Low pin-count architecture with prioritized message arbitration and delivery

Methods and apparatus for implementing a low-pin count architecture with priority message arbitration and delivery. The architecture includes a hardware-based message arbitration unit (MAU) including a plurality of priority queues, each having a respective priority level, implemented on a first component, such as a processor and/or System on a Chip (SoC). The first component is communicatively coupled to a second component via a low-pin count link such as an I2C bus. The MAU receives prioritized messages from clients and enqueues the messages in priority queues based on their priority levels. An arbiter selects messages to transmit over the low-pin count link from the priority queues. The MAU further may abort transmission of a message in favor of transmission of a higher-priority message to guarantee a transmit latency. Under one implementation, the components are a processor and a PMIC configured to communicate with a USB Type-C power source and meet timing requirements defined by a USB Power Delivery Specification.