ata6616 ATMEL Corporation, ata6616 Datasheet - Page 67

• Manufacturer Part Number: ata6616
• Description: Microcontroller With Lin Transceiver, 5v Regulator And Watchdog
• Manufacturer: ATMEL Corporation

4.6.2
4.6.3
4.6.4
9132A–AUTO–10/08
DRAFT
BOD Disable
Idle Mode
ADC Noise Reduction Mode
When the Brown-out Detector (BOD) is enabled by BODLEVEL fuses,
the BOD is actively monitoring the power supply voltage during a sleep period. To save power, it
is possible to disable the BOD by software for some of the sleep modes, see
sleep mode power consumption will then be at the same level as when BOD is globally disabled
by fuses. If BOD is disabled in software, the BOD function is turned off immediately after enter-
ing the sleep mode. Upon wake-up from sleep, BOD is automatically enabled again. This
ensures safe operation in case the Vcc level has dropped during the sleep period.
When the BOD has been disabled, the wake-up time from sleep mode will be approximately 60
µs to ensure that the BOD is working correctly before the MCU continues executing code.
BOD disable is controlled by BODS bit (BOD Sleep) in the control register MCUCR, see
“MCUCR – MCU Control Register” on page
sleep modes, while a zero in this bit keeps BOD active. Default setting keeps BOD active, i.e.
BODS is cleared to zero.
Writing to the BODS bit is controlled by a timed sequence and an enable bit, see
MCU Control Register” on page
When the SM1..0 bits are written to 00, the SLEEP instruction makes the MCU enter Idle mode,
stopping the CPU but allowing the SPI, Analog Comparator, ADC, USI start condition, Asynchro-
nous Timer/Counter, Watchdog, and the interrupt system to continue operating. This sleep
mode basically halts clk
Idle mode enables the MCU to wake up from external triggered interrupts as well as internal
ones like the SPI interrupts. If wake-up from the Analog Comparator interrupt is not required, the
Analog Comparator can be powered down by setting the ACD bit in the Analog Comparator
Control and Status Register – ACSR. This will reduce power consumption in Idle mode. If the
ADC is enabled, a conversion starts automatically when this mode is entered.
When the SM1..0 bits are written to 01, the SLEEP instruction makes the MCU enter ADC Noise
Reduction mode, stopping the CPU but allowing the ADC, the external interrupts, the USI start
condition, the asynchronous Timer/Counter and the Watchdog to continue operating (if
enabled). This sleep mode basically halts clk
clocks to run.
This improves the noise environment for the ADC, enabling higher resolution measurements. If
the ADC is enabled, a conversion starts automatically when this mode is entered. Apart from the
ADC Conversion Complete interrupt, only an External Reset, a Watchdog System Reset, a
Watchdog Interrupt, a Brown-out Reset, a USI start condition interrupt, an asynchronous
Timer/Counter interrupt, an SPM/EEPROM ready interrupt, an external level interrupt on INT0 or
INT1 or a pin change interrupt can wake up the MCU from ADC Noise Reduction mode.
CPU
and clk
71.
ATA6616/ATA6617 [Preliminary]
FLASH
, while allowing the other clocks to run.
71. Setting it to one turns off the BOD in relevant
I/O
, clk
CPU
, and clk
FLASH
, while allowing the other
Table 4-68 on page
Table
“MCUCR –
4-15. The
251,
67