ATmega406 Atmel Corporation, ATmega406 Datasheet - Page 116

• 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

20. Voltage ADC – 10-channel General Purpose 12-bit Sigma-Delta ADC
20.1
116
Features
ATmega406
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The ATmega406 features a 12-bit Sigma-Delta ADC. Automatic offset cancellation technique
reduces the input offset voltage to less than 0.5 mV.
The Voltage ADC (V-ADC) is connected to ten different sources through the Input Multiplexer.
There are four differential channels for Cell Voltage measurements. These channels are scaled
0.2x to comply with the Full Scale range of the V-ADC. In addition there are six single ended
channels referenced to SGND. One channel is for measuring the internal temperature sensor
VPTAT and five channels for measuring the ADC input pins at Port A. ADC3:0 are not scaled,
meaning that full-scale reading corresponds to 1.1 V. ADC4 is scaled by 0.2x, meaning that full-
scale reading corresponds to 5.5 V. The ADC4 input can be used to measure the voltage at the
PA4 pin when this pin is used to supply an external thermistor, see
To obtain a total absolute accuracy better than ± 0.25% for the cell voltage measurements, cali-
bration registers for the individual cell voltage gain in the analog front-end is provided. A factory
calibration value is stored in the signature row, see
from Software” on page
corresponding calibration value by software to correct for gain error in the analog front-end.
The PRVADC bit in
enable V-ADC module.
12-bit Resolution
±1 LSB Accuracy
519µs Conversion Time
Four Differential Input Channels for Cell Voltage Measurements
Six Single Ended Input Channels
0 to 0.9 x VREF Input Voltage Range
0.2x Pre-scaling of Cell Voltages and VREG
Interrupt on V-ADC Conversion Complete
”PRR0 – Power Reduction Register 0” on page 36
189. The V-ADC conversion of a cell voltage must be scaled with the
Section 27.7.10 ”Reading the Signature Row
Figure 29-1 on page
must be written to zero to
2548E–AVR–07/06
223.