3 APB ROM table

The css600_apbrom module is a ROM Table with an APB4 slave interface.

The css600_apbrom_gpr is a ROM Table that includes the Granular Power Requestor (GPR) function.

Use the css600_apbrom or css600_apbrom_gpr to:

  • Identify part of your system or subsystem.
  • Indicate the locations of other CoreSight™ components in the same address space to an External Debugger.
  • Request power or reset to be supplied to components in the debug subsystem or the wider system (css600_apbrom_gpr only).

The css600_apbrom and css600_apbrom_gpr support up to 511 32-bit component entries, which are set by configuration parameters. The css600_apbrom and css600_apbrom_gpr support dynamic control of the ROM Table IDs and, optionally the presence of each entry, using configuration input signals. These features make the ROM Table suitable for use in configurable and hardened subsystems.

The css600_apbrom_gpr version adds the capability to request power or reset to individual components or parts of a system through a power or reset controller that is implemented outside the CoreSight subsystem. Power request interface numbers are normally aligned to power domain IDs configured into the ROM Table.

The GPR configuration provides the following additional features:

  • Authentication interface to control access to power and reset control features.
  • Configurable number, up to 32, of debug power request interfaces, comprising a cdbgpwrupreq and cdbgpwrupack pair of signals.
  • Configurable number, up to 32, of system power request interfaces, comprising a csyspwrupreq and csyspwrupack pair of signals.
  • A debug reset request interface, comprising a cdbgrstreq and cdbgrstack pair of signals.
  • A system reset request interface, comprising a csysrstreq and csysrstack pair of signals.

The following figure shows the external connections on the APB ROM table.

Figure 3-2 css600_apbrom logical connections
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The following figure shows the external connections on the APB ROM table with GPR.

Figure 3-3 css600_apbrom_gpr logical connections
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