ATmega406 Atmel Corporation, ATmega406 Datasheet - Page 22

• 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

8.3
22
Rev. D
ATmega406
Figure 8-4.
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1. Voltage-ADC Failing at Low Temperatures
1. Voltage-ADC Common Mode Offset
Voltage ADC not functional below 0
Voltage-ADC Common Mode Offset
Voltage Reference Spike
Voltage Regulator Start-up sequence
V
EEPROM read from application code does not work in Lock Bit Mode 3
REF
VADMUX3:0
If the CC-ADC is doing current accumulation while the V-ADC is doing temperature mea-
surement, both the Instantaneous and the Accumulated conversion results will be affected.
The spike on VREF will be visible on 1 Accumulated Current (CADAC3…0) and 2 Instanta-
neous Current (CADIC1…0) conversion results.
Voltage ADC not functional below 0°C. The voltage ADC has a very large error below 0°C,
and can not be used
Problem Fix/Workaround
The cell conversion will have an Offset-error depending on the Common Mode (CM) level.
This means that the error of a cell is depending on the voltage of the lower cells. The CM
Offset is calibrated away in Atmel production when the cells are balanced. When the cells
get un-balanced the CM depending offset will reappear:
influenced by MCU state
VADSC
1.1 V
Voltage
XXX
Voltage Reference Spike
V~50mV
°C
(10 VTEMP conversion in a row)
VTEMP
t ~< 5ms
VREF
time
2548ES–AVR–07/06