Which microcontroller is best for simple 120-220V control?

"M.Randelzhofer" <techseller@gmx.de> skrev i meddelandet 
news:3rt30tFl49ldU1@individual.net...
> "Jim" <tech@picmodules.com> schrieb im Newsbeitrag
> news:nw96f.1280$Jl3.495@newsfe4-gui.ntli.net...
>>
>> I agree. The MSP430 is nice... but my only reservation for a battery
> backed
>> unit is that there is no brownout feature on the MSP430. As a result of
> the
>> changeover and subsequent draining of the backup battery you may, (and I
>> know first hand knowledge of this), suffer from a micro lockup. Your main
>> power comes back online, only for your processor lock.  Add an external
>> reset/brownout circuit and you'll be on to a winner.! :-)
>>
>> Jim
>> www.picmodules.com
>>
>>
>
> All MSP430 devices but the older '11x1 and '149 have the brownout feature.
>


Looking at the MSP430x11x2 datasheet,  The trigger point is max 0,7 * 
V(B_IT-) = 0,7 * 1,71 = 1,197 V.
But the datasheet only seems to guarantee operation downto 1.8V ???
(Not to mention that the flash requires 2,7 V to program)
I think you *need* external brownout for these circuits.
Anyone can spread more light on this?


-- 
Best Regards,
Ulf Samuelsson
This is intended to be my personal opinion which may,
or may bot be shared by my employer Atmel Nordic AB 

"Ulf Samuelsson" <ulf@a-t-m-e-l.com> schrieb im Newsbeitrag
news:KFt6f.1340$zn6.988@nntpserver.swip.net...
> "M.Randelzhofer" <techseller@gmx.de> skrev i meddelandet
> news:3rt30tFl49ldU1@individual.net...
> > "Jim" <tech@picmodules.com> schrieb im Newsbeitrag
> > news:nw96f.1280$Jl3.495@newsfe4-gui.ntli.net...
> >>
> >> I agree. The MSP430 is nice... but my only reservation for a battery
> > backed
> >> unit is that there is no brownout feature on the MSP430. As a result of
> > the
> >> changeover and subsequent draining of the backup battery you may, (and
I
> >> know first hand knowledge of this), suffer from a micro lockup. Your
main
> >> power comes back online, only for your processor lock.  Add an external
> >> reset/brownout circuit and you'll be on to a winner.! :-)
> >>
> >> Jim
> >> www.picmodules.com
> >>
> >>
> >
> > All MSP430 devices but the older '11x1 and '149 have the brownout
feature.
> >
>
>
> Looking at the MSP430x11x2 datasheet,  The trigger point is max 0,7 *
> V(B_IT-) = 0,7 * 1,71 = 1,197 V.
> But the datasheet only seems to guarantee operation downto 1.8V ???
> (Not to mention that the flash requires 2,7 V to program)
> I think you *need* external brownout for these circuits.
> Anyone can spread more light on this?
>
>
> -- 
> Best Regards,
> Ulf Samuelsson
> This is intended to be my personal opinion which may,
> or may bot be shared by my employer Atmel Nordic AB
>
>

I exactly asked this question last year at the TI ATC 2004 in
Freising/Germany.
They told me, that for worst-worst case calculations an external brownout
detector can be used (Yes, they smiled). On the larger devices the threshold
of the BOR is programmable (SVS).

In smaller devices, the integrated BOR is primarily designed for proper
startup on insertion of batteries, where the BORless devices often hang up.

In my own tests, the MSP's with BOR start up properly at voltages above
1,2-1,3V at room temperature.

Writing to Flash needs an extra supervisory circuit or an integrated ADC to
measure VCC, which can be done internally, to insure that VCC is > 2,7 or >
2,2 V (on the newer 'F2xxx devices).

MIKE

>>>
>>> All MSP430 devices but the older '11x1 and '149 have the brownout
feature.
>>
>> Looking at the MSP430x11x2 datasheet,  The trigger point is max 0,7 *
>> V(B_IT-) = 0,7 * 1,71 = 1,197 V.
>> But the datasheet only seems to guarantee operation downto 1.8V ???
>> (Not to mention that the flash requires 2,7 V to program)
>> I think you *need* external brownout for these circuits.
>> Anyone can spread more light on this?
>>
>>
>
> I exactly asked this question last year at the TI ATC 2004 in
> Freising/Germany.
> They told me, that for worst-worst case calculations an external
> brownout detector can be used (Yes, they smiled). On the larger
> devices the threshold of the BOR is programmable (SVS).
>



> In smaller devices, the integrated BOR is primarily designed for
> proper startup on insertion of batteries, where the BORless devices
> often hang up.
>
> In my own tests, the MSP's with BOR start up properly at voltages
> above 1,2-1,3V at room temperature.
>

Question is what frequency is safe....
Dropping the voltage will typically reduce the frwequency where the device
operates properly.
Testing on one batch of silicon does not mean that the next batch of silicon
will behave in the same way.
The nature of semiconductor processes nmeans that there will be variations
between lots.

Typically the Power On reset circuits (which is a more proper name than BOD)
will detect the low voltage and then generate an internal reset for some
time.
The voltage is expected to rise to a valid value (1,8V) before the internal
reset is deasserted.

Some batches may be operational at 1.3 V, but if a batch turns up that is
not
operational below 1,8V you are in trouble.
No Semiconductor will admit a problem if you run the part outside the spec.

