AT91SAM9R64-CU Atmel, AT91SAM9R64-CU Datasheet - Page 468

• 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 34-31. T = 0 Protocol without Parity Error
Figure 34-32. T = 0 Protocol with Parity Error
6289C–ATARM–28-May-09
Baud Rate
Receive Error Counter
Receive NACK Inhibit
Transmit Character Repetition
Baud Rate
Clock
I/O
Clock
RXD
Start
Bit
Start
Bit
D0
If a parity error is detected by the receiver, it drives the I/O line at 0 during the guard time, as
shown in
the character lasts 1 bit time more, as the guard time length is the same and is added to the
error bit time which lasts 1 bit time.
When the USART is the receiver and it detects an error, it does not load the erroneous character
in the Receive Holding Register (US_RHR). It appropriately sets the PARE bit in the Status Reg-
ister (US_SR) so that the software can handle the error.
The USART receiver also records the total number of errors. This can be read in the Number of
Error (US_NER) register. The NB_ERRORS field can record up to 255 errors. Reading US_NER
automatically clears the NB_ERRORS field.
The USART can also be configured to inhibit an error. This can be achieved by setting the
INACK bit in the Mode Register (US_MR). If INACK is at 1, no error signal is driven on the I/O
line even if a parity bit is detected, but the INACK bit is set in the Status Register (US_SR). The
INACK bit can be cleared by writing the Control Register (US_CR) with the RSTNACK bit at 1.
Moreover, if INACK is set, the erroneous received character is stored in the Receive Holding
Register, as if no error occurred. However, the RXRDY bit does not raise.
When the USART is transmitting a character and gets a NACK, it can automatically repeat the
character before moving on to the next one. Repetition is enabled by writing the
MAX_ITERATION field in the Mode Register (US_MR) at a value higher than 0. Each character
can be transmitted up to eight times; the first transmission plus seven repetitions.
If MAX_ITERATION does not equal zero, the USART repeats the character as many times as
the value loaded in MAX_ITERATION.
D0
D1
D1
Figure
D2
D2
34-32. This error bit is also named NACK, for Non Acknowledge. In this case,
D3
D3
D4
D4
D5
AT91SAM9R64/RL64 Preliminary
D5
D6
D6
D7
D7
Parity
Bit
Parity
Bit
Time 1
Guard
Time 1
Guard
Error
Time 2
Guard
Time 2
Guard
Start
Next
Bit
Start
Bit
Repetition
D0
D1
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