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Discussion Groups | MSP430 | MSP430FE427A does not start with quick power restoration
The purpose of this group is to foster exchange of information on the Texas Instruments MSP430 family of microcontrollers and related tools. Everyone welcome, all levels of familiarity/expertise.
MSP430FE427A does not start with quick power restoration - Sameh H - Oct 5 15:10:57 2009
I'm using the MSP430FE427A, the data-sheet mentioned that the Avcc (Analog Vcc) should not
be started before the Dvcc (digital Vcc) so I have a 10 ohm Resistor and 10uf Cap.
supplying the Avcc from the Dvcc (a simple delay circuit like the one used in the meter
application note)
I noticed that when I lose the powe for 1-15 seconed then when the power comes back the MCU does not start again until I reset the device.
but if I lost the power for more than 15 sec. then I reconnect it, the MCU works fine!!
I was suspecting that the Cap. at the Avcc was not losing the charge a quick as the Cap. at the Dvcc. (by so the Avcc is supplied before the Dvcc when the power comes back) So I hocked the oscilloscope to both caps. I noticed that in normal case the Avcc is lower than the Dvcc (which is expected because there is a R source the Avcc from the Dvcc) then when I lose the power both loses the charges together until they have the same voltage (around 2.9V) and stay together for a 10-15 second then they drop quickly to 0v.
Case 2: MCU work fine then I disconnect then I connected the power quickly withen 1-15 sec. the MCU will not start and the Dvcc and Avcc will have the same voltage like they were internally shorted. and the device will not work until I reset it
Am I working in the right area? how can I fix this issue?
------------------------------------
______________________________
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Real-world software for real-time control. Details Here!
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I noticed that when I lose the powe for 1-15 seconed then when the power comes back the MCU does not start again until I reset the device.
but if I lost the power for more than 15 sec. then I reconnect it, the MCU works fine!!
I was suspecting that the Cap. at the Avcc was not losing the charge a quick as the Cap. at the Dvcc. (by so the Avcc is supplied before the Dvcc when the power comes back) So I hocked the oscilloscope to both caps. I noticed that in normal case the Avcc is lower than the Dvcc (which is expected because there is a R source the Avcc from the Dvcc) then when I lose the power both loses the charges together until they have the same voltage (around 2.9V) and stay together for a 10-15 second then they drop quickly to 0v.
Case 2: MCU work fine then I disconnect then I connected the power quickly withen 1-15 sec. the MCU will not start and the Dvcc and Avcc will have the same voltage like they were internally shorted. and the device will not work until I reset it
Am I working in the right area? how can I fix this issue?
------------------------------------
______________________________
controlSUITE™ software. Comprehensive. Intuitive. Optimized.
Real-world software for real-time control. Details Here!
(You need to be a member of msp430 -- send a blank email to msp430-subscribe@yahoogroups.com )
Re: MSP430FE427A does not start with quick power restoration - old_cow_yellow - Oct 5 16:28:58 2009
I think the 10 ohm resistor has nothing to do with your problem.
What MCLK frequency are you using? I thing the firmware crashed when DVcc drops below around 2.9V.
What is the total capacitance of all the capacitors connected to DVcc and AVcc? If not excessive (<100 uF), adding a 1 kohm resistor from DVcc to DVss may solve your problem.
--- In m...@yahoogroups.com, "Sameh H" wrote:
>
> I'm using the MSP430FE427A, the data-sheet mentioned that the Avcc (Analog Vcc) should not be started before the Dvcc (digital Vcc) so I have a 10 ohm Resistor and 10uf Cap. supplying the Avcc from the Dvcc (a simple delay circuit like the one used in the meter application note)
>
> I noticed that when I lose the powe for 1-15 seconed then when the power comes back the MCU does not start again until I reset the device.
>
> but if I lost the power for more than 15 sec. then I reconnect it, the MCU works fine!!
>
> I was suspecting that the Cap. at the Avcc was not losing the charge a quick as the Cap. at the Dvcc. (by so the Avcc is supplied before the Dvcc when the power comes back) So I hocked the oscilloscope to both caps. I noticed that in normal case the Avcc is lower than the Dvcc (which is expected because there is a R source the Avcc from the Dvcc) then when I lose the power both loses the charges together until they have the same voltage (around 2.9V) and stay together for a 10-15 second then they drop quickly to 0v.
