AT90USB646-MUR Atmel, AT90USB646-MUR Datasheet - Page 268

• Manufacturer Part Number: AT90USB646-MUR
• Description: MCU AVR 64K FLASH 16MHZ 64QFN
• Manufacturer: Atmel
• Series: AVR® 90USBr

Specifications of AT90USB646-MUR

• 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: 64KB (64K x 8)
• Program Memory Type: FLASH
• Eeprom Size: 2K x 8
• Ram Size: 4K 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-VQFN Exposed Pad, 64-HVQFN, 64-SQFN, 64-DHVQFN
• Data Bus Width: 8 bit
• Data Ram Size: 4 KB
• Interface Type: SPI, UART
• Maximum Clock Frequency: 20 MHz
• Number Of Programmable I/os: 48
• Number Of Timers: 4
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 10 bit, 8 Channel
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

22.4
22.5
22.6
268
USB reset
Endpoint selection
Endpoint activation
AT90USB64/128
The data toggle field remains unchanged.
The other registers remain unchanged.
The endpoint configuration remains active and the endpoint is still enabled.
The endpoint reset may be associated with a clear of the data toggle command (RSTDT bit) as
an answer to the CLEAR_FEATURE USB command.
When an USB reset is detected on the USB line, the next operations are performed by the
controller:
Prior to any operation performed by the CPU, the endpoint must first be selected. This is done
by setting the EPNUM2:0 bits (UENUM register) with the endpoint number which will be man-
aged by the CPU.
The CPU can then access to the various endpoint registers and data.
The endpoint is maintained under reset as long as the EPEN bit is not set.
The following flow must be respected in order to activate an endpoint:
• the UEINTX, UESTA0X and UESTA1X are restored to their reset value.
• all the endpoints are disabled
• the default control endpoint remains configured (see Section 22.3, page 267 for more
details).
7593K–AVR–11/09