ATmega406 Atmel Corporation, ATmega406 Datasheet - Page 107

• 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

18.2
2548E–AVR–07/06
Operation
When enabled, the CC-ADC continuously measures the voltage over the external sense resistor
R
The Instantaneous Current conversion time is fixed to 3.9 ms (typical value) allowing the output
value to closely follow the input. After each Instantaneous Current conversion an interrupt is
generate if the interrupt is enabled. Data from conversion will be updated in the Instantaneous
Current registers - CADICL and CADICH simultaneously as the interrupt is given. To avoid los-
ing conversion data, both the low and high byte must be read within a 3,9 ms timing window after
the corresponding interrupt is given. When the low byte register is read, updating of the Instanta-
neous Current registers and interrupts will be stopped until the high byte is read.
shows an Instantaneous Current conversion diagram, where DATA4 will be lost because DATA3
reading is not completed within the limited period.
Figure 18-2. Instantaneous Current Conversion
The Accumulate Current output is a high-resolution, high accuracy output with programmable
conversion time selected by the CADAS bits in CADCSRA. The converted value is an accurate
measurement of the average current flow during one conversion period. The CC-ADC generates
an interrupt each time a new Accumulate Current conversion has finished if the interrupt is
enabled. Data from conversion will be updated in the Accumulation Current registers - CADAC0,
CADAC1, CADAC2 and CADAC3 simultaneously as the interrupt is given. To avoid losing con-
version data, all bytes must be read within the selected conversion period. When the lower byte
registers are read, updating of the Accumulation Current registers and interrupts will be stopped
until the highest byte is read.
sion example, where DATA4 will be lost because DATA3 reading is not completed within the
limited period.
Instantaneous Interrupt
SENSE
Instantaneous Data
Read high byte
Read low byte
.
Enable
Setting of Digital Filters
~12 ms settling
Figure 18-3 on page 108
3.9 ms
DATA1
shows an Accumulation Current conver-
3.9 ms
DATA2
DATA 3
7.8 ms
ATmega406
DATA5
Figure 18-2
107