>
> Case 2: MCU work fine then I disconnect then I connected the power quickly withen 1-15 sec. the MCU will not start and the Dvcc and Avcc will have the same voltage like they were internally shorted. and the device will not work until I reset it
>
> Am I working in the right area? how can I fix this issue?
>
------------------------------------
______________________________
controlSUITE™ software. Comprehensive. Intuitive. Optimized.
Real-world software for real-time control. Details Here!
(You need to be a member of msp430 -- send a blank email to msp430-subscribe@yahoogroups.com )
What MCLK frequency are you using? I thing the firmware crashed when DVcc drops below around 2.9V.
What is the total capacitance of all the capacitors connected to DVcc and AVcc? If not excessive (<100 uF), adding a 1 kohm resistor from DVcc to DVss may solve your problem.
--- In m...@yahoogroups.com, "Sameh H"
>
> I'm using the MSP430FE427A, the data-sheet mentioned that the Avcc (Analog Vcc) should not be started before the Dvcc (digital Vcc) so I have a 10 ohm Resistor and 10uf Cap. supplying the Avcc from the Dvcc (a simple delay circuit like the one used in the meter application note)
>
> I noticed that when I lose the powe for 1-15 seconed then when the power comes back the MCU does not start again until I reset the device.
>
> but if I lost the power for more than 15 sec. then I reconnect it, the MCU works fine!!
>
> I was suspecting that the Cap. at the Avcc was not losing the charge a quick as the Cap. at the Dvcc. (by so the Avcc is supplied before the Dvcc when the power comes back) So I hocked the oscilloscope to both caps. I noticed that in normal case the Avcc is lower than the Dvcc (which is expected because there is a R source the Avcc from the Dvcc) then when I lose the power both loses the charges together until they have the same voltage (around 2.9V) and stay together for a 10-15 second then they drop quickly to 0v.
>
> Case 2: MCU work fine then I disconnect then I connected the power quickly withen 1-15 sec. the MCU will not start and the Dvcc and Avcc will have the same voltage like they were internally shorted. and the device will not work until I reset it
>
> Am I working in the right area? how can I fix this issue?
>
------------------------------------
______________________________
controlSUITE™ software. Comprehensive. Intuitive. Optimized.
Real-world software for real-time control. Details Here!
(You need to be a member of msp430 -- send a blank email to msp430-subscribe@yahoogroups.com )
Re: MSP430FE427A does not start with quick power restoration - Sameh H - Oct 7 4:35:41 2009
MCLK is 8Mhz
I'm using 10uf atthe Dvcc and 10uf at the Avcc
if I connected the 1K resistor from the Dvcc to Dvss, it will consume the charges remaining in the Cap. which might solve the problem because the reset condition will happen sooner. but I will lose the time needed for saving the data into the memory when the power supply is off.
is there is a software reset command?
--- In m...@yahoogroups.com, "old_cow_yellow" wrote:
>
> I think the 10 ohm resistor has nothing to do with your problem.
>
> What MCLK frequency are you using? I thing the firmware crashed when DVcc drops below around 2.9V.
>
> What is the total capacitance of all the capacitors connected to DVcc and AVcc? If not excessive (<100 uF), adding a 1 kohm resistor from DVcc to DVss may solve your problem.
>
> --- In m...@yahoogroups.com, "Sameh H" wrote:
> >
> > I'm using the MSP430FE427A, the data-sheet mentioned that the Avcc (Analog Vcc) should not be started before the Dvcc (digital Vcc) so I have a 10 ohm Resistor and 10uf Cap. supplying the Avcc from the Dvcc (a simple delay circuit like the one used in the meter application note)
> >
> > I noticed that when I lose the powe for 1-15 seconed then when the power comes back the MCU does not start again until I reset the device.
> >
> > but if I lost the power for more than 15 sec. then I reconnect it, the MCU works fine!!
> >
> > I was suspecting that the Cap. at the Avcc was not losing the charge a quick as the Cap. at the Dvcc. (by so the Avcc is supplied before the Dvcc when the power comes back) So I hocked the oscilloscope to both caps. I noticed that in normal case the Avcc is lower than the Dvcc (which is expected because there is a R source the Avcc from the Dvcc) then when I lose the power both loses the charges together until they have the same voltage (around 2.9V) and stay together for a 10-15 second then they drop quickly to 0v.
