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UM10316_0
© NXP B.V. 2008. All rights reserved.
User manual
Rev. 00.06 — 17 December 2008
14 of 571
NXP Semiconductors
UM10316
Chapter 1: LPC29xx Introductory information
Amongst the most compelling features of the ARM968E-S are:
•
Separate directly connected instruction and data Tightly Coupled Memory (TCM)
interfaces
•
Write buffers for the AHB and TCM buses
•
Enhanced 16
×
32 multiplier capable of single-cycle MAC operations and 16-bit fixed-
point DSP instructions to accelerate signal-processing algorithms and applications.
Pipeline techniques are employed so that all parts of the processing and memory systems
can operate continuously. The ARM968E-S is based on the ARMv5TE five-stage pipeline
architecture. Typically, in a three-stage pipeline architecture, while one instruction is being
executed its successor is being decoded and a third instruction is being fetched from
memory. In the five-stage pipeline additional stages are added for memory access and
write-back cycles.
The ARM968E-S processor also employs a unique architectural strategy known as
THUMB, which makes it ideally suited to high-volume applications with memory
restrictions or to applications where code density is an issue.
The key idea behind THUMB is that of a super-reduced instruction set. Essentially, the
ARM968E-S processor has two instruction sets:
•
Standard 32-bit ARMv5TE set
•
16-bit THUMB set
The THUMB set's 16-bit instruction length allows it to approach twice the density of
standard ARM code while retaining most of the ARM's performance advantage over a
traditional 16-bit controller using 16-bit registers. This is possible because THUMB code
operates on the same 32-bit register set as ARM code.
THUMB code can provide up to 65 % of the code size of ARM, and 160 % of the
performance of an equivalent ARM controller connected to a 16-bit memory system.
The ARM968E-S processor is described in detail in the ARM968E-S data sheet.
9.
On-chip flash memory system
The LPC29xx includes up to 768 kB flash memory system. This memory can be used for
both code and data storage. Flash memory can be programmed in-system via a serial port
(e.g., CAN).
10. On-chip static RAM
In addition to the two 16 kB or 32 kB TCMs, the LPC29xx includes two static RAM
memories: one of up to 32 kB and one of 16 kB. Both may be used for code and/or data
storage.