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Discussion Groups | AT91SAM ARM | Help needed in AT91SAM9263 CPU Rev.A SPI/PDC issue
For users of the Atmel AT91SAM7 and AT91SAM9 ARM CPU chips. Atmel has taken a new direction by combining on chip flash and ram with the ARM CPU on a single die. This provides low cost devices for small systems using the ARM CPU. This group is to exchange information to help users get started and learn how to use the devices.
Help needed in AT91SAM9263 CPU Rev.A SPI/PDC issue - alipowsky - May 2 10:08:17 2008
We have a SPI coupled ADC and DAC on SPI0 Bus of the cpu.
We read start a PDC transfer every 50 us to write the DAC and read the
ADC values.
We now encounter problems with reading the ADC values in that
way, that the data read by the PDC, seems not to be written to the
location, which was given in the appropriate PDC pointer register,
resulting into zero values read from the ADC.
This happens sporadic, sometimes after 10-15 minutes of system
operation, sometimes within 1-2 minutes.
Til now we could not find a correlation to a specific context of the
cpu, which might cause this behaviour.
Is there anybody out there, who also encountered this problem, and who
might have found any workaround.
The problems does not appear, with our sample board, which carries a
Rev.B cpu, but unfortunately this cpu's are not yet available now, and
we need to deliver our first products immediately.
regards
Andreas
------------------------------------
(You need to be a member of AT91SAM -- send a blank email to AT91SAM-subscribe@yahoogroups.com )
We read start a PDC transfer every 50 us to write the DAC and read the
ADC values.
We now encounter problems with reading the ADC values in that
way, that the data read by the PDC, seems not to be written to the
location, which was given in the appropriate PDC pointer register,
resulting into zero values read from the ADC.
This happens sporadic, sometimes after 10-15 minutes of system
operation, sometimes within 1-2 minutes.
Til now we could not find a correlation to a specific context of the
cpu, which might cause this behaviour.
Is there anybody out there, who also encountered this problem, and who
might have found any workaround.
The problems does not appear, with our sample board, which carries a
Rev.B cpu, but unfortunately this cpu's are not yet available now, and
we need to deliver our first products immediately.
regards
Andreas
------------------------------------
(You need to be a member of AT91SAM -- send a blank email to AT91SAM-subscribe@yahoogroups.com )