Connection examples

DPPI offers several connection options. Examples are given for how to create one-to-one and many-to-many connections.

One-to-one connection

This example shows how to create a one-to-one connection between TIMER compare register and SAADC start task.

The channel configuration is set up first. TIMER0 will publish its COMPARE0 event on channel 0, and SAADC will subscribe its START task to events on the same channel. After that, the channel is enabled through the DPPIC.


NRF_TIMER0->PUBLISH_COMPARE0 = (DPPI_PUB_CHIDX_Ch0) | 
                               (DPPI_PUB_EN_Msk);
NRF_SAADC->SUBSCRIBE_START   = (DPPI_SUB_CHIDX_Ch0) | 
                               (DPPI_SUB_EN_Msk);
  
NRF_DPPIC->CHENSET = (DPPI_CHENSET_CH0_Set << DPPI_CHENSET_CH0_Pos);

Many-to-many connection

The example shows how to create a many-to-many connection, showcasing the DPPIC's channel group functionality.

A channel group that includes only channel 0 is set up first. Then the GPIOTE and TIMER0 configure their IN0 and COMPARE0 events respectively to be published on channel 0, while the SAADC configures its START task to subscribe to events on channel 0. Through DPPIC, the CHG0 DISABLE task is configured to subscribe to events on channel 0. After an event is received on channel 0 it will be disabled. Finally, channel 0 is enabled using the DPPIC task to enable a channel group.


NRF_DPPIC->CHG[0] = (DPPI_CHG_CH0_Included << PPI_CHG_CH0_Pos);
  
NRF_GPIOTE->PUBLISH_IN0         = (DPPI_PUB_CHIDX_Ch0) | 
                                  (DPPI_PUB_EN_Msk);
NRF_TIMER0->PUBLISH_COMPARE0    = (DPPI_PUB_CHIDX_Ch0) | 
                                  (DPPI_PUB_EN_Msk);
NRF_SAADC->SUBSCRIBE_START      = (DPPI_SUB_CHIDX_Ch0) | 
                                  (DPPI_SUB_EN_Msk);
NRF_DPPIC->SUBSCRIBE_CHG[0].DIS = (DPPI_SUB_CHIDX_Ch0) | 
                                  (DPPI_SUB_EN_Msk);

NRF_DPPIC->TASK_CHG[0].EN = 1;