AT90USB1286 Atmel Corporation, AT90USB1286 Datasheet - Page 46

• Manufacturer Part Number: AT90USB1286
• Manufacturer: Atmel Corporation

Specifications of AT90USB1286

• Flash (kbytes): 128 Kbytes
• Pin Count: 64
• Max. Operating Frequency: 16 MHz
• Cpu: 8-bit AVR
• # Of Touch Channels: 16
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 48
• Ext Interrupts: 16
• Usb Transceiver: 1
• Usb Speed: Full Speed
• Usb Interface: Device
• Spi: 2
• Twi (i2c): 1
• Uart: 1
• 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): 8
• Eeprom (bytes): 4096
• Self Program Memory: YES
• Dram Memory: No
• Nand Interface: No
• Picopower: No
• Temp. Range (deg C): -40 to 85
• I/o Supply Class: 2.7 to 5.5
• Operating Voltage (vcc): 2.7 to 5.5
• Fpu: No
• Mpu / Mmu: no / no
• Timers: 4
• Output Compare Channels: 10
• Input Capture Channels: 1
• Pwm Channels: 9
• 32khz Rtc: Yes
• Calibrated Rc Oscillator: Yes

6.7
6.8
46
Clock Output Buffer
Timer/Counter Oscillator
AT90USB64/128
Figure 6-3.
When this clock source is selected, start-up times are determined by the SUT Fuses as shown in
Table
Table 6-9.
When applying an external clock, it is required to avoid sudden changes in the applied clock fre-
quency to ensure stable operation of the MCU. A variation in frequency of more than 2% from
one clock cycle to the next can lead to unpredictable behavior. If changes of more than 2% is
required, ensure that the MCU is kept in Reset during the changes.
Note that the System Clock Prescaler can be used to implement run-time changes of the internal
clock frequency while still ensuring stable operation. Refer to
47
The device can output the system clock on the CLKO pin. To enable the output, the CKOUT
Fuse has to be programmed. This mode is suitable when the chip clock is used to drive other cir-
cuits on the system. The clock also will be output during reset, and the normal operation of I/O
pin will be overridden when the fuse is programmed. Any clock source, including the internal RC
Oscillator, can be selected when the clock is output on CLKO. If the System Clock Prescaler is
used, it is the divided system clock that is output.
The device can operate its Timer/Counter2 from an external 32.768 kHz watch crystal or a exter-
nal clock source. See
Applying an external clock source to TOSC1 requires EXCLK in the ASSR Register written to
logic one. See
tion on selecting external clock as input instead of a 32 kHz crystal.
BOD enabled
Fast rising power
Slowly rising power
for details.
Power Conditions
6-9.
External Clock Drive Configuration
Start-up Times for the External Clock Selection
“Asynchronous operation of the Timer/Counter” on page 165
Figure 6-2 on page 42
EXTERNAL
SIGNAL
CLOCK
Start-up Time from Power-
down and Power-save
NC
Reserved
6 CK
6 CK
6 CK
for crystal connection.
XTAL2
XTAL1
GND
Additional Delay from
“System Clock Prescaler” on page
Reset (V
14CK + 4.1 ms
14CK + 65 ms
14CK
CC
= 5.0V)
for further descrip-
7593K–AVR–11/09
SUT1..0
00
01
10
11