AT91SAM9R64-CU Atmel, AT91SAM9R64-CU Datasheet - Page 454

• Manufacturer Part Number: AT91SAM9R64-CU
• Description: MCU ARM9 64K SRAM 144-LFBGA
• Manufacturer: Atmel
• Series: AT91SAMr

Specifications of AT91SAM9R64-CU

• Core Processor: ARM9
• Core Size: 16/32-Bit
• Speed: 240MHz
• Connectivity: EBI/EMI, I²C, MMC, SPI, SSC, UART/USART, USB
• Peripherals: AC'97, POR, PWM, WDT
• Number Of I /o: 49
• Program Memory Size: 32KB (32K x 8)
• Program Memory Type: ROM
• Ram Size: 72K x 8
• Voltage - Supply (vcc/vdd): 1.08 V ~ 1.32 V
• Data Converters: A/D 3x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 144-LFBGA
• Processor Series: AT91SAMx
• Core: ARM926EJ-S
• Data Bus Width: 32 bit
• Data Ram Size: 64 KB
• Interface Type: 2-Wire, SPI, SSC, USART
• Maximum Clock Frequency: 240 MHz
• Number Of Programmable I/os: 118
• Number Of Timers: 4
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• 3rd Party Development Tools: JTRACE-ARM-2M, MDK-ARM, RL-ARM, ULINK2
• Development Tools By Supplier: AT91SAM-ICE, AT91-ISP, AT91SAM9RL-EK
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 10 bit, 3 Channel
• Controller Family/series: AT91SAM9xxx
• No. Of I/o's: 49
• Ram Memory Size: 64KB
• Cpu Speed: 240MHz
• No. Of Timers: 3
• Rohs Compliant: Yes
• Package: 144LFBGA
• Device Core: ARM926EJ-S
• Family Name: 91S
• Maximum Speed: 240 MHz
• Operating Supply Voltage: 1.8|3.3 V
• For Use With: AT91SAM-ICE - EMULATOR FOR AT91 ARM7/ARM9
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

Figure 34-11. Bit Resynchronization
34.6.3.3
6289C–ATARM–28-May-09
Asynchronous Receiver
Oversampling
16x Clock
Sampling
point
RXD
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).
The receiver samples the RXD line. If the line is sampled during one half of a bit time at 0, a start
bit is detected and data, parity and stop bits are successively sampled on the bit rate clock.
If the oversampling is 16, (OVER at 0), a start is detected at the eighth sample at 0. Then, data
bits, parity bit and stop bit are sampled on each 16 sampling clock cycle. If the oversampling is 8
(OVER at 1), a start bit is detected at the fourth sample at 0. Then, data bits, parity bit and stop
bit are sampled on each 8 sampling clock cycle.
The number of data bits, first bit sent and parity mode are selected by the same fields and bits
as the transmitter, i.e. respectively CHRL, MODE9, MSBF and PAR. For the synchronization
mechanism only, the number of stop bits has no effect on the receiver as it considers only one
stop bit, regardless of the field NBSTOP, so that resynchronization between the receiver and the
transmitter can occur. Moreover, as soon as the stop bit is sampled, the receiver starts looking
for a new start bit so that resynchronization can also be accomplished when the transmitter is
operating with one stop bit.
Figure 34-12
operates in asynchronous mode.
and
Synchro.
Error
Figure 34-13
Synchro.
Jump
illustrate start detection and character reception when USART
AT91SAM9R64/RL64 Preliminary
Expected edge
Tolerance
Jump
Sync
Synchro.
Error
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