ATmega3290A Atmel Corporation, ATmega3290A Datasheet - Page 35

• Manufacturer Part Number: ATmega3290A
• Manufacturer: Atmel Corporation

Specifications of ATmega3290A

• Flash (kbytes): 32 Kbytes
• Pin Count: 100
• Max. Operating Frequency: 20 MHz
• Cpu: 8-bit AVR
• # Of Touch Channels: 16
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 69
• Ext Interrupts: 32
• Usb Speed: No
• Usb Interface: No
• Spi: 2
• Twi (i2c): 1
• Uart: 1
• Segment Lcd: 160
• Graphic Lcd: No
• Video Decoder: No
• Camera Interface: No
• Adc Channels: 8
• Adc Resolution (bits): 10
• Adc Speed (ksps): 15
• Analog Comparators: 1
• Resistive Touch Screen: No
• Temp. Sensor: No
• Crypto Engine: No
• Sram (kbytes): 2
• Eeprom (bytes): 1024
• Self Program Memory: YES
• Dram Memory: No
• Nand Interface: No
• Picopower: No
• Temp. Range (deg C): -40 to 85
• I/o Supply Class: 1.8 to 5.5
• Operating Voltage (vcc): 1.8 to 5.5
• Fpu: No
• Mpu / Mmu: no / no
• Timers: 3
• Output Compare Channels: 4
• Input Capture Channels: 1
• Pwm Channels: 4
• 32khz Rtc: Yes
• Calibrated Rc Oscillator: Yes

9.7
8284D–AVR–6/11
External Clock
ATmega169A/PA/329A/PA/3290A/PA/649A/P/6490A/P
The Low-frequency Crystal Oscillator provides an internal load capacitance,
each TOSC pin.
Table 9-9.
The capacitance (Ce + Ci) needed at each TOSC pin can be calculated by using:
where
Ce - is optional external capacitors as described in
Ci - is the pin capacitance in
CL - is the load capacitance for a 32.768kHz crystal specified by the crystal vendor.
C
Crystals specifying load capacitance (CL) higher than the ones given in the
external capacitors applied as described in
To find suitable load capacitance for a 32.768kHz crystal, please consult the crystal datasheet.
The Low-frequency Crystal Oscillator must be selected by setting the CKSEL Fuses to “0110” or
“0111” as shown in
shown in
Table 9-10.
Table 9-11.
Note:
To drive the device from an external clock source, XTAL1 should be driven as shown in
9-3. To run the device on an external clock, the CKSEL Fuses must be programmed to “0000”.
ATmega169A/169PA/329A/329PA/3290A
S
CKSEL3...
SUT1..0
- is the total stray capacitance for one TOSC pin.
0110
/3290PA/649A/649P/6490A/6490P
0111
00
01
10
11
0
(1)
1. This option should only be used if frequency stability at start-up is not important for the
Table
application
Capacitance for Low-frequency Oscillator.
Start-up Times for the Low-frequency Crystal Oscillator Clock Selection
Start-up Times for the Low-frequency Crystal Oscillator Clock Selection
Additional Delay from Reset (V
9-10.
Device
Table 9-11 on page
Power-down and Power-save
Start-up Time from
4 CK + 4.1ms
4 CK + 65ms
Table 9-10
32K CK
1K CK
4 CK
Ce
35. Start-up times are determined by the SUT Fuses as
+
32kHz Osc. Type
Ci
System Osc.
Figure 9-2 on page
Timer Osc.
CC
=
= 5.0V)
2 CL
⋅
Reserved
Figure 9-2 on page 33
–
C
s
Recommended Usage
Fast rising power or BOD enabled
Slowly rising power
Stable frequency at start-up
Recommended Usage
Stable frequency at start-up
Cap(Xtal1/Tosc1)
33.
16pF
16pF
Table
Cap(Xtal2/Tosc2)
seeTable 9-9
9-9, require
6pF
6pF
Figure
35
at