ATSAM3X4EA-AU Atmel, ATSAM3X4EA-AU Datasheet - Page 792

• Manufacturer Part Number: ATSAM3X4EA-AU
• Description: ARM Microcontrollers - MCU QFP144,GREEN, IND TEMP, MRL A
• Manufacturer: Atmel

Specifications of ATSAM3X4EA-AU

• Rohs: yes
• Core: ARM Cortex M3
• Processor Series: SAM3X
• Data Bus Width: 32 bit
• Maximum Clock Frequency: 84 MHz
• Program Memory Size: 256 KB
• Data Ram Size: 64 KB
• On-chip Adc: Yes
• Operating Supply Voltage: 2.4 V to 3.6 V
• Operating Temperature Range: - 40 C to +85 C
• Package / Case: LQFP-144
• Mounting Style: SMD/SMT
• Factory Pack Quantity: 60

36.7.3.3
792
792
Drift Compensation
SAM3X/A
SAM3X/A
Asynchronous Receiver
Figure 36-10. Start Frame Delimiter
Drift compensation is available only in 16X oversampling mode. An hardware recovery system
allows a larger clock drift. To enable the hardware system, the bit in the USART_MAN register
must be set. If the RXD edge is one 16X clock cycle from the expected edge, this is considered
as normal jitter and no corrective actions is taken. If the RXD event is between 4 and 2 clock
cycles before the expected edge, then the current period is shortened by one clock cycle. If the
RXD event is between 2 and 3 clock cycles after the expected edge, then the current period is
lengthened by one clock cycle. These intervals are considered to be drift and so corrective
actions are automatically taken.
Figure 36-11. Bit Resynchronization
If the USART is programmed in asynchronous operating mode (SYNC = 0), the receiver over-
samples the RXD input line. The oversampling is either 16 or 8 times the Baud Rate clock,
depending on the OVER bit in the Mode Register (US_MR).
Oversampling
16x Clock
Sampling
point
RXD
Manchester
Manchester
Manchester
encoded
encoded
encoded
data
data
data
Preamble Length
Txd
Txd
Txd
Synchro.
Error
is set to 0
Synchro.
SFD
SFD
SFD
Jump
DATA
One bit start frame delimiter
Expected edge
Tolerance
start frame delimiter
start frame delimiter
DATA
DATA
Command Sync
Jump
Sync
Data Sync
Synchro.
11057B–ATARM–28-May-12
11057B–ATARM–28-May-12
Error