ATmega16HVB datasheet(130/273 Pages) ATMEL

130 / 273 page

130

8042A–AVR–07/09

ATmega16HVB/32HVB

22.3

Operation

The Charger Detect module is supplied directly from the VFET pin. When operating, the Charger

Detect will monitor the voltage of the BATT pin and detect whether a charger is present or not.

When the voltage on the BATT pin is above the Charger Detect Threshold level V

POT (”Electrical

Characteristics” on page 228) the CHARGER_PRESENT signal will be high. This signal is edge

detected to generate interrupt when a charger is connected or disconnected.

The Charger Detect module will operate as long as the Discharge FET is disabled and is able to

detect a charger in all sleep modes including Power-off.

22.3.1

Device operating state

The Charger Detect module controls the operating state of the ATmega16HVB/32HVB by

enabling/disabling the Voltage Regulator, which supplies the rest of the internal logic on the

chip.

If the chip is in Power-off state the Charger Detect will keep the Voltage Regulator disabled

allowing only the Charger Detect module itself to operate. To be able to start from a Power-off

state a charge voltage above V

POT has to be applied at the BATT pin. When a charger is con-

nected the Charger Detect module will automatically start the Voltage Regulator. When the

VREG voltage rises, a Power-on Reset (POR) is given and the chip enters normal operating

mode after a reset delay corresponding to T

TOUT. For details on POR, see ”Power-on Reset and

Charger Connect” on page 43.

When the ATmega16HVB/32HVB is running in normal operation mode software or hardware

could take the chip into Power-off state. For details on entering power-off by software, see

”Power-off Mode” on page 38. To protect the device against software malfunctions the

ATmega16HVB/32HVB has a Black-out Detector (BLOD). When a Black-out condition occurs

the Charger Detect will take the chip automatically into Power-off. For details on Black-out

Detection, see ”Voltage Regulator” on page 132.

Note that after a software power-off the BATT pin voltage has to fall below the Charger Detect

threshold limit, VPOT, before the chip is able to re-enable the Voltage Regulator and start-up the

device.

22.3.2

Interrupt logic

When the ATmega16HVB/32HVB is running in normal operation mode, the Charger Detect is

capable of giving an interrupt to the CPU if a charger is connected/disconnected or both. Inter-

rupt is enabled/disabled by writing to the CHGDIE bit in the ”CHGDCSR - Charger Detect

Control and Status Register” on page 131.

Interrupt is given when a charger is connected, disconnected or both depending on interrupt

sense control settings. Selecting the correct interrupt sensing is done by writing to the CHGDISC

bits in the ”CHGDCSR - Charger Detect Control and Status Register” on page 131.

Charger Detect interrupt works asynchronous and will wake the CPU from any sleep mode.

The Charger Detect is automatically disabled/enabled when changing the state of the Discharge

FET, and any interrupt that occurs when enabling or disabling the Discharge FET has to be

carefully interpreted.

•

When enabling the Discharge-FET the Charger Detect module is automatically disabled.

When disabling the charger detect module a charger appear to be disconnected even if a

charger is present.

ATmega16HVB 数据表(PDF) 130 Page - ATMEL Corporation

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