413
8271D–AVR–05/11
ATmega48A/PA/88A/PA/168A/PA/328/P
30.4.3
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 43
for
details.
It is possible to calculate the typical current consumption based on the numbers from
for other V
CC
and frequency settings than listed in
30.4.3.1
Example
Calculate the expected current consumption in idle mode with TIMER1, ADC, and SPI enabled
at V
CC
= 2.0V and F = 1MHz. From
, 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
, 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 30-7.
ATmega88PA: 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
3.0uA
21.3uA
97.9uA
PRTWI
6.1uA
45.4uA
219.0uA
PRTIM2
5.2uA
35.2uA
149.5uA
PRTIM1
3.8uA
25.6uA
110.0uA
PRTIM0
1.5uA
9.8uA
39.6uA
PRSPI
5.2uA
40.0uA
199.6uA
PRADC
6.3uA
48.7uA
247.0uA
Table 30-8.
ATmega88PA: Additional Current Consumption (percentage) in Active and Idle
mode
PRR bit
Additional Current consumption
compared to Active with external
clock (see
and
)
Additional Current consumption
compared to Idle with external
clock (see
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%
I
CC
total
0.027 mA (1 + 0.136 + 0.263 + 0.215)
⋅
0.043 mA
≈
≈