Atmel SAM4L Xplained Pro Evaluation Kit Atmel ATSAM4L-XPRO ATSAM4L-XPRO Data Sheet
Product codes
ATSAM4L-XPRO
167
42023ES–SAM–07/2013
ATSAM4L8/L4/L2
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).
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).
Disabling SPI has no effect on the SR.TDRE bit
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.
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 bad serial clock generation on 2nd chip_select when SCBR=1, CPOL=1, and
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.
Fix/Workaround
When multiple CS are in use, if one of the baudrates equals 1, the others must also equal 1
if CSRn.CPOL=1 and CSRn.NCPHA=0.
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.
Fix/Workaround
When multiple CS are in use, if one of the baudrates equals 1, the others must also equal 1
if CSRn.CPOL=1 and CSRn.NCPHA=0.
12.1.5
TC
Channel chaining skips first pulse for upper channel
When chaining two channels using the Block Mode Register, the first pulse of the clock
between the channels is skipped.
Fix/Workaround
Configure the lower channel with RA = 0x1 and RC = 0x2 to produce a dummy clock cycle
for the upper channel. After the dummy cycle has been generated, indicated by the
SR.CPCS bit, reconfigure the RA and RC registers for the lower channel with the real
values.
When chaining two channels using the Block Mode Register, the first pulse of the clock
between the channels is skipped.
Fix/Workaround
Configure the lower channel with RA = 0x1 and RC = 0x2 to produce a dummy clock cycle
for the upper channel. After the dummy cycle has been generated, indicated by the
SR.CPCS bit, reconfigure the RA and RC registers for the lower channel with the real
values.
12.1.6
USBC
In USB host mode, entering suspend mode for low speed device can fail when the
USB freeze (USBCON.FRZCLK=1) is done just after UHCON.SOFE=0.
Fix/Workaround
When entering suspend mode (UHCON.SOFE is cleared), check that USBFSM.DRDSTATE
is not equal to three before freezing the clock (USBCON.FRZCLK=1).
USB freeze (USBCON.FRZCLK=1) is done just after UHCON.SOFE=0.
Fix/Workaround
When entering suspend mode (UHCON.SOFE is cleared), check that USBFSM.DRDSTATE
is not equal to three before freezing the clock (USBCON.FRZCLK=1).
In USB host mode, the asynchronous attach detection (UDINT.HWUPI) can fail when
the USB clock freeze (USBCON.FRZCLK=1) is done just after setting the USB-
STA.VBUSRQ bit.
Fix/Workaround
A f t e r s e t t i n g U S B S T A . V B U S R Q b i t , w a i t u n t i l t h e U S B F S M r e g i s t e r v a l u e i s
‘A_WAIT_BCON’ before setting the USBCON.FRZCLK bit.
the USB clock freeze (USBCON.FRZCLK=1) is done just after setting the USB-
STA.VBUSRQ bit.
Fix/Workaround
A f t e r s e t t i n g U S B S T A . V B U S R Q b i t , w a i t u n t i l t h e U S B F S M r e g i s t e r v a l u e i s
‘A_WAIT_BCON’ before setting the USBCON.FRZCLK bit.