77
32099DS–06/2010
AT32UC3L016/32/64
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).
2.
SPI Bad Serial Clock Generation on 2nd chip select when SCBR==1, CPOL==1, and
NCPHA==0
W h e n m u l t i p l e c h i p s e l e c t s a r e i n u s e , i f o n e o f t h e b a u d r a t e s i s e q u a l t o 1
(CSRn.SCBR==1) and one of the others is not equal to 1, and CSRn.CPOL==1 and
CSRn.NCPHA==0, an additional pulse will be generated on SCK.
Fix/Workaround
When multiple chip selects are in use, if one of the baudrates is equal to 1, the others must
also be equal to 1 if CSRn.CPOL==1 and CSRn.NCPHA==0.
3.
SPI data transfer hangs with CSR0.CSAAT==1 and MR.MODFDIS==0
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.
4.
Disabling SPI has no effect on the SR.TDRE bit
Disabling SPI has no effect on SR.TDRE whereas the write data command is filtered when
SPI is disabled. This means that as soon as the SPI is disabled it becomes impossible to
reset the SR.TDRE bit by writing to TDR. So if the SPI is disabled during a PDCA transfer,
the PDCA will continue to write data to TDR (as SR.TDRE stays high) until its buffer is
empty, and all data written after the disable command is lost.
Fix/Workaround
Disable the PDCA, add 2 NOP (minimum), and disable the SPI. To continue the transfer,
enable the SPI and the PDCA.
6.
SPI mode fault detection enable causes incorrect behavior
When mode fault detection is enabled (MR.MODFDIS==0), the SPI module may not operate
properly.
Fix/Workaround
Always disable mode fault detection before using the SPI by writing a one to MR.MODFDIS.
10.4.14
TWI
1.
TWIM Version Register reads zero
TWIM Version Register (VR) reads zero instead of 0x101.
Fix/Workaround
None.
2.
TWIS Version Register reads zero
TWIS Version Register (VR) reads zero instead of 0x112.
Fix/Workaround
None.
3.
TWIS CR.STREN does not work in deep sleep modes
When the device is in Stop, DeepStop, or Static mode, address reception will not wake the
device if both CR.SOAM and CR.STREN are one.
Fix/Workaround
Do not write both CR.STREN and CR.SOAM to one if the device needs to wake from deep
sleep modes.
4.
TWI pins are not SMBus compliant