AT90USB647-MU Atmel, AT90USB647-MU Datasheet - Page 448

• Manufacturer Part Number: AT90USB647-MU
• Description: MCU, 8BIT, 64K FLASH, USB, 64QFN
• Manufacturer: Atmel

Specifications of AT90USB647-MU

• Controller Family/series: AT90
• No. Of I/o's: 48
• Eeprom Memory Size: 2KB
• Ram Memory Size: 4KB
• Cpu Speed: 16MHz
• No. Of: RoHS Compliant
• Core Size: 8bit
• Program Memory Size: 64KB
• Oscillator Type: External, Internal
• Package: 64QFN EP
• Device Core: AVR
• Family Name: AT90
• Maximum Speed: 20 MHz
• Ram Size: 4 KB
• Operating Supply Voltage: 3.3|5 V
• Data Bus Width: 8 Bit
• Program Memory Type: Flash
• Number Of Programmable I/os: 48
• Interface Type: SPI/TWI/USART/USB
• On-chip Adc: 8-chx10-bit
• Operating Temperature: -40 to 85 °C
• Number Of Timers: 4
• Lead Free Status / Rohs Status: Details

37. AT90USB647/6 Errata.
448
AT90USB64/128
6.
5. USB Eye Diagram violation in low-speed mode
4. Transient perturbation in USB suspend mode generates overconsumption
3. Spike on TWI pins when TWI is enabled
2. High current consumption in sleep mode
• Incorrect interrupt routine exection for VBUSTI, IDTI interrupts flags
• USB Eye Diagram violation in low-speed mode
• Transient perturbation in USB suspend mode generates over consumption
• Spike on TWI pins when TWI is enabled
• High current consumption in sleep mode
• Async timer interrupt wake up from sleep generate multiple interrupts
A software workaround is to wait beforeperforming the sleep instruction: until
TCNT2>OCR2+1.
The CPU core may incorrectly execute the interrupt vector related to the VBUSTI and IDTI
interrupt flags.
Problem fix/workaround
Do not enable these interrupts, firmware must process these USB events by polling VBUSTI
and IDTI flags.
The low to high transition of D- violates the USB eye diagram specification when transmitting
with low-speed signaling.
Problem fix/workaround
None.
In device mode and when the USB is suspended, transient perturbation received on the
USB lines generates a wake up state. However the idle state following the perturbation does
not set the SUSPI bit anymore. The internal USB engine remains in suspend mode but the
USB differential receiver is still enabled and generates a typical 300µA extra-power con-
sumption. Detection of the suspend state after the transient perturbation should be
performed by software (instead of reading the SUSPI bit).
Problem fix/workaround
USB waiver allows bus powered devices to consume up to 2.5mA in suspend state.
100 ns negative spike occurs on SDA and SCL pins when TWI is enabled.
Problem Fix/workaround
No known workaround, enable AT90USB64/128 TWI first versus the others nodes of the
TWI network.
Incorrect CPU behavior for VBUSTI and IDTI interrupts routines
7593K–AVR–11/09