> Writing to Flash needs an extra supervisory circuit or an integrated
> ADC to measure VCC, which can be done internally, to insure that VCC
> is > 2,7 or > 2,2 V (on the newer 'F2xxx devices).
>
Measuring with the ADC does not protect you against the voltage dropping
after the measurement is complete.
If you need selfprogramming, you need a Brownout at > 2,7V

I think in practice you have to have an external Brownout > 2,7 V for the
design to work
with


> MIKE

-- 
Best Regards,
Ulf Samuelsson
ulf@a-t-m-e-l.com
This message is intended to be my own personal view and it
may or may not be shared by my employer Atmel Nordic AB

Ulf Samuelsson wrote:
> Question is what frequency is safe....
> Dropping the voltage will typically reduce the frwequency where the device
> operates properly.
> Testing on one batch of silicon does not mean that the next batch of silicon
> will behave in the same way.
> The nature of semiconductor processes nmeans that there will be variations
> between lots.
> 
> Typically the Power On reset circuits (which is a more proper name than BOD)
> will detect the low voltage and then generate an internal reset for some
> time.
> The voltage is expected to rise to a valid value (1,8V) before the internal
> reset is deasserted.

That's maybe ok for a RampUP, but true brownout is a fading Vcc, and
this is the issue allude to : You can go outside the legal Vcc/Fmax profile.

Many vendors spec's actually have sizable gaps between the Vcc[min] and 
V[bod], where there is no coverage, and no comeback !

The ideal device would have sub 1uA BOD and programmable threshold, to
allow system margining.
Of course, those threshold-set fuses need to be read at
a very low threshold, to give proper coverage....

The AVRs show appx 20uA BOD current, [programmable Threshold] OK for a 
uC, but not as good as Maxim's < 500nA for BOD _and_ WDOG. [NB: above 
threshold] Xicor made 500nA voltage references, but this territory is
non trivial .

TI claim < 500nA for the very newest MSPs [BOD+OSC?], but full info is 
not released yet...

-jg

"A.P. Richelieu" <a.p@richelieu.com> wrote in message
news:wla6f.983$zn6.661@nntpserver.swip.net...
> "Hans M&#4294967295;ller" <heintest@web.de> skrev i meddelandet
> news:43578cd3$0$12662$9b4e6d93@newsread4.arcor-online.net...
> >I would suggest an AVR Family Member since it's
> >
> > - cheap
> > - there are devices in PDIP housings, ideal for prototype
> > - there is a freeware c compiler (afair also a c++ environment - but do
> > you realy need c++ on a microcontroller ?) and some commercial c, pascal
> > or basic compiler
> > - the devices have some cmos ram, eeprom, flash eprom; some have a
> > secondary x-tal for clock applications.
> >
> > have a look on the atmel avr application notes.
> >
> > hth.
> >
> > hans
>
> Won't disagree with the AVR recommendation ;-)
>
> Probably you should be able to do a nice job with the ATmega48/88/168.
>
> Tools for the AVR:
> STK500 development board (< $100). With this you can program your part.
> AVR Studio now supports GNU C compilers (WinAVR)
>     Downloadable from www.avrfreaks.net
> Otherwise there are free versions (code limited) from
> IAR : IAR will support Embedded C++
> Imagecraft
> etc.
> A JTAGICE Mk II will allow you to program and debug.


I found AVR Studio to be compeltely inadequate buggy and poorly written.
COmpared even to Keil apps.

Jona Vark <noemail@all.com> wrote:

[...]
> 
> I found AVR Studio to be compeltely inadequate buggy and poorly written.

   And it even seems to get worse with every revision, unfortunately...

-- 
http://www.flexusergroup.com/

You guys are really great.  You have helped me narrow my search to
either the AVR or MSP430 microcontrollers.  As you observed, I am not
constrained by software compatability.

I do have a development environment compatability issue, so I would
like to once again prevail upon you for advice.  Currently I use the
following development platform for engineering software,

    gcc/g++/gdb
    SlickEdit 10 IDE
    Red Hat Enterprise 3 Linux
    Pentium 4 and Opteron

I would prefer to use this same environment, ideally just adding a tool
or two for embedded software development.

To summarize your development recommendations, thus far you have
commented that AVR Studio is not so good.  I hear nice things about
Microsoft Visual Studio, but that would require a change to Windows.

So, which microcontroller is supported by development tools that best
fit my development environment?

Both are supported by GCC compiler.
AVR has the better commercial C compiler.
The 430 commercial compiler is suspect, IMO.

"Voom" <google@voom.net> wrote in message 
news:1130606410.085240.121330@z14g2000cwz.googlegroups.com...
> You guys are really great.  You have helped me narrow my search to
> either the AVR or MSP430 microcontrollers.  As you observed, I am not
> constrained by software compatability.
>
> I do have a development environment compatability issue, so I would
> like to once again prevail upon you for advice.  Currently I use the
> following development platform for engineering software,
>
>    gcc/g++/gdb
>    SlickEdit 10 IDE
>    Red Hat Enterprise 3 Linux
>    Pentium 4 and Opteron
>
> I would prefer to use this same environment, ideally just adding a tool
> or two for embedded software development.
>
> To summarize your development recommendations, thus far you have
> commented that AVR Studio is not so good.  I hear nice things about
> Microsoft Visual Studio, but that would require a change to Windows.
>
> So, which microcontroller is supported by development tools that best
> fit my development environment?
>