Datasheet

413
ATmega169A/PA/329A/PA/649A/P/3290A/PA/6490A/P [DATASHEET]
8284E–AVR–02/2013
31.3.3 Atmel ATmega329A: 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 Reduc-
tion Register. See ”PRR – Power Reduction Register” on page 45 for details.
It is possible to calculate the typical current consumption based on the numbers from Table 31-2 on page 349 for
other V
CC
and frequency settings than listed in Table 31-1 on page 349.
31.3.3.1 Example 1
Calculate the expected current consumption in idle mode with USART0, TIMER1, and SPI enabled at V
CC
= 3.0V
and F = 1MHz. From Table 31-2 on page 349, second column, we see that we need to add 13.1% for the USART0,
13.0% for the SPI, and 13.2% for the TIMER1 module. Reading from Figure 31-6 on page 347, we find that the idle
current consumption is ~0.09 mA at V
CC
= 3.0V and F = 1MHz. The total current consumption in idle mode with
USART0, TIMER1, and SPI enabled, gives:
Table 31-5. ATmega329A: 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
PRADC 7µA 44µA 195µA
PRUSART0 6.9µA 43.5µA 210µA
PRSPI 6.6µA 47µA 205µA
PRTIM1 7µA 47µA 206µA
PRLCD 7.3µA 48µA 215µA
Table 31-6. ATmega329A: Additional current consumption (percentage) in Active and Idle mode.
PRR bit
Additional current consumption
compared to Active with external clock
(see Figure 31-1 on page 344 and
Figure 31-2 on page 345)
Additional current consumption
compared to Idle with external clock
(see Figure 31-6 on page 347 and
Figure 31-7 on page 347)
PRADC 3.2% 12.7%
PRUSART0 3.4% 13.1%
PRSPI 3.3% 13.0%
PRTIM1 3.4% 13.2%
PRLCD 3.5% 13.7%
ICCtotal 0.09mA 1 0.131 0.13 0.132+++ 0.13mA