Atmel Evaluation Kit for AT32uC3A0512, 32-Bit AVR Microcontroller Atmel ATEVK1105 ATEVK1105 Data Sheet
Product codes
ATEVK1105
798
AT32UC3A
None.
41.2.9
USART
1. ISO7816 info register US_NER cannot be read
The NER register always returns zero.
Fix/Workaround
None
Fix/Workaround
None
41.2.10
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.
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.
Fix/Workaround
When using the STCOND instruction, clear SREG[L] in the stacked value of SR before
returning from interrupts with RETE.
3. Exceptions when system stack is protected by MPU
RETS behaves incorrectly when MPU is enabled and MPU is configured so that
system stack is not readable in unprivileged mode.
Fix/Woraround
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 mt-
sr 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.
system stack is not readable in unprivileged mode.
Fix/Woraround
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 mt-
sr 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.
1.
Reading from on-chip flash may fail after a flash fuse write operation (FLASHC LP,
UP, WGPB, EGPB, SSB, PGPFB, EAGPF commands).
UP, WGPB, EGPB, SSB, PGPFB, EAGPF commands).
After a flash fuse write operation (FLASHC LP, UP, WGPB, EGPB, SSB, PGPFB, EAGPF
commands), the following flash read access may return corrupted data. This erratum does
not affect write operations to regular flash memory.
commands), the following flash read access may return corrupted data. This erratum does
not affect write operations to regular flash memory.
Fix/Workaround
The flash fuse write operation (FLASHC LP, UP, WGPB, EGPB, SSB, PGPFB, EAGPF
commands) must be issued from internal RAM. After the write operation, perform a dummy
flash page write operation (FLASHC WP). Content and location of this page is not important
and filling the write buffer with all one (FFh) will leave the current flash content unchanged. It
is then safe to read and fetch code from the flash.
commands) must be issued from internal RAM. After the write operation, perform a dummy
flash page write operation (FLASHC WP). Content and location of this page is not important
and filling the write buffer with all one (FFh) will leave the current flash content unchanged. It
is then safe to read and fetch code from the flash.
41.2.11 FLASHC
32058K
AVR32-01/12