Microcontroller for simple automotive application?

[[email protected]]

Hi !

I'm about to design a simple controller for autmotive area - measuring
4 temperatures, controlling 4 solenoids, nothing significant beside
that actually. Computing power is not an issue here, application is
simple. Device is going to be powered from car 12V installation,
obviously. It's not going into high volume, it's to support my friend's
car experiments. It's a bit similar to devices used together with car
gas systems.

1. I'd like to use Atmel AVR's for that, as this architecture I'm most
familiar with. Unfrotunately I've heard some rumours about AVRs being
more sensitive to interferences (is this the right word?), power
quality etc. Some people recommend PICs as being more immune. Is there
really a difference between these 2 families?

And yes, I understand the importance of proper design

2. Regardles of the uC chosen, I'd like to use some good external
supervisory (reset + watchdog) circuit. Can someone recommend some good
one for this application (whatever you've used and found reliable)?

3. I need 4 high-side switches to control my solenoids. For higher
reliability I'd probably use one of integrated switches with
overvoltage/temp protection. There are some with SPI control and status
readback, which sounds attractive. I've seen such devices from
ST,Atmel,Freescale, yet this kind of devices seem to be not so easy to
get in small quantities. Could someone point me to other companies
doing this kind of chips?

Best Regards,
Przemyslaw

 

[Nico Coesel]

Hi !

I'm about to design a simple controller for autmotive area - measuring
4 temperatures, controlling 4 solenoids, nothing significant beside
that actually. Computing power is not an issue here, application is
simple. Device is going to be powered from car 12V installation,
obviously. It's not going into high volume, it's to support my friend's
car experiments. It's a bit similar to devices used together with car
gas systems.

1. I'd like to use Atmel AVR's for that, as this architecture I'm most
familiar with. Unfrotunately I've heard some rumours about AVRs being
more sensitive to interferences (is this the right word?), power
quality etc. Some people recommend PICs as being more immune. Is there
really a difference between these 2 families?

And yes, I understand the importance of proper design

2. Regardles of the uC chosen, I'd like to use some good external
supervisory (reset + watchdog) circuit. Can someone recommend some good
one for this application (whatever you've used and found reliable)?

3. I need 4 high-side switches to control my solenoids. For higher
reliability I'd probably use one of integrated switches with
overvoltage/temp protection. There are some with SPI control and status
readback, which sounds attractive. I've seen such devices from
ST,Atmel,Freescale, yet this kind of devices seem to be not so easy to
get in small quantities. Could someone point me to other companies
doing this kind of chips?

I switched to MSP430 (texas instruments) for the kind of circuits you
want to build and I have no regrets leaving the 8051 architecture.

 

[Adrian Jansen]

Processor family is almost irrelevant. What is relevant is good
grounding, good shielding, and spike suppression.
Rumours about sensitivity are almost always generated by people who by
accident create a marginally better design than the previous disaster.


--
Regards,

Adrian Jansen adrianjansen at internode dot on dot net
Design Engineer J & K Micro Systems
Microcomputer solutions for industrial control
Note reply address is invalid, convert address above to machine form.

 

[Homer J Simpson]

1. I'd like to use Atmel AVR's for that, as this architecture I'm most
familiar with. Unfrotunately I've heard some rumours about AVRs being
more sensitive to interferences (is this the right word?), power
quality etc.

I believe this is one of the most hostile environments for electronics that
you can imagine. Expect to have a fine collection of dead 'insects' when you
are done.


--
++++++++++++++++++++++++++++++++++++++++++++++++++++
+ Required crap appended to avoid restrictions imposed by brain +
+ damaged idiots.
+
+ Server Response: '441 Posting Failed (Rejected by POST filter)', +
+ Port: 119, Secure(SSL): No, Server Error: 441,
+
+ Error Number: 0x800CCCA9
+
++++++++++++++++++++++++++++++++++++++++++++++++++++

 

[martin.shoebridge]

A good start is a filter in EVERY line, including ground.......

 

[Jonathan Kirwan]

I think the processor line is a little 'thin' and may not be
applicable to your case, at all, but I believe Analog Devices has a
new family (if you can call it that, just yet) of processors designed
for automotive applications and that can take and operate from
something like 35-40V on their Vcc.

http://www.analog.com/en/press/0,2890,3%5F%5F111916,00.html

"Powered directly from the car battery, the single-chip ADuC703x
devices integrate up to three 16-bit analog-to-digital converters
(ADCs), an ARM7 microcontroller, a local interconnect network (LIN)
transceiver, embedded flash memory, an on-chip PGA (programmable gain
amplifier) for a wide range of current measurements, on-chip
attenuation resistors for direct battery voltage measurement and
external or on-chip temperature sensing..."

Just a thought.

Jon

 

[Zak]

I think the processor line is a little 'thin' and may not be
applicable to your case, at all, but I believe Analog Devices has a
new family (if you can call it that, just yet) of processors designed
for automotive applications and that can take and operate from
something like 35-40V on their Vcc.

http://www.analog.com/en/press/0,2890,3%5F%5F111916,00.html

4 K or RAM and 96 K or flash for a battery monitor? Software bloat goes
on...


Thomas

 

[Jonathan Kirwan]

4 K or RAM and 96 K or flash for a battery monitor? Software bloat goes
on...

Hehe. What's more interesting to me is that it runs straight off the
battery posts of a car, according to my skim of that page and lack of
deeper experience to know any better. Given some of the hash one can
expect with starting, turning off, and so on, that sounds a bit too
good to be true.

Jon