The AXI CDMA interrupt coalescing feature is enabled by
setting the CDMACR.IRQThreshold field to a value greater than the default value of 1. When a
SG session is started in the CDMA, the CDMACR.IRQThreshold field is loaded into the SG Engine
threshold counter. With each Interrupt On Complete event generated by the SG Engine (occurs
whenever the AXI CDMA completes a transfer descriptor), the threshold count is decremented.
When the count reaches zero, an IOC_Irq is generated by the SG Engine. If the
CDMACR.IOC_IrqEn = 1, an interrupt is generated on the AXI CDMA
cdma_introut signal.
If the delay interrupt feature is enabled (CDMACR.IRQDelay not equal to 0), a delay interrupt event causes a reload of the SG Engine interrupt threshold counter. In addition, a write by the software application to the threshold value (CDMACR.Threshold), the internal threshold counter is reloaded.