ATmega88PA Automotive Atmel Corporation, ATmega88PA Automotive Datasheet - Page 43

• Manufacturer Part Number: ATmega88PA Automotive
• Manufacturer: Atmel Corporation

10.10.4
10.10.5
10.10.6
10.10.7
9223B–AVR–09/11
Internal Voltage Reference
Watchdog Timer
Port Pins
On-chip Debug System
The Internal Voltage Reference will be enabled when needed by the Brown-out Detection, the
Analog Comparator or the ADC. If these modules are disabled as described in the sections
above, the internal voltage reference will be disabled and it will not be consuming power.
When turned on again, the user must allow the reference to start up before the output is used.
If the reference is kept on in sleep mode, the output can be used immediately. Refer to
nal Voltage Reference” on page 51
If the Watchdog Timer is not needed in the application, the module should be turned off. If the
Watchdog Timer is enabled, it will be enabled in all sleep modes and hence always consume
power. In the deeper sleep modes, this will contribute significantly to the total current con-
sumption. Refer to
Timer.
When entering a sleep mode, all port pins should be configured to use minimum power. The
most important is then to ensure that no pins drive resistive loads. In sleep modes where both
the I/O clock (clk
be disabled. This ensures that no power is consumed by the input logic when not needed. In
some cases, the input logic is needed for detecting wake-up conditions, and it will then be
enabled. Refer to the section
which pins are enabled. If the input buffer is enabled and the input signal is left floating or have
an analog signal level close to V
For analog input pins, the digital input buffer should be disabled at all times. An analog signal
level close to V
input buffers can be disabled by writing to the Digital Input Disable Registers (DIDR1 and
DIDR0). Refer to
Input Disable Register 0” on page 266
If the On-chip debug system is enabled by the DWEN Fuse and the chip enters sleep mode,
the main clock source is enabled and hence always consumes power. In the deeper sleep
modes, this will contribute significantly to the total current consumption.
Atmel ATmega48PA/88PA/168PA [Preliminary]
CC
I/O
“DIDR1 – Digital Input Disable Register 1” on page 247
/2 on an input pin can cause significant current even in active mode. Digital
) and the ADC clock (clk
“Watchdog Timer” on page 51
“Digital Input Enable and Sleep Modes” on page 77
CC
/2, the input buffer will use excessive power.
for details on the start-up time.
for details.
ADC
) are stopped, the input buffers of the device will
for details on how to configure the Watchdog
and
“DIDR0 – Digital
for details on
“Inter-
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