 504, we find that the idle current
consumption is ~0.055 mA at V
CC
= 2.0V and F = 1MHz. The total current consumption in idle mode with
TIMER1, ADC, and SPI enabled, gives:
Table 31-13. ATmega328: 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
PRUSART0 3.20 µA 22.17 µA 100.25 µA
PRTWI 7.34 µA 46.55 µA 199.25 µA
PRTIM2 7.34 µA 50.79 µA 224.25 µA
PRTIM1 6.19 µA 41.25 µA 176.25 µA
PRTIM0 1.89 µA 14.28 µA 61.13 µA
PRSPI 6.94 µA 43.84 µA 186.50 µA
PRADC 8.66 µA 61.80 µA 295.38 µA
Table 31-14. ATmega328: Additional Current Consumption (percentage) in Active and Idle mode
PRR bit
Additional Current consumption
compared to Active with external
clock (see Figure 31-332 on page
501 and Figure 31-333 on page
502)
Additional Current consumption
compared to Idle with external
clock (see Figure 31-337 on page
504 and Figure 31-338 on page
504)
PRUSART0 1.4% 7.8%
PRTWI 3.0% 16.6%
PRTIM2 3.3% 17.8%
PRTIM1 2.7% 14.5%
PRTIM0 0.9% 4.8%
PRSPI 2.9% 15.7%
PRADC 4.1% 22.1%
ICCtotal 0.045 mA (1 + 0.145 + 0.221 + 0.157) 0.069 mA