SLAU847D October 2022 – May 2024 MSPM0L1105 , MSPM0L1106 , MSPM0L1227 , MSPM0L1228 , MSPM0L1228-Q1 , MSPM0L1303 , MSPM0L1304 , MSPM0L1304-Q1 , MSPM0L1305 , MSPM0L1305-Q1 , MSPM0L1306 , MSPM0L1306-Q1 , MSPM0L1343 , MSPM0L1344 , MSPM0L1345 , MSPM0L1346 , MSPM0L2227 , MSPM0L2228 , MSPM0L2228-Q1
Peripheral interrupt requests (IRQs) are propagated to the CPU subsystem through the event manager. Peripheral interrupt requests use fixed routes, but in addition the CPU subsystem may provide two generic event subscriber ports which can be used to trigger CPU interrupts through a generic route. See the device-specific data sheet for the complete list of interrupt assignments for a given device.
The CPU subsystem contains two generic event subscriber ports (FSUB_x) which can be used to source a CPU interrupt from any of the device's generic event channels. This can be used to enable special cases where a particular function on a peripheral generates a dedicated interrupt to the CPU subsystem which is independent from, and in addition to, that peripheral's standard interrupt mechanism.
Consider the GPIO peripheral, which has a standard interrupt request as well as 2 publishers which can route a GPIO event to any of the generic event channels based on a defined state in the GPIO. For example, it can be desirable to have most GPIO events configured to source the standard interrupt, while a single specific GPIO event sources a second dedicated CPU interrupt through a generic route. This enables the application software to have two completely independent interrupt handlers for the GPIO.
To configure the event manager to trigger a CPU interrupt from a generic route, follow the steps below:
Note that when generating a CPU interrupt through a generic route, the generic event logic will automatically clear the pending interrupt request as a part of the four-way event handshake. Application software will not be able to read the cause of the interrupt from the peripheral registers, and it does not need to clear any interrupt status bits. Software can only read that the FSUB_x generic event generated an interrupt. This reduces the interrupt overhead.