[En-Nut-Discussion] Harware SPI usage
harald.kipp at egnite.de
Mon Nov 12 11:24:36 CET 2007
Petri Hyötylä schrieb:
> I'm planning to use the MCU's hardware SPI in a project.
> Is there some precautions in using it to avoid collisions with
> Ethernut's internal SPI traffic or is the hardware SPI complete out of
You are free to use any hardware resource, except timer 0. You can use
native interrupts like with any non-Nut/OS application.
> My guess is that the time that I keep my /CS low has to be a nut
> critical section.
Definitely not. Nut/OS is a cooperative tasker. EnterCritical blocks
preemptive context switching. Only interrupts are preemptive with
Nut/OS, threads are not. As long as your thread is not blocked by I/O or
timer, the thread context will not switch.
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