AT32UC3L0256 Atmel Corporation, AT32UC3L0256 Datasheet - Page 381

• Manufacturer Part Number: AT32UC3L0256
• Manufacturer: Atmel Corporation

Specifications of AT32UC3L0256

• Flash (kbytes): 256 Kbytes
• Pin Count: 48
• Max. Operating Frequency: 50 MHz
• Cpu: 32-bit AVR
• # Of Touch Channels: 17
• Hardware Qtouch Acquisition: Yes
• Max I/o Pins: 36
• Ext Interrupts: 36
• Usb Speed: No
• Usb Interface: No
• Spi: 5
• Twi (i2c): 2
• Uart: 4
• Lin: 4
• Graphic Lcd: No
• Video Decoder: No
• Camera Interface: No
• Adc Channels: 8
• Adc Resolution (bits): 12
• Adc Speed (ksps): 460
• Analog Comparators: 8
• Resistive Touch Screen: No
• Temp. Sensor: Yes
• Crypto Engine: No
• Sram (kbytes): 16
• Self Program Memory: YES
• Dram Memory: No
• Nand Interface: No
• Picopower: Yes
• Temp. Range (deg C): -40 to 85
• I/o Supply Class: 1.62 to 3.6
• Operating Voltage (vcc): 1.62 to 3.6
• Fpu: No
• Mpu / Mmu: Yes / No
• Timers: 6
• Output Compare Channels: 18
• Input Capture Channels: 12
• Pwm Channels: 35
• 32khz Rtc: Yes
• Calibrated Rc Oscillator: Yes

Figure 19-3. Fractional Baud Rate Generator
19.6.1.4
19.6.2
32145A–12/2011
CLK_USART/DIV
CLK
CLK_USART
Reserved
Receiver and Transmitter Control
Baud Rate in Synchronous and SPI Mode
USCLKS
1
2
3
0
If the USART is configured to operate in synchronous mode, the selected clock is divided by the
BRGR.CD field. This does not apply when CLK is selected.
When CLK is selected the external frequency must be at least 4.5 times lower than the system
clock, and when either CLK or CLK_USART/DIV are selected, CD must be even to ensure a
50/50 duty cycle. If CLK_USART is selected, the generator ensures this regardless of value.
After a reset, the transceiver is disabled. The receiver/transmitter is enabled by writing a one to
either the Receiver Enable, or Transmitter Enable bit in the Control Register (CR.RXEN, or
CR.TXEN). They may be enabled together and can be configured both before and after they
have been enabled. The user can reset the USART receiver/transmitter at any time by writing a
one to either the Reset Receiver (CR.RSTRX), or Reset Transmitter (CR.RSTTX) bit. This soft-
ware reset clears status bits and resets internal state machines, immediately halting any
communication. The user interface configuration registers will retain their values.
The user can disable the receiver/transmitter by writing a one to either the Receiver Disable, or
Transmitter Disable bit (CR.RXDIS, or CR.TXDIS). If the receiver is disabled during a character
reception, the USART will wait for the current character to be received before disabling. If the
transmitter is disabled during transmission, the USART will wait until both the current character
and the character stored in the Transmitter Holding Register (THR) are transmitted before dis-
abling. If a timeguard has been implemented it will remain functional during the transaction.
BaudRate
16-bit Counter
CD
Modulus
=
Control
FP
SelectedClock
------------------------------------- -
CD
glitch-free
USCLKS = 3
logic
FP
SYNC
0
>1
CD
0
1
0
1
AT32UC3L0128/256
OVER
Sampling
Divider
FIDI
0
1
SYNC
CLK
BaudRate
Sampling
Clock
Clock
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