> >
> > Case 2: MCU work fine then I disconnect then I connected the power quickly withen 1-15 sec. the MCU will not start and the Dvcc and Avcc will have the same voltage like they were internally shorted. and the device will not work until I reset it
> >
> > Am I working in the right area? how can I fix this issue?
>
------------------------------------
______________________________
controlSUITE™ software. Comprehensive. Intuitive. Optimized.
Real-world software for real-time control. Details Here!
(You need to be a member of msp430 -- send a blank email to msp430-subscribe@yahoogroups.com )
I'm using 10uf atthe Dvcc and 10uf at the Avcc
if I connected the 1K resistor from the Dvcc to Dvss, it will consume the charges remaining in the Cap. which might solve the problem because the reset condition will happen sooner. but I will lose the time needed for saving the data into the memory when the power supply is off.
is there is a software reset command?
--- In m...@yahoogroups.com, "old_cow_yellow"
>
> I think the 10 ohm resistor has nothing to do with your problem.
>
> What MCLK frequency are you using? I thing the firmware crashed when DVcc drops below around 2.9V.
>
> What is the total capacitance of all the capacitors connected to DVcc and AVcc? If not excessive (<100 uF), adding a 1 kohm resistor from DVcc to DVss may solve your problem.
>
> --- In m...@yahoogroups.com, "Sameh H"
> >
> > I'm using the MSP430FE427A, the data-sheet mentioned that the Avcc (Analog Vcc) should not be started before the Dvcc (digital Vcc) so I have a 10 ohm Resistor and 10uf Cap. supplying the Avcc from the Dvcc (a simple delay circuit like the one used in the meter application note)
> >
> > I noticed that when I lose the powe for 1-15 seconed then when the power comes back the MCU does not start again until I reset the device.
> >
> > but if I lost the power for more than 15 sec. then I reconnect it, the MCU works fine!!
> >
> > I was suspecting that the Cap. at the Avcc was not losing the charge a quick as the Cap. at the Dvcc. (by so the Avcc is supplied before the Dvcc when the power comes back) So I hocked the oscilloscope to both caps. I noticed that in normal case the Avcc is lower than the Dvcc (which is expected because there is a R source the Avcc from the Dvcc) then when I lose the power both loses the charges together until they have the same voltage (around 2.9V) and stay together for a 10-15 second then they drop quickly to 0v.
> >
> > Case 2: MCU work fine then I disconnect then I connected the power quickly withen 1-15 sec. the MCU will not start and the Dvcc and Avcc will have the same voltage like they were internally shorted. and the device will not work until I reset it
> >
> > Am I working in the right area? how can I fix this issue?
>
------------------------------------
______________________________
controlSUITE™ software. Comprehensive. Intuitive. Optimized.
Real-world software for real-time control. Details Here!
(You need to be a member of msp430 -- send a blank email to msp430-subscribe@yahoogroups.com )
Re: Re: MSP430FE427A does not start with quick power restoration - Joe Radomski - Oct 7 5:27:14 2009
the only "software" reset is to causse an invalid access liek writing to th=
e flash registers with teh wrong password..=20
=A0
What appeas to be happing is that the voltage is dropping below what is nec=
essary to run at 8mhz, you cant let this happen as the processor will lock =
up, it will NOT reset until the voltage drops below the BOR level, if the v=
oltage restores without dropping low enough for a BOR the processor will=A0=
remain hung up.. The only solutions you have is to either use the resistor =
as suggested or set the SVS to cause a hard reset when a certain voltage is=
met.. If you need to run at a lower voltage you need to run at a lower clo=
ck rate to prevent processor lock up.. depending on how critical the levls =
are yo might be ablt to monitor for 1 voltage, when that limit is exceeded =
drop the processor frequency, the save you results (as long as its not in f=
lash) as the flash also generally needs a higher voltage to program..
