11.5 AHB-APB Bridge

The AHB-APB bridge is an AHB client, providing an interface between the high-speed AHB domain and the low-power APB domain. It is used to provide access to the Programmable Control registers of peripherals.

AHB-APB bridge is based on AMBA APB Protocol Specification V2.0 (ref. as APB4) including:
  • Wait state support
  • Error reporting
  • Transaction protection
  • Sparse data transfer (byte, half-word and word)
Additional enhancements:
  • Address and data cycles merged into a single cycle
  • Sparse data transfer also apply to read access
To operate the AHB-APB bridge, the clock (CLK_HPBx_AHB) must be enabled. See PM – Power Manager for details.
Figure 11-1. APB Write Access
Figure 11-2. APB Read Access