AT90USB646-MU Atmel, AT90USB646-MU Datasheet - Page 186

• Manufacturer Part Number: AT90USB646-MU
• Description: IC AVR MCU 64K 64QFN
• Manufacturer: Atmel
• Series: AVR® 90USBr

Specifications of AT90USB646-MU

• 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
• Processor Series: 90USB
• Core: AVR
• Data Bus Width: 8 bit
• Data Ram Size: 4 KB
• Interface Type: SPI, TWI, USART, USB
• Maximum Clock Frequency: 20 MHz
• Number Of Programmable I/os: 48
• Number Of Timers: 4
• Operating Supply Voltage: 5 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Minimum Operating Temperature: - 40 C
• Operating Temperature Range: - 40 C to + 85 C
• Cpu Family: AT90
• Device Core: AVR
• Device Core Size: 8b
• Frequency (max): 20MHz
• Total Internal Ram Size: 4KB
• # I/os (max): 48
• Number Of Timers - General Purpose: 4
• Operating Supply Voltage (typ): 3.3/5V
• Operating Supply Voltage (max): 5.5V
• Operating Supply Voltage (min): 2.7V
• On-chip Adc: 8-chx10-bit
• Instruction Set Architecture: RISC
• Operating Temp Range: -40C to 85C
• Operating Temperature Classification: Industrial
• Mounting: Surface Mount
• Pin Count: 64
• Package Type: QFN EP
• For Use With: ATSTK600-TQFP64 - STK600 SOCKET/ADAPTER 64-TQFP770-1007 - ISP 4PORT ATMEL AVR MCU SPI/JTAGATSTK525 - KIT STARTER FOR AT90USBAT90USBKEY2 - KIT DEMO FOR AT90USB
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: AT90USB646-16MU; AT90USB646-16MU

18.3.1
186
AT90USB64/128
Parity Bit Calculation
A frame starts with the start bit followed by the least significant data bit. Then the next data bits,
up to a total of nine, are succeeding, ending with the most significant bit. If enabled, the parity bit
is inserted after the data bits, before the stop bits. When a complete frame is transmitted, it can
be directly followed by a new frame, or the communication line can be set to an idle (high) state.
Figure 18-4
optional.
Figure 18-4. Frame Formats
must be
The frame format used by the USART is set by the UCSZn2:0, UPMn1:0 and USBSn bits in
UCSRnB and UCSRnC. The Receiver and Transmitter use the same setting. Note that changing
the setting of any of these bits will corrupt all ongoing communication for both the Receiver and
Transmitter.
The USART Character SiZe (UCSZn2:0) bits select the number of data bits in the frame. The
USART Parity mode (UPMn1:0) bits enable and set the type of parity bit. The selection between
one or two stop bits is done by the USART Stop Bit Select (USBSn) bit. The Receiver ignores
the second stop bit. An FE (Frame Error) will therefore only be detected in the cases where the
first stop bit is zero.
The parity bit is calculated by doing an exclusive-or of all the data bits. If odd parity is used, the
result of the exclusive or is inverted. The relation between the parity bit and data bits is as
follows::
If used, the parity bit is located between the last data bit and first stop bit of a serial frame.
St
(n)
P
Sp
IDLE
P
P
d
odd
n
even
illustrates the possible combinations of the frame formats. Bits inside brackets are
(IDLE)
St
Start bit, always low.
Data bits (0 to 8).
Parity bit. Can be odd or even.
Stop bit, always high.
No transfers on the communication line (RxDn or TxDn). An IDLE line
high.
Parity bit using even parity
Parity bit using odd parity
Data bit n of the character
P
0
P
even
odd
1
=
=
d
d
2
n 1
n 1
–
–
3
⊕
⊕
…
…
4
⊕
⊕
FRAME
[5]
d
d
3
3
⊕
⊕
[6]
d
d
2
2
⊕
⊕
[7]
d
d
1
1
[8]
⊕
⊕
d
d
0
0
[P]
⊕
⊕
0
1
Sp1 [Sp2]
(St / IDLE)
7593K–AVR–11/09