AT32UC3L064_11 ATMEL [ATMEL Corporation], AT32UC3L064_11 Datasheet - Page 81

• Manufacturer Part Number: AT32UC3L064_11
• Description: 32-bit Atmel AVR Microcontroller
• Manufacturer: ATMEL [ATMEL Corporation]

10.1.7
10.1.8
32099HS–12/2011
GPIO
SPI
2. WDT Control Register does not have synchronization feedback
1. Clearing GPIO interrupt may fail
1. SPI data transfer hangs with CSR0.CSAAT==1 and MR.MODFDIS==0
2. Disabling SPI has no effect on the SR.TDRE bit
3. SPI disable does not work in SLAVE mode
4. SPI bad serial clock generation on 2nd chip_select when SCBR=1, CPOL=1, and
Use twice as long timeout period as needed and clear the WDT counter within the first half
of the timeout period. If the WDT counter is cleared after the first half of the timeout period,
you will get a Watchdog reset immediately. If the WDT counter is not cleared at all, the time
before the reset will be twice as long as needed.
When writing to the Timeout Prescale Select (PSEL), Time Ban Prescale Select (TBAN),
Enable (EN), or WDT Mode (MODE) fieldss of the WDT Control Register (CTRL), a synchro-
nizer is started to propagate the values to the WDT clcok domain. This synchronization
takes a finite amount of time, but only the status of the synchronization of the EN bit is
reflected back to the user. Writing to the synchronized fields during synchronization can lead
to undefined behavior.
Fix/Workaround
-When writing to the affected fields, the user must ensure a wait corresponding to 2 clock
cycles of both the WDT peripheral bus clock and the selected WDT clock source.
-When doing writes that changes the EN bit, the EN bit can be read back until it reflects the
written value.
Writing a one to the GPIO.IFRC register to clear an interrupt will be ignored if interrupt is
enabled for the corresponding port.
Fix/Workaround
Disable the interrupt, clear it by writing a one to GPIO.IFRC, then enable the interrupt.
When CSR0.CSAAT==1 and mode fault detection is enabled (MR.MODFDIS==0), the SPI
module will not start a data transfer.
Fix/Workaround
Disable mode fault detection by writing a one to MR.MODFDIS.
Disabling SPI has no effect on the SR.TDRE bit whereas the write data command is filtered
when SPI is disabled. Writing to TDR when SPI is disabled will not clear SR.TDRE. If SPI is
disabled during a PDCA transfer, the PDCA will continue to write data to TDR until its buffer
is empty, and this data will be lost.
Fix/Workaround
Disable the PDCA, add two NOPs, and disable the SPI. To continue the transfer, enable the
SPI and PDCA.
SPI disable does not work in SLAVE mode.
Fix/Workaround
Read the last received data, then perform a software reset by writing a one to the Software
Reset bit in the Control Register (CR.SWRST).
NCPHA=0
When multiple chip selects (CS) are in use, if one of the baudrates equal 1 while one
(CSRn.SCBR=1) of the others do not equal 1, and CSRn.CPOL=1 and CSRn.NCPHA=0,
then an additional pulse will be generated on SCK.
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