[En-Nut-Discussion] interrupt sense control for RTL8019AS
hmlists at focus-sw.com
Tue Sep 19 04:43:53 CEST 2006
> It looks like a level triggered interrupt is replaced by an edge
> interrupt the moment the signal is inverted.
> Somebody knows what it should be, level or edge triggered sense control?
I probably can shed some light on this as I introduced the rising edge mode.
For a standard Ethernut hardware the classic level triggered mode should
be used. This mode is also backwards compatible to the Atmega103 MCU
which does not support edge triggered interrupts.
The polarity of the level triggered interrupt cannot be changed on the
ATmega128, but the polarity of an edge triggered interrupt can be
On our XNUT-100/XNUT-105 hardware design we use the rising edge
triggered mode for the RTL interrupt which saves use an inverter gate as
the RTL8019AS interrupt line (INT0) can be connected directly to the
ATmega128 input pin.
This mode is enabled in the driver by the macro definition
RTL_IRQ_RISING_EDGE and set in the Nut/OS configurator or in the .conf
As this works only for hardware designed for rising edge triggered mode,
it should not be used for a Ethernut 1.3 hardware.
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