ATmega406 Atmel Corporation, ATmega406 Datasheet - Page 25

• Manufacturer Part Number: ATmega406
• Manufacturer: Atmel Corporation

Specifications of ATmega406

• Flash (kbytes): 40 Kbytes
• Pin Count: 48
• Max. Operating Frequency: 1 MHz
• Cpu: 8-bit AVR
• # Of Touch Channels: 8
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 18
• Ext Interrupts: 4
• Usb Speed: No
• Usb Interface: No
• Twi (i2c): 1
• Graphic Lcd: No
• Video Decoder: No
• Camera Interface: No
• Adc Channels: 11
• Adc Resolution (bits): 12
• Adc Speed (ksps): 1.9
• Resistive Touch Screen: No
• Temp. Sensor: Yes
• Crypto Engine: No
• Sram (kbytes): 2
• Eeprom (bytes): 512
• Self Program Memory: YES
• Dram Memory: No
• Nand Interface: No
• Picopower: No
• Temp. Range (deg C): -30 to 85
• I/o Supply Class: 4.0 to 25
• Operating Voltage (vcc): 4.0 to 25
• Fpu: No
• Mpu / Mmu: no / no
• Timers: 2
• Output Compare Channels: 3
• Pwm Channels: 2
• 32khz Rtc: Yes
• Calibrated Rc Oscillator: Yes

2548ES–AVR–07/06
4. Voltage Regulator Start-up sequence
5.
6. EEPROM read from application code does not work in Lock Bit Mode 3
When powering up ATmega406 some precautions are necessary to ensure proper start-up
of the Voltage Regulator.
Problem Fix/Workaround
The three steps below are needed to ensure proper start-up of the voltage regulator.
a. Do NOT connect a capacitor larger than 100 nF on the VFET pin. This is to ensure
b. During assembly, always connect Cell1 first, then Cell2 and so on until the top cell is
c. After all cells have been assembled as described in step 2, a charger source must be
If the Voltage Regulator started up in Power-off during assembly of the cells, the chip will ini-
tialize when the charger source makes the voltage at the BATT pin exceed 7 - 8 Volts.
If the Voltage Regulator did not start up properly, the charger source has one additional
requirement to ensure proper start up and initialization. In this case the charger source must
ensure that the voltage at the VFET pin increases quickly at least 3 Volts above the voltage
at the PVT pin, and that the voltage at the BATT pin exceeds 7 - 8 Volts. This will start up
and initialize the chip directly.
The reference voltage at the V
a. Charger Over-current and/or Discharge Over-current Protection active but Short-cir-
b. Short-circuit Protection active. Short-circuit measurements are activated when SCD
c. V-ADC conversion of the internal VTEMP voltage. This will increase V
Problem Fix/Work around
To ensure the highest accuracy, set the Bandgap Calibration Register (BGCC) to get 1.100
V at V
charge FET is enabled.
When the Memory Lock Bits LB2 and LB1 are programmed to mode 3, EEPROM read does
not work from the application code.
Problem Fix/Work around
Do not set Lock Bit Protection Mode 3 when the application code needs to read from
EEPROM.
V
REF
fast rise time on the VFET pin when a supply voltage is connected.
connected to PVT. If the cell voltages are about 2 volts or larger, the Voltage Regula-
tor will normally start up properly in Power-off mode (VREG appr. 2.8 volts).
connected at the BATT+ terminal to initialize the chip, see
Reset and Charger Connect” on page 38
cuit inactive. This will increase V
condition were all Current Protections are disabled.
in BPCR is zero (default) and DFE in FET Control and Status Register (FCSR) is set.
This will increase V
circuit measurements inactive.
with typical 15 mV compared to a condition with short-circuit measurements inactive.
influenced by MCU state
REF
after the chip is configured with the actual Battery Protection settings and the Dis-
REF
voltage with typical 8 mV compared to a condition with short-
REF
pin depends on the following conditions of the device:
REF
voltage with typical 1 mV compared to a
in the datasheet.
Section 8.3 ”Power-on
ATmega406
REF
voltage
25