Datasheet

82
32072SH–AVR32–10/2012
AT32UC3A3
Fix/Workaround
Before going to sleep modes where the system RC oscillator is stopped, make sure that the
factor between the CPU/HSB and PBx frequencies is less than or equal to 4.
10.2.9 PDCA
PCONTROL.CHxRES is non-functional
PCONTROL.CHxRES is non-functional. Counters are reset at power-on, and cannot be
reset by software.
Fix/Workaround
Software needs to keep history of performance counters.
Transfer error will stall a transmit peripheral handshake interface
If a transfer error is encountered on a channel transmitting to a peripheral, the peripheral
handshake of the active channel will stall and the PDCA will not do any more transfers on
the affected peripheral handshake interface.
Fix/Workaround
Disable and then enable the peripheral after the transfer error.
10.2.10 AES
URAD (Unspecified Register Access Detection Status) does not detect read accesses
to the write-only KEYW[5..8]R registers
Fix/Workaround
None.
10.2.11 HMATRIX
In the PRAS and PRBS registers, the MxPR fields are only two bits
In the PRAS and PRBS registers, the MxPR fields are only two bits wide, instead of four bits.
The unused bits are undefined when reading the registers.
Fix/Workaround
Mask undefined bits when reading PRAS and PRBS.
10.2.12 TWIM
TWIM SR.IDLE goes high immediately when NAK is received
When a NAK is received and there is a non-zero number of bytes to be transmitted,
SR.IDLE goes high immediately and does not wait for the STOP condition to be sent. This
does not cause any problem just by itself, but can cause a problem if software waits for
SR.IDLE to go high and then immediately disables the TWIM by writing a one to CR.MDIS.
Disabling the TWIM causes the TWCK and TWD pins to go high immediately, so the STOP
condition will not be transmitted correctly.
Fix/Workaround
If possible, do not disable the TWIM. If it is absolutely necessary to disable the TWIM, there
must be a software delay of at least two TWCK periods between the detection of
SR.IDLE==1 and the disabling of the TWIM.
TWIM TWALM polarity is wrong
The TWALM signal in the TWIM is active high instead of active low.
Fix/Workaround
Use an external inverter to invert the signal going into the TWIM. When using both TWIM
and TWIS on the same pins, the TWALM cannot be used.