ATmega48PA/88PA/168PA/328P
29.4.3
ATmega328P 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.
Table 29-7. ATmega328P: Additional Current Consumption for the different I/O modules
(absolute values)
PRR bit
Typical numbers
VCC = 2V, F = 1MHz
3.20 µA
VCC = 3V, F = 4MHz
22.17 µA
VCC = 5V, F = 8MHz
100.25 µA
PRUSART0
PRTWI
7.34 µA
46.55 µA
199.25 µA
PRTIM2
PRTIM1
PRTIM0
PRSPI
7.34 µA
50.79 µA
224.25 µA
6.19 µA
41.25 µA
176.25 µA
1.89 µA
14.28 µA
61.13 µA
6.94 µA
43.84 µA
186.50 µA
PRADC
8.66 µA
61.80 µA
295.38 µA
Table 29-8. ATmega328P: Additional Current Consumption (percentage) in Active and Idle
mode
Additional Current consumption
compared to Active with external
clock (see Figure 29-139 on page
399 and Figure 29-140 on page
399)
Additional Current consumption
compared to Idle with external
clock (see Figure 29-144 on page
401 and Figure 29-145 on page
402)
PRR bit
PRUSART0
PRTWI
1.4 %
3.0 %
3.3 %
2.7 %
0.9 %
2.9 %
4.1 %
7.8%
16.6 %
17.8 %
14.5 %
4.8 %
PRTIM2
PRTIM1
PRTIM0
PRSPI
15.7 %
22.1 %
PRADC
It is possible to calculate the typical current consumption based on the numbers from Table 29-8
on page 404 for other VCC and frequency settings than listed in Table 29-7 on page 404.
Example
Calculate the expected current consumption in idle mode with TIMER1, ADC, and SPI enabled
at VCC = 2.0V and F = 1MHz. From Table 29-8 on page 404, 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 29-145 on page 402, we find that the idle current consumption is ~0.055 mA at VCC
=
2.0V and F = 1MHz. The total current consumption in idle mode with TIMER1, ADC, and SPI
enabled, gives:
ICCtotal ≈ 0.045 mA ⋅ (1 + 0.145 + 0.221 + 0.157) ≈ 0.069 mA
404
8161D–AVR–10/09
ATMEL [ ATMEL ]
