Re: PIC or Freescale HC08 ??

On Mon, 27 Mar 2006 15:43:41 +0200, the renowned "petrus bitbyter"
<pieterkraltlaatditweg@xxxxxxxxxxxxxxxxx> wrote:


<r.laury@xxxxxxxxxxx> schreef in bericht
news:zfGdnb4JbbkxFrrZnZ2dnUVZ_tqdnZ2d@xxxxxxxxxxxxxx
Hi Group:
I've got a project that I'm contemplating that needs:

To read a keypad with 20 switches.
Control 7 digits of 7 seven segment displays.
Generate pulses for a small stepper motor. (full step and micro step)
Possible control of a brushless servo motor with encoder feedback.
Monitor a few simple sensors.
A few hundred bytes of RAM is enough.
Program size with lookup tables ect, should be under 4-6K.
Flash would be nice.

I've never worked with the PIC and looking at their product line up
there's just too many to chose from.
I have worked with the Motorola stuff (HC05) but they are not making
anymore HC05 parts.
My question is, What PIC would you use to do the above. Or maybe use
several PIC's to get the job done?
Or would you just go for one of the bigger HC08's?

Thanks!
Any input appreciated.

RonL


Ron,

Most important constraint seems to become pincount. Your keypad and display
will require 23 pins.

Nah. Shared lines mean 18 pins max, with no external logic. Might be
possible to do it with 11, depending, still with no external logic.

As a common 40 pins (8 bits) micro has only 36 IO-pins
you may not have enough pins left to meet your requirements. IMHO you hve
several options:
- Bigger micro (more IO-pins, 16 bit type)

There are plenty enough 8-bit micros (as well as 16 and 32-bit) in 64,
80 and 100 pin packages.


Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
speff@xxxxxxxxxxxx Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com
.

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