=A0
=A0
=A0
--- On Wed, 10/7/09, Sameh H wrote:
From: Sameh H
Subject: [msp430] Re: MSP430FE427A does not start with quick power restorat=
ion
To: m...@yahoogroups.com
Date: Wednesday, October 7, 2009, 4:35 AM
=A0=20
MCLK is 8Mhz
I'm using 10uf atthe Dvcc and 10uf at the Avcc
if I connected the 1K resistor from the Dvcc to Dvss, it will consume the c=
harges remaining in the Cap. which might solve the problem because the rese=
t condition will happen sooner. but I will lose the time needed for saving =
the data into the memory when the power supply is off.
is there is a software reset command?
--- In msp430@yahoogroups. com, "old_cow_yellow" wrot=
e:
>
> I think the 10 ohm resistor has nothing to do with your problem.
>=20
> What MCLK frequency are you using? I thing the firmware crashed when DVcc=
drops below around 2.9V.
>=20
> What is the total capacitance of all the capacitors connected to DVcc and=
AVcc? If not excessive (<100 uF), adding a 1 kohm resistor from DVcc to DV=
ss may solve your problem.
>=20
> --- In msp430@yahoogroups. com, "Sameh H" wrote:
> >
> > I'm using the MSP430FE427A, the data-sheet mentioned that the Avcc (Ana=
log Vcc) should not be started before the Dvcc (digital Vcc) so I have a 10=
ohm Resistor and 10uf Cap. supplying the Avcc from the Dvcc (a simple dela=
y circuit like the one used in the meter application note)
> >=20
> > I noticed that when I lose the powe for 1-15 seconed then when the powe=
r comes back the MCU does not start again until I reset the device.
> >=20
> > but if I lost the power for more than 15 sec. then I reconnect it, the =
MCU works fine!!
> >=20
> > I was suspecting that the Cap. at the Avcc was not losing the charge a =
quick as the Cap. at the Dvcc. (by so the Avcc is supplied before the Dvcc =
when the power comes back) So I hocked the oscilloscope to both caps. I not=
iced that in normal case the Avcc is lower than the Dvcc (which is expected=
because there is a R source the Avcc from the Dvcc) then when I lose the p=
ower both loses the charges together until they have the same voltage (arou=
nd 2.9V) and stay together for a 10-15 second then they drop quickly to 0v.
> >=20
> > Case 2: MCU work fine then I disconnect then I connected the power quic=
kly withen 1-15 sec. the MCU will not start and the Dvcc and Avcc will have=
the same voltage like they were internally shorted. and the device will no=
t work until I reset it
> >=20
> > Am I working in the right area? how can I fix this issue?
>
[Non-text portions of this message have been removed]
------------------------------------
(You need to be a member of msp430 -- send a blank email to msp430-subscribe@yahoogroups.com )
e flash registers with teh wrong password..=20
=A0
What appeas to be happing is that the voltage is dropping below what is nec=
essary to run at 8mhz, you cant let this happen as the processor will lock =
up, it will NOT reset until the voltage drops below the BOR level, if the v=
oltage restores without dropping low enough for a BOR the processor will=A0=
remain hung up.. The only solutions you have is to either use the resistor =
as suggested or set the SVS to cause a hard reset when a certain voltage is=
met.. If you need to run at a lower voltage you need to run at a lower clo=
ck rate to prevent processor lock up.. depending on how critical the levls =
are yo might be ablt to monitor for 1 voltage, when that limit is exceeded =
drop the processor frequency, the save you results (as long as its not in f=
lash) as the flash also generally needs a higher voltage to program..
=A0
=A0
=A0
--- On Wed, 10/7/09, Sameh H
From: Sameh H
Subject: [msp430] Re: MSP430FE427A does not start with quick power restorat=
ion
To: m...@yahoogroups.com
Date: Wednesday, October 7, 2009, 4:35 AM
=A0=20
MCLK is 8Mhz
I'm using 10uf atthe Dvcc and 10uf at the Avcc
if I connected the 1K resistor from the Dvcc to Dvss, it will consume the c=
harges remaining in the Cap. which might solve the problem because the rese=
t condition will happen sooner. but I will lose the time needed for saving =
the data into the memory when the power supply is off.
is there is a software reset command?
--- In msp430@yahoogroups. com, "old_cow_yellow"
e:
>
> I think the 10 ohm resistor has nothing to do with your problem.
>=20
> What MCLK frequency are you using? I thing the firmware crashed when DVcc=
drops below around 2.9V.
