Datasheet

79
32059L–AVR32–01/2012
AT32UC3B
even if the frame is correct and the USART has been disabled, reset by a soft reset and re-
enabled.
Fix/Workaround
None.
9. USART slave synchronous mode external clock must be at least 9 times lower in fre-
quency than CLK_USART
When the USART is operating in slave synchronous mode with an external clock, the fre-
quency of the signal provided on CLK must be at least 9 times lower than CLK_USART.
Fix/Workaround
When the USART is operating in slave synchronous mode with an external clock, provide a
signal on CLK that has a frequency at least 9 times lower than CLK_USART.
10. HMATRIX
11. 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.
- FLASHC
1. Reading from on-chip flash may fail after a flash fuse write operation (FLASHC LP,
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.
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.
- DSP Operations
1. Hardware breakpoints may corrupt MAC results
Hardware breakpoints on MAC instructions may corrupt the destination register of the MAC
instruction.
Fix/Workaround
Place breakpoints on earlier or later instructions.