To avoid the accumulation of conversion error, the count in timer driver
should use the same time unit as the hardware. BTW, your timer driver
has
to implement the up_alarm_xxx functions.
Unfortunately, 32.768KHz is a very common clock frequency and it
cannot be handled by the current lo
To avoid the accumulation of conversion error, the count in timer driver
should use the same time unit as the hardware. BTW, your timer driver has
to implement the up_alarm_xxx functions.
Unfortunately, 32.768KHz is a very common clock frequency and it cannot
be handled by the current logic.
Hi Greg,
thanks for your advices.
> If you use 32.768KHz clock source, then there is a small error in every
> time conversion since 1/32768 cannot be represented in microseconds.
> Normally, this will result in small errors as you have noted. However,
> in a very busy system with man t
To avoid the accumulation of conversion error, the count in timer driver
should use the same time unit as the hardware. BTW, your timer driver has
to implement the up_alarm_xxx functions.
On Sun, Jul 11, 2021 at 9:10 AM Gregory Nutt wrote:
> Actually, the situation is much worse:
>
> https://git
Actually, the situation is much worse:
https://github.com/apache/incubator-nuttx/blob/master/boards/arm/sama5/sama5d3x-ek/README.txt#L2823
If you use 32.768KHz clock source, then there is a small error in every
time conversion since 1/32768 cannot be represented in microseconds.
Normally, thi
Hi Alan,
Thanks for the suggestion - I have GDB and J-Link and am using VS Code
as my IDE, which does have some "watch" limitations it seems :(
But I have found I was wrong about it being NuttX that's changing the
SFR register. It seems that U-boot doesn't set it despite being
configured for
The other source of the inaccuracy can be in clock frequency. I use 32 kHz
clock source, but this value cannot be properly represented by CONFIG_USEC_
PER_TICK, which I set to 31 (which is aproximately 32.25 kHz). But 32 kHz
clock source seems to be the only possible in iMXRT as others are to h
Hi Alan,
thanks for the link! I will take a look into it.
Best regards,
Michal Lenc
-- Původní e-mail --
Od: Alan Carvalho de Assis
Komu: dev@nuttx.apache.org
Datum: 11. 7. 2021 16:19:59
Předmět: Re: Tickless mode for iMXRT MCU
"Hi Michal,
Please take a look at this wiki p
Hi Michal,
Please take a look at this wiki page, it could help you to understand
the issue with sleep take one more context switch cycle:
https://cwiki.apache.org/confluence/display/NUTTX/Short+Time+Delays
Unfortunately the Timer Hook that could help you in this case will not
work in Tickless mod
Hello,
I´ve finished the implementation of tickless mode support for iMXRT MCU,
which is a part of my Google Summor of Code project (https://cwiki.apache.
org/confluence/display/NUTTX/%5B2021%5D+NuttX+Support+for+Rapid+Control+
Applications+Development+with+pysimCoder). The source code can be
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