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LPC2917_19_1
© NXP B.V. 2007. All rights reserved.
Preliminary data sheet
Rev. 1.01 — 15 November 2007
2 of 68
NXP Semiconductors
LPC2917/19
ARM9 microcontroller with CAN and LIN
2.2 ARM968E-S processor
The ARM968E-S is a general purpose 32-bit RISC processor, which offers high
performance and very low power consumption. The ARM architecture is based on
Reduced Instruction Set Computer (RISC) principles, and the instruction set and related
decode mechanism are much simpler than those of micro-programmed Complex
Instruction Set Computers (CISC). This simplicity results in a high instruction throughput
and impressive real-time interrupt response from a small and cost-effective controller
core.
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 x 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
Ref. 2
.
2.3 On-chip flash memory system
The LPC2917/19 includes a 512 kB or 768 kB flash memory system. This memory can be
used for both code and data storage. Programming of the flash memory can be
accomplished in several ways. It may be programmed in-system via a serial port; e.g.
CAN.