>=20
> What is the total capacitance of all the capacitors connected to DVcc and=
AVcc? If not excessive (<100 uF), adding a 1 kohm resistor from DVcc to DV=
ss may solve your problem.
>=20
> --- In msp430@yahoogroups. com, "Sameh H"
> >
> > I'm using the MSP430FE427A, the data-sheet mentioned that the Avcc (Ana=
log Vcc) should not be started before the Dvcc (digital Vcc) so I have a 10=
ohm Resistor and 10uf Cap. supplying the Avcc from the Dvcc (a simple dela=
y circuit like the one used in the meter application note)
> >=20
> > I noticed that when I lose the powe for 1-15 seconed then when the powe=
r comes back the MCU does not start again until I reset the device.
> >=20
> > but if I lost the power for more than 15 sec. then I reconnect it, the =
MCU works fine!!
> >=20
> > I was suspecting that the Cap. at the Avcc was not losing the charge a =
quick as the Cap. at the Dvcc. (by so the Avcc is supplied before the Dvcc =
when the power comes back) So I hocked the oscilloscope to both caps. I not=
iced that in normal case the Avcc is lower than the Dvcc (which is expected=
because there is a R source the Avcc from the Dvcc) then when I lose the p=
ower both loses the charges together until they have the same voltage (arou=
nd 2.9V) and stay together for a 10-15 second then they drop quickly to 0v.
> >=20
> > Case 2: MCU work fine then I disconnect then I connected the power quic=
kly withen 1-15 sec. the MCU will not start and the Dvcc and Avcc will have=
the same voltage like they were internally shorted. and the device will no=
t work until I reset it
> >=20
> > Am I working in the right area? how can I fix this issue?
>
[Non-text portions of this message have been removed]
------------------------------------
(You need to be a member of msp430 -- send a blank email to msp430-subscribe@yahoogroups.com )
Re: MSP430FE427A does not start with quick power restoration - Michael - Oct 7 10:26:18 2009
> the only "software" reset is to causse an invalid access like
> writing to the flash registers with teh wrong password..=20
But that's not a reset. That won't generate a POR but a PUC. I would recomm=
end writing to the Watchdog with the wrong password instead of the flash (y=
ou may call me paranoid).
> depending on how critical the levels are you might be able to
> monitor for 1 voltage, when that limit is exceeded drop the
> processor frequency, then save you results (as long as its not in
> flash) as the flash also generally needs a higher voltage to
> program..
I don't know if it is the processor or the oscilator circuit that needs a h=
igher voltage to operate at 8MHz. You will have to check on that and see if=
you can simply use the MCLK divisor or if you will need to change to the D=
CO.
The reported 2.9V is over the flash minimum write voltage.
> > if I connected the 1K resistor from the Dvcc to Dvss, it will
> > consume the charges remaining in the Cap. which might solve the
> > problem because the reset condition will happen sooner. but I
> > will lose the time needed for saving the data into the memory
> > when the power supply is off.
As I think somebody else mentioned, you can use digital pins to accelerate =
the discharge speed (one for each Vcc) once you are ready to shutdown the s=
ystem (after saving data).=20
Here is what I'd do:
Use a BAT54C dual common cathode shottky diode. Connect one anode to Dvcc a=
nd the other to Avcc.=20
Connect the common cathode to the collector of an NPN transistor.
Connect the emitter to gnd.
Connect the base through a resistor to a digital output pin.
This way, you only need to drive that output pin to digital 1 and both Avcc=
and Dvcc will equaly and rapidly discharge. You should probably use a resi=
stor to limit the current throught the transistor.
You can improve this by using 2 resistors, one between each Vcc and anode; =
by using a lower value for Avcc than for Dvcc, you can make sure that Avcc =
discharges faster than Dvcc.
If you then put a cap on the digital output pin, you can make sure the tran=
sistor continues to discharge the caps after Vcc drops the MSP below reset =
voltage (at which point outputs may revert to inputs? Don't know for sure).
Best Regards,
Michael K.
