AT91CAP7E-NA-ZJ Atmel, AT91CAP7E-NA-ZJ Datasheet - Page 374

• Manufacturer Part Number: AT91CAP7E-NA-ZJ
• Description: MCU CAP7 FPGA 225LFBGA
• Manufacturer: Atmel
• Series: CAP™r

Specifications of AT91CAP7E-NA-ZJ

• Core Processor: ARM7
• Core Size: 16/32-Bit
• Speed: 80MHz
• Connectivity: EBI/EMI, FPGA, IrDA, SPI, UART/USART, USB
• Peripherals: DMA, POR, PWM, WDT
• Number Of I /o: 32
• Program Memory Size: 256KB (256K x 8)
• Program Memory Type: ROM
• Ram Size: 160K x 8
• Voltage - Supply (vcc/vdd): 1.08 V ~ 1.32 V
• Data Converters: A/D 8x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 225-LFBGA
• Processor Series: AT91Mx
• Core: ARM7TDMI
• Data Bus Width: 32 bit
• 3rd Party Development Tools: JTRACE-ARM-2M, MDK-ARM, RL-ARM, ULINK2
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Lead Free Status / Rohs Status: Details

29.6.6
Figure 29-36. Typical Connection to a RS485 Bus
Figure 29-37. Example of RTS Drive with Timeguard
374
AT91CAP7E
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 29-37
USART
Start
Bit
RXD
TXD
RTS
D0
gives an example of the RTS waveform during a character transmission
D1
D2
D3
D4
D5
D6
D7
Parity
Bit
Stop
Bit
Differential
Bus
Figure
TG = 4
29-36.
8549A–CAP–10/08