Datasheet

78
32059L–AVR32–01/2012
AT32UC3B
- Processor and Architecture
1. LDM instruction with PC in the register list and without ++ increments Rp
For LDM with PC in the register list:
the instruction behaves as if the ++ field is always set, ie
the pointer is always updated. This happens even if the ++ field is cleared. Specifically, the
increment of the pointer is done in parallel with the testing of R12.
Fix/Workaround
None.
2. RETE instruction does not clear SREG[L] from interrupts
The RETE instruction clears SREG[L] as expected from exceptions.
Fix/Workaround
When using the STCOND instruction, clear SREG[L] in the stacked value of SR before
returning from interrupts with RETE.
3. Privilege violation when using interrupts in application mode with protected system
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.
4. USART
5. ISO7816 info register US_NER cannot be read
The NER register always returns zero.
Fix/Workaround
None.
6. ISO7816 Mode T1: RX impossible after any TX
RX impossible after any TX.
Fix/Workaround
SOFT_RESET on RX+ Config US_MR + Config_US_CR.
7. The RTS output does not function correctly in hardware handshaking mode
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.
8. Corruption after receiving too many bits in SPI slave mode
If the USART is in SPI slave mode and receives too much data bits (ex: 9bitsinstead of 8
bits) by the SPI master, an error occurs. After that, the next reception may be corrupted