![](http://datasheet.mmic.net.cn/100000/IF180C52TXXX-20R_datasheet_3493957/IF180C52TXXX-20R_812.png)
812
32099I–01/2012
AT32UC3L016/32/64
6.
TWIS stretch on Address match error
When the TWIS stretches TWCK due to a slave address match, it also holds TWD low for
the same duration if it is to be receiving data. When TWIS releases TWCK, it releases TWD
at the same time. This can cause a TWI timing violation.
Fix/Workaround
None.
35.1.10
PWMA
1.
BUSY bit is never cleared after writes to the Control Register (CR)
When writing a non-zero value to CR.TOP, CR.SPREAD, or CR.TCLR when the PWMA is
disabled (CR.EN == 0), the BUSY bit in the Status Register (SR.BUSY) will be set, but never
cleared.
Fix/Workaround
When writing a non-zero value to CR.TOP, CR.SPREAD, or CR.TCLR, make sure the
PWMA is enabled, or simultaneously enable the PWMA by writing a one to CR.EN.
2.
Incoming peripheral events are discarded during duty cycle register update
Incoming peripheral events to all applied channels will be discarded if a duty cycle update is
received from the user interface in the same PWMA clock period.
Fix/Workaround
Ensure that duty cycle writes from the user interface are not performed in a PWMA period
when an incoming peripheral event is expected.
35.1.11
ADCIFB
1.
Using STARTUPTIME larger than 0x1F will freeze the ADC
Writing a value larger than 0x1F to the Startup Time field in the ADC Configuration Register
(ACR.STARTUP) will freeze the ADC, and the Busy Status bit in the Status Register
(SR.BUSY) will never be cleared.
Fix/Workaround
Do not write values larger than 0x1F to ACR.STARTUP.
35.1.12
CAT
1.
CAT asynchronous wake will be delayed by one AST event period
If the CAT detects a condition the should asynchronously wake the device in static mode,
the asynchronous wake will not occur until the next AST event. For example, if the AST is
generating events to the CAT every 50ms, and the CAT detects a touch at t=9200ms, the
asynchronous wake will occur at t=9250ms.
Fix/Workaround
None.
2.
CAT QMatrix sense capacitors discharged prematurely
At the end of a QMatrix burst charging sequence that uses different burst count values for
different Y lines, the Y lines may be incorrectly grounded for up to n-1 periods of the periph-
eral bus clock, where n is the ratio of the PB clock frequency to the GCLK_CAT frequency.
This results in premature loss of charge from the sense capacitors and thus increased vari-
ability of the acquired count values.
Fix/Workaround
Enable the 1kOhm drive resistors on all implemented QMatrix Y lines (CSA 1, 3, 5, 7, 9, 11,
13, and/or 15) by writing ones to the corresponding odd bits of the CSARES register.
3.
CAT module does not terminate QTouch burst on detect