Secure peripheral interconnect

An integrated-circuit device comprising:

• a bus system;
• a processor, connected to the bus system;
• a plurality of peripherals, each connected to the bus system;
• hardware filter logic;
• and
• a peripheral interconnect system, separate from the bus system and connected to the plurality of peripherals,
• wherein:
• for each of the plurality of peripherals, the hardware filter logic stores a respective value determining whether the peripheral is in a secure state;
• the peripheral interconnect system provides a set of one or more channels for signaling events between peripherals of the plurality of peripherals;
• at least one channel of the set of channels is a secure channel or is configurable to be a secure channel;
• the peripheral interconnect system is configured to allow an event signal from a peripheral that is in the secure state to be sent over a secure channel of the set of channels;
• and
• the peripheral interconnect system is configured to prevent an event signal from a peripheral that is not in the secure state from being sent over the secure channel;
• wherein the integrated-circuit device further comprises at least one of the following sets of features:
• A) the peripheral interconnect system provides a plurality of channels, wherein each channel that is not configured as a secure channel is a non-secure channel, and wherein at least one channel of the plurality of channels is a non-secure channel or is configurable to be a non-secure channel;
• B) the peripheral interconnect system is configured to allow event signals from secure peripherals and from non-secure peripherals to be sent over a non-secure channel of the set of channels;
• C) the peripheral interconnect system, or the hardware filter logic, provides a register interface for configuring channels of the set of channels as secure channels;
• D) the hardware filter logic comprises a system protection unit which provides a register interface for controlling whether one or more of the plurality of peripherals is in a secure state.