AT90USB1287-AU Atmel, AT90USB1287-AU Datasheet - Page 45

• Manufacturer Part Number: AT90USB1287-AU
• Description: IC AVR MCU 128K 64TQFP
• Manufacturer: Atmel
• Series: AVR® 90USBr

Specifications of AT90USB1287-AU

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 16MHz
• Connectivity: EBI/EMI, I²C, SPI, UART/USART, USB, USB OTG
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 48
• Program Memory Size: 128KB (128K x 8)
• Program Memory Type: FLASH
• Eeprom Size: 4K x 8
• Ram Size: 8K x 8
• Voltage - Supply (vcc/vdd): 2.7 V ~ 5.5 V
• Data Converters: A/D 8x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 64-TQFP, 64-VQFP
• Processor Series: AT90USBx
• Core: AVR8
• Data Bus Width: 8 bit
• Data Ram Size: 8 KB
• Interface Type: 2-Wire/SPI/USART
• Maximum Clock Frequency: 20 MHz
• Number Of Programmable I/os: 48
• Number Of Timers: 4
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• 3rd Party Development Tools: EWAVR, EWAVR-BL
• Development Tools By Supplier: ATAVRDRAGON, ATSTK500, ATSTK600, ATSTK525, ATAVRISP2, ATAVRONEKIT, AT90USBKEY, ATEVK525, ATAVRQTOUCHX
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 8-ch x 10-bit
• Controller Family/series: AVR USB
• No. Of I/o's: 48
• Eeprom Memory Size: 4KB
• Ram Memory Size: 8KB
• Cpu Speed: 20MHz
• Rohs Compliant: Yes
• For Use With: ATSTK600-TQFP64 - STK600 SOCKET/ADAPTER 64-TQFP770-1007 - ISP 4PORT ATMEL AVR MCU SPI/JTAGATSTK525 - KIT STARTER FOR AT90USBAT90USBKEY2 - KIT DEMO FOR AT90USB
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: AT90USB1287-16AU; AT90USB1287-16AU

6.5.1
6.6
7593K–AVR–11/09
External Clock
Oscillator Calibration Register – OSCCAL
Table 6-8.
Note:
• Bits 7..0 – CAL7..0: Oscillator Calibration Value
The Oscillator Calibration Register is used to trim the Calibrated Internal RC Oscillator to
remove process variations from the oscillator frequency. The factory-calibrated value is automat-
ically written to this register during chip reset, giving an oscillator frequency of 8.0 MHz at 25°C.
The application software can write this register to change the oscillator frequency. The oscillator
can be calibrated to any frequency in the range 7.3 - 8.1 MHz within ±10% accuracy. Calibration
outside that range is not guaranteed.
Note that this oscillator is used to time EEPROM and Flash write accesses, and these write
times will be affected accordingly. If the EEPROM or Flash are written, do not calibrate to more
than 8.8 MHz. Otherwise, the EEPROM or Flash write may fail.
The CAL7 bit determines the range of operation for the oscillator. Setting this bit to 0 gives the
lowest frequency range, setting this bit to 1 gives the highest frequency range. The two fre-
quency ranges are overlapping, in other words a setting of OSCCAL = 0x7F gives a higher
frequency than OSCCAL = 0x80.
The CAL6..0 bits are used to tune the frequency within the selected range. A setting of 0x00
gives the lowest frequency in that range, and a setting of 0x7F gives the highest frequency in the
range. Incrementing CAL6..0 by 1 will give a frequency increment of less than 2% in the fre-
quency range 7.3 - 8.1 MHz.
The device can utilize a external clock source as shown in
external clock, the CKSEL Fuses must be programmed as shown in
Bit
Read/Write
Initial Value
Power Conditions
BOD enabled
Fast rising power
Slowly rising power
1. The device is shipped with this option selected.
Start-up times for the internal calibrated RC Oscillator clock selection
7
CAL7
R/W
Device Specific Calibration Value
6
CAL6
R/W
Start-up Time from Power-
down and Power-save
5
CAL5
R/W
Reserved
6 CK
6 CK
6 CK
4
CAL4
R/W
3
CAL3
R/W
2
CAL2
R/W
Figure
Additional Delay from
Reset (V
14CK + 65 ms
14CK + 4.1 ms
AT90USB64/128
6-3. To run the device on an
Table
1
CAL1
R/W
14CK
CC
= 5.0V)
6-1.
(1)
0
CAL0
R/W
SUT1..0
OSCCAL
01
10
11
00
45