AT90USB646-MUR Atmel, AT90USB646-MUR Datasheet - Page 260

• 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

21.10.1
21.10.2
21.11 ID detection
260
AT90USB64/128
Peripheral mode
Host mode
Figure 21-16. Plug-in Detection Input Block Diagram
The control logic of the VBUS pad outputs a signal regarding the VBUS voltage level :
The USB peripheral cannot attach to the bus while VBUS bit is not set.
The Host must use the UVCON pin to drive an external power switch or regulator that powers
the Vbus line. The UVCON pin is automatically asserted and set high by hardware when
UVCONE and VBUSREQ bits are set by firmware.
If a device connects (pull-up on DP or DM) within 300ms of Vbus delivery, the DCONNI flag will
rise. But, once VBUSREQ bit has been set, if no peripheral connection is detected within 300ms,
the BCERRI flag (and interrupt) will rise and Vbus delivery will be stopped (UVCON cleared).
If that behavior represents a limitation for the Host application, the following work-around may be
used :
The ID pin transition is detected thanks to the following architecture:
• The “Session_valid” signal is active high when the voltage on the VBUS pad is higher or
• The “Vbus_valid” signal is active high when the voltage on the VBUS pad is higher or equal to
• The VBUS status bit is set when VBUS is greater than “Vbus_valid”. The VBUS status bit is
• The VBUSTI flag is set each time the VBUS bit state changes.
1. UVCONE and VBUSREQ must be cleared
2. VBUSHWC must be set (to disable hardware control of UVCON pin)
3. PORTE,7 pin (alternate function of UVCON pin) must be set by firmware
4. a device connection will be detected thanks to the SRPI flag (that may usually be used
equal to 1.4V. If lower than 1.4V, the signal is not active.
4.4V. If lower than 4.4V, the signal is not active.
cleared when VBUS falls below “Session_valid” (hysteresis behavior).
to detect a DP/DM pulse sent by an OTG B-Device that requests a new session)
VBUS
Pad logic
VDD
VSS
Vbus_valid
Session_valid
VBus_pulsing
VBus_discharge
Logic
USBSTA.0
VBUS
7593K–AVR–11/09
VBUSTI
USBINT.0