AT90USB1286-AU Atmel, AT90USB1286-AU Datasheet - Page 184

• Manufacturer Part Number: AT90USB1286-AU
• Description: MCU AVR 128K FLASH 16MHZ 64TQFP
• Manufacturer: Atmel
• Series: AVR® 90USBr

Specifications of AT90USB1286-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
• 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
• 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
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 10 bit, 8 Channel
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

18.2.2
184
AT90USB64/128
Double Speed Operation (U2Xn)
Table 18-1
ing the UBRRn value for each mode of operation using an internally generated clock source.
Table 18-1.
Note:
Some examples of UBRRn values for some system clock frequencies are found in
page
The transfer rate can be doubled by setting the U2Xn bit in UCSRnA. Setting this bit only has
effect for the asynchronous operation. Set this bit to zero when using synchronous operation.
Setting this bit will reduce the divisor of the baud rate divider from 16 to 8, effectively doubling
the transfer rate for asynchronous communication. Note however that the Receiver will in this
case only use half the number of samples (reduced from 16 to 8) for data sampling and clock
recovery, and therefore a more accurate baud rate setting and system clock are required when
this mode is used. For the Transmitter, there are no downsides.
Operating Mode
Asynchronous Normal
mode (U2Xn = 0)
Asynchronous Double
Speed mode (U2Xn =
1)
Synchronous Master
mode
203.
BAUD
f
UBRRn
OSC
1. The baud rate is defined to be the transfer rate in bit per second (bps)
contains equations for calculating the baud rate (in bits per second) and for calculat-
Equations for Calculating Baud Rate Register Setting
Baud rate (in bits per second, bps)
System Oscillator clock frequency
Contents of the UBRRHn and UBRRLn Registers, (0-4095)
BAUD
BAUD
BAUD
Equation for Calculating
Baud Rate
=
=
=
----------------------------------------- -
16 UBRRn
-------------------------------------- -
8 UBRRn
-------------------------------------- -
2 UBRRn
(
(
(
f
f
f
OSC
OSC
OSC
(1)
+
+
+
1
1
1
)
)
)
UBRRn
UBRRn
UBRRn
Equation for Calculating
UBRR Value
=
=
=
----------------------- - 1
16BAUD
------------------- - 1
8BAUD
------------------- - 1
2BAUD
f
f
f
OSC
OSC
OSC
–
–
–
Table 18-9 on
7593K–AVR–11/09