NEED advice on ARM7 or PIC32MX

[3BABY]

Hi all,

im trying to decide weather to go with an ARM microcontroller or a Microchip PIC32MX series microcontroller for the "heart" of my project, basically all it will be doing is crunching numbers. running between 32-as fast as i can go MHz

ive done allot of reading around the web but i can seem to find a free compiler that i can write code in assembly for an ARM

im used to MPLAB and the 8bit PIC uC's but need something 32bit capable & im leaning towards ARM.. but i guess its compiler dependant.


any advice on Development environments for either would be appreciated..

 

[wp100]

Hi,

Most high end micros like those are really designed for C etc.

Assembler may be possible, but rather more complicated than the 16Fs; not easy and not well spported in any forum I have seen.

Perhaps give more detail of what you are tryig to do, and someone may be able to suggest the best route; a fast Pic18 chip might do just as well and is 16F assembler compatible.

 

[Easyrider83]

If you really planing to use assembler for 32 bit cores, better choose PIC32 family. It will be much easier to learn. But I think it will be a very hard work. Can't understand you. Most of all programmers in a world using C.

 

[3BABY]

Hi,

Most high end micros like those are really designed for C etc.

Assembler may be possible, but rather more complicated than the 16Fs; not easy and not well spported in any forum I have seen.

Perhaps give more detail of what you are tryig to do, and someone may be able to suggest the best route; a fast Pic18 chip might do just as well and is 16F assembler compatible.

If you really planing to use assembler for 32 bit cores, better choose PIC32 family. It will be much easier to learn. But I think it will be a very hard work. Can't understand you. Most of all programmers in a world using C.

thanks Guys,

well it looks like i may just have to use a C compiler.. it isnt really an issue.. i just prefer assembly but yes i think your right.. assembly would get very complicated with 32bits. im needing the uC for some mathematical compuations, some decimal to BCD and vise vera conversions and a couple big tables.. it also needs to receive allot data over 3-4 separate 8 bit buss's and really needs to happen in less than 4mS .. wats your opinions guys.. ARM or PIC32? ARM is widely used these days thats why i was leaning toward it is all, it would be useful to know the architecture.

 

[wp100]

Hi,

First have a look at the Pic18 assembler instruction set, there are a few extra ones that help with maths routines.

Most 18F chips will do 10 mips while the 18Js will do 16 mips, many with 50+ i/o lines, though smd.
Still it would be easy enough to add some 74244/245 octal buffers if you wanted to use a smaller dil chip of 40 or less pins

Things like bcd to decimal are quick and easy routines, as are lookup tables, I use one with 255 values, do you need more ?
See PicList.com for ready made assembler maths amd conversion routines.

Needs to happen within 4ms - why ?

 

[poorchava]

PIC32 (which is basically MIPS4k core + PIC24H peripherals) is nice, but there isn't much support for it. On the other hand you get a core which can be overclocked up to 120 MHz (from nominal 80 MHz) with theoretical limit of 1.56 MIPS/MHz.

As for ARM I'd ditch the ARM7 core. There are many faster cores now. For example LPC4300 series are assymetrical dual core microcontrollers. Main core is Cortex-M4 and coprocessor is Cortex-M0. Other nice option are STM32 F4 series MCU's. Some of them also have dsp core.

 

[3BABY]

Hi,

First have a look at the Pic18 assembler instruction set, there are a few extra ones that help with maths routines.

Most 18F chips will do 10 mips while the 18Js will do 16 mips, many with 50+ i/o lines, though smd.
Still it would be easy enough to add some 74244/245 octal buffers if you wanted to use a smaller dil chip of 40 or less pins

Things like bcd to decimal are quick and easy routines, as are lookup tables, I use one with 255 values, do you need more ?
See PicList.com for ready made assembler maths amd conversion routines.

Needs to happen within 4ms - why ?

the unit will be working in a machine that had some other 8bit uC connected to it via the buss's i was talking about and these pass it new information at minimum every 4mS.

PIC32 (which is basically MIPS4k core + PIC24H peripherals) is nice, but there isn't much support for it. On the other hand you get a core which can be overclocked up to 120 MHz (from nominal 80 MHz) with theoretical limit of 1.56 MIPS/MHz.

As for ARM I'd ditch the ARM7 core. There are many faster cores now. For example LPC4300 series are assymetrical dual core microcontrollers. Main core is Cortex-M4 and coprocessor is Cortex-M0. Other nice option are STM32 F4 series MCU's. Some of them also have dsp core.

PIC32 looks very nice. but then again so do the dual core ARM's , im now thinking in terms of a suitable development board. i cant see any for the LPC4300 that are full featured that dont cost less then $250 USD.. (thats about the budget)

another thing as wp100 mentioned is that i will have to use buffers to interface the 16F and 18F uC's i have doing the dummy work for the bidirectional data/address buss. its a pitty companies dont build these into boards but i guess it would take up too much room and these so many voltage levels these days..

 

[wp100]

Hi,

Sounds like you are trying to bleed data directly off the data bus of a PC ?

You really need to be more specific in your details to get qualified answers.

Even a Pic18 running on its internal osc can do 16,000 instruction in 4ms, with an external osc up to 64,000 instructions.

So what kind of computing are you wanting to do with that data in 4ms and where will the results go, unless its back to the PC what can use or store that amount of data ?