Техническая Спецификация для Atmel Evaluation Kit for AT32uC3A0512, 32-Bit AVR Microcontroller Atmel ATEVK1105 ATEVK1105
Модели
ATEVK1105
811
AT32UC3A
12. CPU cannot operate on a divided slow clock (internal RC oscillator)
Fix/Workaround
Do not run the CPU on a divided slow clock.
Do not run the CPU on a divided slow clock.
13. 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.
14. 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.
15. 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 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.
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 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.
41.5.6
SDRAMC
1. Code execution from external SDRAM does not work
Code execution from SDRAM does not work.
Fix/Workaround
Do not run code from SDRAM.
Do not run code from SDRAM.
2. SDRAM SDCKE rise at the same time as SDCK while exiting self-refresh mode
SDCKE rise at the same time as SDCK while exiting self-refresh mode.
Fix/Workaround
None.
None.
41.5.7
USART
1. USART Manchester Encoder Not Working
Manchester encoding/decoding is not working.
Fix/Workaround
Do not use manchester encoding.
Do not use manchester encoding.
32058K
AVR32-01/12