8-bit MicrocontrollersのトピックRe: newbie questions

newbie questions - MC9S08JM60

gbaars — Sat, 28 Jun 2008 17:44:05 GMT

For the DEMOJM Codewarrior has been installed.

I can place MC9S08JM60 and MCF51JM128 controllers.

I'am experienced with AVR and AVRStudio in assembler

and want to start exploring this matter starting with the

MC9S08JM in asm.

Few questions:

-Does the Codewarrior IDE contain help on the controllers

instructions sets and registers?

-Is the HC08 architecture/registers/instructionset generally the same

as for the MC9S08JM60.

-What MIPS/MHZ is possible?

-Can the DEMOJM board be used for in circuit programming

of other HC08 based controllers?

Added p/n to subject.

Message Edited by NLFSJ on 2008-06-30 02:30 PM

Re: newbie questions

JimDon — Sat, 28 Jun 2008 21:35:11 GMT

- The instruction set and reference for the MCU and generally contained in the Reference Manual (RM) for the chip. There is also the HCS08RMV1 for HCS08 and the CFPRM for the Coldfire. However you should start with the RM for the MCU as new instructions will be there rather than in the base manual.
The RMs can be found on the web page for the chip.

Having said that, I strongly recommend you use "C". It is one thing to become familiar with the instruction set, but if you use asm, your code will not move between the freescale families at all.

You can use the DEMOJM to program/debug other boards. You will need to install the 6 pin header and get a 6 pin flat cable.

Re: newbie questions

gbaars — Sat, 28 Jun 2008 21:49:45 GMT

Thanks for reply. I find the CFPRM usefull.

I want to use a MCF51 device for the better

MIPS. I see the MC9SO8 devices have

high average on inst/cycle resulting in low

MIPS/Mhz.

Since speed optimizing is prior for my application

maybe C is not the best choice?

What MIPS do you think is maximum for a

Coldfire device at maximum clock rate?

Does the C-compiler has ASM-inline capabilities?

Re: newbie questions

JimDon — Sat, 28 Jun 2008 22:05:27 GMT

The V1 executes 8-12 times faster than the HCS08.

It's one thing to code perhaps some small amount of critical code in asm, once you find the need.
However, designing at a high level, "C" lets you write code that is better designed, easier to debug and more likely to port. Perhaps you are a hobbyist and your time means nothing, but for a paying job you need to use "C" for the most part, as it is faster to develop, and more importantly quicker to debug.

It is also more reliable in the long run.

Message Edited by JimDon on 2008-06-28 11:07 AM

Re: newbie questions

gbaars — Sat, 28 Jun 2008 23:28:21 GMT

The idea is to use the MCF51 for DSP purposes.

Do you think sufficient troughput is possible with

samplerates 10+ ksps for various sorts of digital

(FIR/FFT) processing when C is used.

Re: newbie questions

JimDon — Sun, 29 Jun 2008 06:14:51 GMT

Hard to say.
Why not try it and see?

Presumable you have (or can find) the algorithm in "C". Write some test code, and toggle a bit at the top of the routine and the look at it with a scope.

I believe code also runs faster from ram and you do have 16K on that chip as well.