Datasheet

67
32059L–AVR32–01/2012
AT32UC3B
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
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.
- 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.