# Vault 7: Projects

This publication series is about specific projects related to the Vault 7 main publication.

### Protego

# PIC24FJ32MC10X -- Data Memory

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PIC24F Family Reference Manual
DS39717A-page 3-6 Advance Information © 2007 Microchip Technology Inc.
3.4 SOFTWARE STACK
For stack operations, some portion of the data memory of the PIC24F devices needs to be
allocated as stack. For additional details on software stack, refer to Section 2.3 “Software Stack
Pointer”.
3.5 INTERFACING PROGRAM AND DATA MEMORY SPACES
The PIC24F architecture uses a 24-bit wide program space and 16-bit wide data space. The
architecture is also a modified Harvard scheme, meaning that data can also be present in the
program space. To use this data successfully, it must be accessed in a way that preserves the
alignment of information in both spaces.
Aside from normal execution, the PIC24F architecture provides two methods by which program
space can be accessed during operation:
• Using table instructions to access individual bytes or words anywhere in the program space
• Remapping a portion of the program space into the data space (Program Space Visibility)
Table instructions allow an application to read or write to small areas of the program memory.
This makes the method ideal for accessing data tables that need to be updated from time to time.
It also allows access to all bytes of the program word. The remapping method allows an
application to access a large block of data on a read-only basis, which is ideal for look-ups from
a large table of static data. It can only access the least significant word of the program memory.
For additional details regarding the program and data memory interface, please refer to Section 4.3
“Data Access from Program Memory”.

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