AT43USB320A-AC Atmel, AT43USB320A-AC Datasheet - Page 60

• Manufacturer Part Number: AT43USB320A-AC
• Description: IC USB MCU EMBED HUB AVR 100LQFP
• Manufacturer: Atmel
• Series: AVR®r

Specifications of AT43USB320A-AC

• Applications: USB Hub/Microcontroller
• Core Processor: AVR
• Controller Series: AT43USB
• Ram Size: 512 x 8
• Interface: SPI Serial, USB, UART
• Number Of I /o: 32
• Voltage - Supply: 4.4 V ~ 5.25 V
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Package / Case: 100-LQFP
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Program Memory Type: -

isters, one for transmitted data and one for received data. When UDR is read, the Receive
Data register is accessed, and when UDR is written, the Transmit Data register is accessed.
If, after having received a character, the UDR register has not been read since the last
receive, the OverRun (OR) flag in UCR is set. This means that the last data byte shifted into
the shift register could not be transferred to UDR and has been lost. The OR bit is buffered
and is updated when the valid data byte in UDR is read. Thus, the user should always check
the OR bit after reading the UDR register in order to detect any overruns if the baud rate is
high or CPU load is high.
When the RXEN bit in the UCR register is cleared (zero), the receiver is disabled. This means
that the PDO pin can be used as a general I/O pin. When RXEN is set, the UART Receiver will
be connected to PDO, which is forced to be an input pin regardless of the setting of the DDDO
bit in DDRD. When PDO is forced to input by the UART, the PORTDO bit can still be used to
control the pull-up resistor on the pin.
Figure 20. UART Receiver
Figure 21. Sampling Received Data
AT43USB320A
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