ATmega1284P datasheet(340/380 Pages) ATMEL

340 / 380 page

340

8059D–AVR–11/09

ATmega1284P

27.3

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 Reduction Register. See ”PRR0 – Power Reduction Register 0” on

page 46 for details.

It is possible to calculate the typical current consumption based on the numbers from Table 27-2

on page 340 for other V

CC and frequency settings than listed in Table 27-1 on page 340.

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 27-2 on page 340, third column, we see that we need

to add 8.0% for the TIMER1, 19.8% for the ADC, and 13.2% for the SPI module. Reading from

Figure 27-7 on page 337

, we find that the idle current consumption is ~0.075 mA at V

CC = 2.0V

and F = 1MHz. The total current consumption in idle mode with TIMER1, ADC, and SPI enabled,

gives:

Table 27-1.

Additional Current Consumption for the different I/O modules (absolute values)

PRR bit

Typical numbers in

VCC = 2V, F = 1 MHz

VCC = 3V, F = 4 MHz

VCC = 5V, F = 8 MHz

PRUSART1

3.0 µA

19.2 µA

87.7 µA

PRUSART0

2.9 µA

19.2 µA

88.5 µA

PRTWI

7.5 µA

49.3 µA

230.3 µA

PRTIM3

4.0 µA

24.7 µA

105.5 µA

PRTIM2

6.0 µA

39.7 µA

176.3 µA

PRTIM1

4.2 µA

26.4 µA

113.7 µA

PRTIM0

1.7 µA

11.6 µA

54.3 µA

PRADC

13.5 µA

54.7 µA

273 µA

PRSPI

5.7 µA

40.6 µA

212.2 µA

Table 27-2.

Additional Current Consumption (percentage) in Active and Idle mode

PRR bit

Additional Current consumption

compared to Active with external

clock (see Figure 27-1 on page

334 and Figure 27-2 on page 335)

Additional Current consumption

compared to Idle with external

clock (see Figure 27-6 on page

337 and Figure 27-7 on page 337)

PRUSART1

0.9%

6.0%

PRUSART0

0.9%

6.0%

PRTWI

2.3%

15.4%

PRTIM3

1.1%

7.5%

PRTIM2

1.8%

12.1%

PRTIM1

1.2%

8.0%

PRTIM0

0.5%

3.6%

PRTADC

3.0%

19.8%

PRSPI

2.0%

13.2%

ATmega1284P Datasheet(PDF) 340 Page - ATMEL Corporation

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