AT90USB647-MU Atmel, AT90USB647-MU Datasheet - Page 42

• Manufacturer Part Number: AT90USB647-MU
• Description: MCU, 8BIT, 64K FLASH, USB, 64QFN
• Manufacturer: Atmel

Specifications of AT90USB647-MU

• Controller Family/series: AT90
• No. Of I/o's: 48
• Eeprom Memory Size: 2KB
• Ram Memory Size: 4KB
• Cpu Speed: 16MHz
• No. Of: RoHS Compliant
• Core Size: 8bit
• Program Memory Size: 64KB
• Oscillator Type: External, Internal
• Package: 64QFN EP
• Device Core: AVR
• Family Name: AT90
• Maximum Speed: 20 MHz
• Ram Size: 4 KB
• Operating Supply Voltage: 3.3|5 V
• Data Bus Width: 8 Bit
• Program Memory Type: Flash
• Number Of Programmable I/os: 48
• Interface Type: SPI/TWI/USART/USB
• On-chip Adc: 8-chx10-bit
• Operating Temperature: -40 to 85 °C
• Number Of Timers: 4
• Lead Free Status / Rohs Status: Details

42
AT90USB64/128
Figure 6-2.
The Low Power Oscillator can operate in three different modes, each optimized for a specific fre-
quency range. The operating mode is selected by the fuses CKSEL3..1 as shown in
Table 6-3.
Notes:
The CKSEL0 Fuse together with the SUT1..0 Fuses select the start-up times as shown in
6-4.
Table 6-4.
Oscillator Source /
Power Conditions
Ceramic resonator, fast
rising power
Ceramic resonator, slowly
rising power
Ceramic resonator, BOD
enabled
Ceramic resonator, fast
rising power
Ceramic resonator, slowly
rising power
Frequency Range
1. The frequency ranges are preliminary values. Actual values are TBD.
2. This option should not be used with crystals, only with ceramic resonators.
3. If 8 MHz frequency exceeds the specification of the device (depends on V
Fuse can be programmed in order to divide the internal frequency by 8. It must be ensured
that the resulting divided clock meets the frequency specification of the device.
8.0 - 16.0
0.4 - 0.9
0.9 - 3.0
3.0 - 8.0
Crystal Oscillator Connections
Low Power Crystal Oscillator Operating Modes
Start-up Times for the Low Power Crystal Oscillator Clock Selection
(1)
(MHz)
Start-up Time from
Power-down and
Power-save
258 CK
258 CK
1K CK
1K CK
1K CK
C2
C1
CKSEL3..1
100
101
110
111
(2)
Additional Delay
14CK + 4.1 ms
14CK + 4.1 ms
Recommended Range for Capacitors C1
14CK + 65 ms
14CK + 65 ms
(V
from Reset
XTAL2
XTAL1
GND
CC
14CK
= 5.0V)
(3)
(2)
(1)
(2)
(1)
(2)
and C2 (pF)
12 - 22
12 - 22
12 - 22
–
CKSEL0
CC
0
0
0
0
1
), the CKDIV8
7593K–AVR–11/09
Table
SUT1..0
00
01
10
11
00
Table
6-3.