1.3.2.2
Flash Memory (see page 604)
The TM4C1294NCPDT microcontroller provides 1024 KB of on-chip Flash memory. The Flash
memory is configured as four banks of 16K x 128 bits (4 * 256 KB total) which are two-way
interleaved. Memory blocks can be marked as read-only or execute-only, providing different levels
of code protection. Read-only blocks cannot be erased or programmed, protecting the contents of
those blocks from being modified. Execute-only blocks cannot be erased or programmed, and can
only be read by the controller instruction fetch mechanism, protecting the contents of those blocks
from being read by either the controller or by a debugger.
The TM4C1294NCPDT microcontroller provides enhanced performance and power savings by
implementation of two sets of instruction prefetch buffers. Each prefetch buffer is 2 x 256 bits and
can be combined as a 4 x 256-bit prefetch buffer.
The Flash can also be accessed by the µDMA in Run Mode.
1.3.2.3
ROM (see page 602)
The TM4C1294NCPDT ROM is preprogrammed with the following software and programs:
■ TivaWare Peripheral Driver Library
■ TivaWare Boot Loader
■ Advanced Encryption Standard (AES) cryptography tables
■ Cyclic Redundancy Check (CRC) error-detection functionality
The TivaWare Peripheral Driver Library is a royalty-free software library for controlling on-chip
peripherals with a boot-loader capability. The library performs both peripheral initialization and
control functions, with a choice of polled or interrupt-driven peripheral support. In addition, the library
is designed to take full advantage of the stellar interrupt performance of the ARM Cortex-M4F core.
No special pragmas or custom assembly code prologue/epilogue functions are required. For
applications that require in-field programmability, the royalty-free TivaWare Boot Loader can act as
an application loader and support in-field firmware updates.
The Advanced Encryption Standard (AES) is a publicly defined encryption standard used by the
U.S. Government. AES is a strong encryption method with reasonable performance and size. In
addition, it is fast in both hardware and software, is fairly easy to implement, and requires little
memory. The Texas Instruments encryption package is available with full source code, and is based
on Lesser General Public License (LGPL) source. An LGPL means that the code can be used within
an application without any copyleft implications for the application (the code does not automatically
become open source). Modifications to the package source, however, must be open source.
CRC (Cyclic Redundancy Check) is a technique to validate a span of data has the same contents
as when previously checked. This technique can be used to validate correct receipt of messages
(nothing lost or modified in transit), to validate data after decompression, to validate that Flash
memory contents have not been changed, and for other cases where the data needs to be validated.
A CRC is preferred over a simple checksum (for example, XOR all bits) because it catches changes
more readily.
Note:
CRC software program are available in the TivaWare™ for C Series software for
backward-compatibility. A device that has enhanced CRC integrated module should utilize
this hardware for best performance. Please refer to “Cyclical Redundancy Check
(CRC)” on page 946 for more information.
June 18, 2014
58
Texas Instruments-Production Data
Architectural Overview