--- In m...@yahoogroups.com, Joe Radomski wrote:
>
> the only "software" reset is to causse an invalid access liek writing to =
the flash registers with teh wrong password..=20
> =A0
> What appeas to be happing is that the voltage is dropping below what is n=
ecessary to run at 8mhz, you cant let this happen as the processor will loc=
k up, it will NOT reset until the voltage drops below the BOR level, if the=
voltage restores without dropping low enough for a BOR the processor will=
=A0remain hung up.. The only solutions you have is to either use the resist=
or as suggested or set the SVS to cause a hard reset when a certain voltage=
is met.. If you need to run at a lower voltage you need to run at a lower =
clock rate to prevent processor lock up.. depending on how critical the lev=
ls are yo might be ablt to monitor for 1 voltage, when that limit is exceed=
ed drop the processor frequency, the save you results (as long as its not i=
n flash) as the flash also generally needs a higher voltage to program..
> =A0
> =A0
> =A0
>=20
>=20
> --- On Wed, 10/7/09, Sameh H wrote:
>=20
>=20
> From: Sameh H
> Subject: [msp430] Re: MSP430FE427A does not start with quick power restor=
ation
> To: m...@yahoogroups.com
> Date: Wednesday, October 7, 2009, 4:35 AM
>=20
>=20
> =A0=20
>=20
>=20
>=20
> MCLK is 8Mhz
> I'm using 10uf atthe Dvcc and 10uf at the Avcc
> if I connected the 1K resistor from the Dvcc to Dvss, it will consume the=
charges remaining in the Cap. which might solve the problem because the re=
set condition will happen sooner. but I will lose the time needed for savin=
g the data into the memory when the power supply is off.
>=20
> is there is a software reset command?
>=20
> --- In msp430@yahoogroups. com, "old_cow_yellow" wr=
ote:
> >
> > I think the 10 ohm resistor has nothing to do with your problem.
> >=20
> > What MCLK frequency are you using? I thing the firmware crashed when DV=
cc drops below around 2.9V.
> >=20
> > What is the total capacitance of all the capacitors connected to DVcc a=
nd AVcc? If not excessive (<100 uF), adding a 1 kohm resistor from DVcc to =
DVss may solve your problem.
> >=20
> > --- In msp430@yahoogroups. com, "Sameh H" wrote:
> > >
> > > I'm using the MSP430FE427A, the data-sheet mentioned that the Avcc (A=
nalog Vcc) should not be started before the Dvcc (digital Vcc) so I have a =
10 ohm Resistor and 10uf Cap. supplying the Avcc from the Dvcc (a simple de=
lay circuit like the one used in the meter application note)
> > >=20
> > > I noticed that when I lose the powe for 1-15 seconed then when the po=
wer comes back the MCU does not start again until I reset the device.
> > >=20
> > > but if I lost the power for more than 15 sec. then I reconnect it, th=
e MCU works fine!!
> > >=20
> > > I was suspecting that the Cap. at the Avcc was not losing the charge =
a quick as the Cap. at the Dvcc. (by so the Avcc is supplied before the Dvc=
c when the power comes back) So I hocked the oscilloscope to both caps. I n=
oticed that in normal case the Avcc is lower than the Dvcc (which is expect=
ed because there is a R source the Avcc from the Dvcc) then when I lose the=
power both loses the charges together until they have the same voltage (ar=
ound 2.9V) and stay together for a 10-15 second then they drop quickly to 0=
v.
> > >=20
> > > Case 2: MCU work fine then I disconnect then I connected the power qu=
ickly withen 1-15 sec. the MCU will not start and the Dvcc and Avcc will ha=
ve the same voltage like they were internally shorted. and the device will =
not work until I reset it
> > >=20
> > > Am I working in the right area? how can I fix this issue?
> > >
> >
>=20
>=20
>=20
>=20
>=20
>=20
>=20
>=20
>=20
>=20
>=20
>=20
>=20
>=20
>=20
>=20
> [Non-text portions of this message have been removed]
>
------------------------------------
(You need to be a member of msp430 -- send a blank email to msp430-subscribe@yahoogroups.com )
> writing to the flash registers with teh wrong password..=20
But that's not a reset. That won't generate a POR but a PUC. I would recomm=
end writing to the Watchdog with the wrong password instead of the flash (y=
ou may call me paranoid).
> depending on how critical the levels are you might be able to
> monitor for 1 voltage, when that limit is exceeded drop the
> processor frequency, then save you results (as long as its not in
> flash) as the flash also generally needs a higher voltage to
> program..
