WELCOME to ARM7 TDMI -- LPC2378
The views below are of my own and readers are advised to follow datasheets/technical references for clarification/details.
I personally have worked upon with PIC18F4520,ATmega16 and 32 and P89v51RD2 microcontrollers ,over my academic career(till 3-2).
I took this semester(4-1) , a course on Embedded systems which introduced me to me to ARM and DSP architecture.
A quite major part f the course revolved around understanding the ARM architecture implementation in Philips LPC2378 microcontroller.
In the following I wish to give my view on how I felt LPC2378 different from what I already knew:
The views below are of my own and readers are advised to follow datasheets/technical references for clarification/details.
I personally have worked upon with PIC18F4520,ATmega16 and 32 and P89v51RD2 microcontrollers ,over my academic career(till 3-2).
I took this semester(4-1) , a course on Embedded systems which introduced me to me to ARM and DSP architecture.
A quite major part f the course revolved around understanding the ARM architecture implementation in Philips LPC2378 microcontroller.
In the following I wish to give my view on how I felt LPC2378 different from what I already knew:
1. ARM is a soft core processor : To explain it simply, what ARM does is develops processor architecture , say in the form of verilog code or other HDL.People can use this core and develop processors/microcontrollers/peripherals around it and come up with their own chip having ARM as their core processoor.LPC2378 too has ARM core and many peripheral support alongwith.
2. It is a 32 bit processor,unlike PIC and ATmega which where 8 bit ones,meaning that the working set of registers and the ALU input are of bus width of 32 bits.
As such my notion of 'n-bit processor' was that the databus width will be 32 bits,or the memory width is of 32 bits.Rather in LPC 2378 the memory itself is byte addressable only.The memory address are though of 32-bits.
3. Meaning of RISC processor :
RISC stands for Reduced instruction set code.
Now my earlier notion of it was RISC instruction set has lesser no. of instructions and that each instruction by itself performs a simple task and a combination of them needs to be executed to achieve a complex task(if necessary)
But I was wrong.RISC instructions can infact involved very complex logic implementation.What is "Reduced " as such in RISC is the overhead involved in decoding the instruction.i.e. RISC processor has a relatively simpler instruction decoding logic.
3. Instruction Set :
(a) ARM supports 2 sets of instruction mode : (1) Thumb mode (2)ARM mode.
2. It is a 32 bit processor,unlike PIC and ATmega which where 8 bit ones,meaning that the working set of registers and the ALU input are of bus width of 32 bits.
As such my notion of 'n-bit processor' was that the databus width will be 32 bits,or the memory width is of 32 bits.Rather in LPC 2378 the memory itself is byte addressable only.The memory address are though of 32-bits.
3. Meaning of RISC processor :
RISC stands for Reduced instruction set code.
Now my earlier notion of it was RISC instruction set has lesser no. of instructions and that each instruction by itself performs a simple task and a combination of them needs to be executed to achieve a complex task(if necessary)
But I was wrong.RISC instructions can infact involved very complex logic implementation.What is "Reduced " as such in RISC is the overhead involved in decoding the instruction.i.e. RISC processor has a relatively simpler instruction decoding logic.
3. Instruction Set :
(a) ARM supports 2 sets of instruction mode : (1) Thumb mode (2)ARM mode.