APB (Advanced Peripheral Bus) Master
The APB Master, a key component in the AMBA-APB architecture, plays a vital role in managing data transfers between the high-level system bus and the APB slave devices. Here’s an overview of the functions and operations of the APB Master
Role and Configuration: In Figure 1, both the APB Master and APB slave are depicted as block diagrams. In the context of AMBA-APB, the APB bridge serves as a bus master. Additionally, it operates as a slave when connected to the high-level system shuttle.
Data Transfer Control: The primary function of the APB Bridge is to facilitate the transfer of data and addresses from the high-level System bus to the APB. It accomplishes this task through a series of coordinated actions:
- Latching Addresses: The APB Bridge latches the address and maintains its accuracy throughout the entire data transfer process. This ensures that the correct memory location or peripheral device is accessed.
- Address Decoding: The latched address is then decoded by the APB Bridge. This decoding process results in the creation of a peripheral pick signal denoted as PSELx. Importantly, only one select signal can be active at any given time, which prevents conflicts during data transfers.
- Data Write Operations: To write data to the APB, the APB Bridge employs a specific method that ensures accurate and reliable data transmission. This method is essential for updating registers and memory locations in the connected peripherals.
- Data Read Operations: Conversely, when reading data from the APB, the APB Bridge handles the transfer in such a way that APB data is efficiently conveyed to the high-level System bus. This mechanism guarantees that the requested data is made available for processing and usage.
In summary, the APB Master’s pivotal role within the AMBA-APB architecture involves controlling data transfers between the high-level System bus and the APB-connected slave devices. It accomplishes this by latching, decoding, and managing addresses, as well as facilitating both write and read operations with precision and reliability. This coordination is vital for the seamless functioning of the overall system.