A PPIB channel in one PPI system can be connected to a PPIB channel in another PPI system forming a PPIB connection.
A channel belonging to a PPIB instance in a PPI system is connected to a channel belonging to a PPIB instance in a different PPI system, creating a one-to-one PPIB connection between the two PPI systems. The connections are fixed and point-to-point, that is, a channel in a PPIB instance is connected only to a specific channel in another PPIB instance. For information on how the channels in the different PPIB instances are connected, see the Configuration table under the Registers section.
A PPIB channel can be configured as either source or sink. When configuring one side of the PPIB connection as source, the other side of the PPIB connection must be configured as sink, and viceversa. PPIB connections are unidirectional. Configuring both sides of a connection as source and sink at the same time will yield unexpected results.
On the source side of a PPIB connection, in order to send a (local) peripheral event to a different PPI system, the corresponding PPIB channel is configured as a consumer, subscribing to the same DPPI channel as the (local) peripheral publishes to, using the PPIB.SUBSCRIBE_SEND[n] register, with n the PPIB channel number.
On the sink side of a PPIB connection, for a (local) peripheral to be able to receive this event, the corresponding PPIB channel is configured as a producer, publishing to the same DPPI channel as the (local) peripheral subscribes to, using the PPIB.PUBLISH_RECEIVE[n] register, with n the PPIB channel number.
In a PPI system, several peripherals can publish to the same DPPI channel on the source side of a PPIB connection. Similarly, several peripherals can subscribe to the same DPPI channel on the sink side of a PPIB connection. This allows multiple connection options between peripherals in different PPI systems, same as DPPI allows in a local PPI system: one-to-one, one-to-many, many-to-one and many-to-many. However, when multiple peripherals can publish to the same DPPI channel on the source side of a PPIB connection, there is a risk of overflow. See Handshake and overflow.