9.9.5 __pmp__ Type Qualifier
This qualifier may be used with those devices that contain a Parallel
Master Port (PMP) peripheral, which allows the connection of various memory and non-memory
devices directly to the device. When variables or pointer targets qualified with
__pmp__
are accessed, the compiler will generate the appropriate
sequence for accessing these objects via the PMP peripheral on the device. For example:
__pmp__ int auxDevice
__attribute__((space(pmp(external_PMP_memory))));
__pmp__ char * myPMPpointer;
In addition to the qualifier, the int
variable uses a
memory space which would need to be predefined. The pointer in this example does not use
the space
attribute as the it is located in data memory, but the qualifier
indicates how the pointer targets are to be accessed. For more information on the
space
attribute, see the 9.10 Variable Attributes section. For basic
information on the memory layout and how program memory is accessed by the device, see the
11.1 Address Spaces section.
For more on the qualifier, see the 11.4 Parallel Master Port Access section.