AT32UC3B1256-Z1UR Atmel, AT32UC3B1256-Z1UR Datasheet - Page 660

• Manufacturer Part Number: AT32UC3B1256-Z1UR
• Description: MCU AVR32 256K FLASH 48-QFN
• Manufacturer: Atmel
• Series: AVR®32 UC3r

Specifications of AT32UC3B1256-Z1UR

• Package / Case: 48-QFN Exposed Pad
• Voltage - Supply (vcc/vdd): 1.65 V ~ 1.95 V
• Operating Temperature: -40°C ~ 85°C
• Speed: 60MHz
• Number Of I /o: 28
• Core Processor: AVR
• Program Memory Type: FLASH
• Ram Size: 32K x 8
• Program Memory Size: 256KB (256K x 8)
• Data Converters: A/D 6x10b
• Oscillator Type: Internal
• Peripherals: Brown-out Detect/Reset, DMA, POR, PWM, WDT
• Connectivity: I²C, IrDA, SPI, SSC, UART/USART, USB
• Core Size: 32-Bit
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -

31.2.1.12
32059J–12/2010
USART
3. Exceptions when system stack is protected by MPU
4. Privilege violation when using interrupts in application mode with protected system
1. ISO7816 info register US_NER cannot be read
2. ISO7816 Mode T1: RX impossible after any TX
3. The RTS output does not function correctly in hardware handshaking mode
4. Corruption after receiving too many bits in SPI slave mode
RETS behaves incorrectly when MPU is enabled and MPU is configured so thatsystem
stack is not readable in unprivileged mode.
Fix/Workaround
Workaround 1: Make system stack readable in unprivileged mode,
or
Workaround 2: Return from supervisor mode using rete instead of rets. This requires: 1.
Changing the mode bits from 001b to 110b before issuing the instruction.
Updating the mode bits to the desired value must be done using a single mtsr instruction so
it is done atomically. Even if this step is described in general as not safe in the UC technical
reference guide, it is safe in this very specific case.
2. Execute the RETE instruction.
stack
If the system stack is protected by the MPU and an interrupt occurs in application mode, an
MPU DTLB exception will occur.
Fix/Workaround
Make a DTLB Protection (Write) exception handler which permits the interrupt request to be
handled in privileged mode.
The NER register always returns zero.
Fix/Workaround
None.
RX impossible after any TX.
Fix/Workaround
SOFT_RESET on RX+ Config US_MR + Config_US_CR
The RTS signal is not generated properly when the USART receives data in hardware hand-
shaking mode. When the Peripheral DMA receive buffer becomes full, the RTS output
should go high, but it will stay low.
Fix/Workaround
Do not use the hardware handshaking mode of the USART. If it is necessary to drive the
RTS output high when the Peripheral DMA receive buffer becomes full, use the normal
mode of the USART. Configure the Peripheral DMA Controller to signal an interrupt when
the receive buffer is full. In the interrupt handler code, write a one to the RTSDIS bit in the
USART Control Register (CR). This will drive the RTS output high. After the next DMA trans-
fer is started and a receive buffer is available, write a one to the RTSEN bit in the USART
CR so that RTS will be driven low.
If the USART is in SPI slave mode and receives too much data bits (ex: 9bitsinstead of 8
bits) by the the SPI master, an error occurs . After that, the next reception may be corrupted
even if the frame is correct and the USART has been disabled, reseted by a soft reset and
re-enabled.
Fix/Workaround
None.
AT32UC3B
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