Datasheet

86
AT32UC3A
15.5.4 USB
1. USB No end of host reset signaled upon disconnection
In host mode, in case of an unexpected device disconnection whereas a usb reset is being
sent by the usb controller, the UHCON.RESET bit may not been cleared by the hardware at
the end of the reset.
Fix/Workaround
A software workaround consists in testing (by polling or interrupt) the disconnection
(UHINT.DDISCI == 1) while waiting for the end of reset (UHCON.RESET == 0) to avoid
being stuck.
2. USBFSM and UHADDR1/2/3 registers are not available.
Do not use USBFSM register.
Fix/Workaround
Do not use USBFSM register and use HCON[6:0] field instead for all the pipes.
15.5.5 Processor and Architecture
1. Incorrect Processor ID
The processor ID reads 0x01 and not 0x02 as it should.
Fix/Workaround
None.
2. Bus error should be masked in Debug mode
If a bus error occurs during debug mode, the processor will not respond to debug com-
mands through the DINST register.
Fix/Workaround
A reset of the device will make the CPU respond to debug commands again.
3. Read Modify Write (RMW) instructions on data outside the internal RAM does not
work.
Read Modify Write (RMW) instructions on data outside the internal RAM does not work.
Fix/Workaround
Do not perform RMW instructions on data outside the internal RAM.
4. CRC calculation of a locked device will calculate CRC for 512 kB of flash memory,
even though the part has less flash.
Fix/Workaround
The flash address space is wrapping, so it is possible to use the CRC value by calculating
CRC of the flash content concatenated with itself N times. Where N is 512 kB/flash size.
5. Need two NOPs instruction after instructions masking interrupts
The instructions following in the pipeline the instruction masking the interrupt through SR
may behave abnormally.
Fix/Workaround
Place two NOPs instructions after each SSRF or MTSR instruction setting IxM or GM in SR.
32058KS–AVR32–01/12