Angel requires the following configurable and non-configurable resources:

Angel requires ROM or Flash memory to store the debug monitor code, and RAM to store data. The amount of ROM, Flash, and RAM required varies depending on your configuration.

Additional RAM is required to download a new version of Angel:

Angel requires some control over the ARM exception vectors. Exception vectors are initialized by Angel, and are not written to after initialization. This supports systems with ROM at address 0, where the vectors cannot be overwritten.

Angel installs itself by initializing the vector table so that it takes control of the target when an exception occurs. For example, debug communications from the host cause an interrupt that halts the application and calls the appropriate code within Angel.

Angel requires use of at least one interrupt to support communication between the host and target systems. You can set up Angel to use:

It is recommended that you use FIQ for your own interrupt requirements because Angel has no fast interrupt requirements. Refer to devconf.h for more information.

Angel requires control over its own Supervisor stack. If you want to make Angel calls from your application you must set up your own stacks. Refer to Developing an application under full Angel for more information.

Angel also requires that the current stack pointer points to a few words of usable full descending stack whenever an exception is possible, because the Angel exception return code uses the application stack to return.