ATMEGA644A-PU Atmel, ATMEGA644A-PU Datasheet - Page 478

• Manufacturer Part Number: ATMEGA644A-PU
• Description: IC MCU AVR 64K FLASH 40PDIP
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA644A-PU

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 20MHz
• Connectivity: I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 32
• Program Memory Size: 64KB (32K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 2K x 8
• Ram Size: 4K x 8
• Voltage - Supply (vcc/vdd): 1.8 V ~ 5.5 V
• Data Converters: A/D 8x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 40-DIP (0.600", 15.24mm)
• Processor Series: ATmega
• Core: AVR
• Data Bus Width: 8 bit
• Data Ram Size: 4 KB
• Interface Type: JTAG, TWI, SPI, USART
• Maximum Clock Frequency: 20 MHz
• Number Of Programmable I/os: 32
• Number Of Timers: 3
• Operating Supply Voltage: 3.3 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: Through Hole
• Minimum Operating Temperature: - 40 C
• Operating Temperature Range: - 40 C to + 85 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

28.6.3
Example
8272A–AVR–01/10
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
page 49
Table 28-11. Additional Current Consumption for the different I/O modules (absolute values)
Table 28-12. Additional Current Consumption (percentage) in Active and Idle mode
It is possible to calculate the typical current consumption based on the numbers from
12 on page 478
Calculate the expected current consumption in idle mode with TIMER1, ADC, and SPI enabled
at V
to add 9.1% for the TIMER1, 17.9% for the ADC, and 12.4% for the SPI module. Reading from
Figure 28-251 on page
2.0V and F = 1MHz. The total current consumption in idle mode with TIMER1, ADC, and SPI
enabled, gives:
164A/164PA/324A/324PA/644A/644PA/1284/1284P
PRR bit
PRUSART1
PRUSART0
PRTWI
PRTIM2
PRTIM1
PRTIM0
PRADC
PRSPI
PRR bit
PRUSART1
PRUSART0
PRTWI
PRTIM2
PRTIM1
PRTIM0
PRADC
PRSPI
CC
= 2.0V and F = 1MHz. From
for details.
for other V
Typical numbers in
Additional Current consumption
compared to Active with external
clock (see
473
473)
V
CC
I
CC
and
= 2V, F = 1 MHz
total
475, we find that the idle current consumption is ~0.078 mA at V
16.2 µA
5.9 µA
6.7 µA
9.5 µA
6.6 µA
3.1 µA
9.3 µA
12 µA
Figure 28-247 on page
CC
≈
Figure 28-246 on page
0.070 mA (1+ 0.091 + 0.179 + 0.124)
and frequency settings than listed in
3.65%
1.6%
1.8%
2.6%
3.3%
1.9%
0.9%
2.5%
Table 28-12 on page
⋅
V
CC
= 3V, F = 4 MHz
37.3 µA
58.9 µA
74.3 µA
41.4 µA
19.5 µA
75.4 µA
56.6 µA
40 µA
Additional Current consumption
compared to Idle with external
clock (see
475
476)
”PRR – Power Reduction Register” on
478, third column, we see that we need
and
Figure 28-252 on page
≈
Figure 28-251 on page
0.091 mA
V
Table 28-11 on page
12.9%
16.3%
17.9%
12.4%
8.1%
8.8%
9.1%
4.3%
CC
= 5V, F = 8 MHz
157.1 µA
239.5 µA
297.6 µA
170.3 µA
301.4 µA
226.3 µA
78.6 µA
149 µA
Table 28-
478.
CC
478
=