AT91SAM9R64-CU Atmel, AT91SAM9R64-CU Datasheet - Page 472

• 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

34.6.6
Figure 34-36. Typical Connection to a RS485 Bus
Figure 34-37. Example of RTS Drive with Timeguard
6289C–ATARM–28-May-09
RS485 Mode
The USART features the RS485 mode to enable line driver control. While operating in RS485
mode, the USART behaves as though in asynchronous or synchronous mode and configuration
of all the parameters is possible. The difference is that the RTS pin is driven high when the
transmitter is operating. The behavior of the RTS pin is controlled by the TXEMPTY bit. A typical
connection of the USART to a RS485 bus is shown in
The USART is set in RS485 mode by programming the USART_MODE field in the Mode Regis-
ter (US_MR) to the value 0x1.
The RTS pin is at a level inverse to the TXEMPTY bit. Significantly, the RTS pin remains high
when a timeguard is programmed so that the line can remain driven after the last character com-
pletion.
when the timeguard is enabled.
Baud Rate
TXEMPTY
US_THR
TXRDY
Clock
Write
TXD
RTS
Figure 34-37
USART
Start
Bit
D0
RXD
TXD
RTS
gives an example of the RTS waveform during a character transmission
D1
D2
D3
D4
AT91SAM9R64/RL64 Preliminary
D5
D6
D7
Parity
Bit
Stop
Bit
Differential
TG = 4
Bus
Figure
34-36.
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