I don't know if it is the processor or the oscilator circuit that needs a h=
igher voltage to operate at 8MHz. You will have to check on that and see if=
you can simply use the MCLK divisor or if you will need to change to the D=
CO.
The reported 2.9V is over the flash minimum write voltage.
> > if I connected the 1K resistor from the Dvcc to Dvss, it will
> > consume the charges remaining in the Cap. which might solve the
> > problem because the reset condition will happen sooner. but I
> > will lose the time needed for saving the data into the memory
> > when the power supply is off.
As I think somebody else mentioned, you can use digital pins to accelerate =
the discharge speed (one for each Vcc) once you are ready to shutdown the s=
ystem (after saving data).=20
Here is what I'd do:
Use a BAT54C dual common cathode shottky diode. Connect one anode to Dvcc a=
nd the other to Avcc.=20
Connect the common cathode to the collector of an NPN transistor.
Connect the emitter to gnd.
Connect the base through a resistor to a digital output pin.
This way, you only need to drive that output pin to digital 1 and both Avcc=
and Dvcc will equaly and rapidly discharge. You should probably use a resi=
stor to limit the current throught the transistor.
You can improve this by using 2 resistors, one between each Vcc and anode; =
by using a lower value for Avcc than for Dvcc, you can make sure that Avcc =
discharges faster than Dvcc.
If you then put a cap on the digital output pin, you can make sure the tran=
sistor continues to discharge the caps after Vcc drops the MSP below reset =
voltage (at which point outputs may revert to inputs? Don't know for sure).
Best Regards,
Michael K.
--- In m...@yahoogroups.com, Joe Radomski
>
> the only "software" reset is to causse an invalid access liek writing to =
the flash registers with teh wrong password..=20
> =A0
> What appeas to be happing is that the voltage is dropping below what is n=
ecessary to run at 8mhz, you cant let this happen as the processor will loc=
k up, it will NOT reset until the voltage drops below the BOR level, if the=
voltage restores without dropping low enough for a BOR the processor will=
=A0remain hung up.. The only solutions you have is to either use the resist=
or as suggested or set the SVS to cause a hard reset when a certain voltage=
is met.. If you need to run at a lower voltage you need to run at a lower =
clock rate to prevent processor lock up.. depending on how critical the lev=
ls are yo might be ablt to monitor for 1 voltage, when that limit is exceed=
ed drop the processor frequency, the save you results (as long as its not i=
n flash) as the flash also generally needs a higher voltage to program..
> =A0
> =A0
> =A0
>=20
>=20
> --- On Wed, 10/7/09, Sameh H
>=20
>=20
> From: Sameh H
> Subject: [msp430] Re: MSP430FE427A does not start with quick power restor=
ation
> To: m...@yahoogroups.com
> Date: Wednesday, October 7, 2009, 4:35 AM
>=20
>=20
> =A0=20
>=20
>=20
>=20
> MCLK is 8Mhz
> I'm using 10uf atthe Dvcc and 10uf at the Avcc
> if I connected the 1K resistor from the Dvcc to Dvss, it will consume the=
charges remaining in the Cap. which might solve the problem because the re=
set condition will happen sooner. but I will lose the time needed for savin=
g the data into the memory when the power supply is off.
>=20
> is there is a software reset command?
>=20
> --- In msp430@yahoogroups. com, "old_cow_yellow"
ote:
> >
> > I think the 10 ohm resistor has nothing to do with your problem.
> >=20
> > What MCLK frequency are you using? I thing the firmware crashed when DV=
cc drops below around 2.9V.
> >=20
> > What is the total capacitance of all the capacitors connected to DVcc a=
nd AVcc? If not excessive (<100 uF), adding a 1 kohm resistor from DVcc to =
DVss may solve your problem.
> >=20
> > --- In msp430@yahoogroups. com, "Sameh H"
> > >
> > > I'm using the MSP430FE427A, the data-sheet mentioned that the Avcc (A=
nalog Vcc) should not be started before the Dvcc (digital Vcc) so I have a =
10 ohm Resistor and 10uf Cap. supplying the Avcc from the Dvcc (a simple de=
lay circuit like the one used in the meter application note)
> > >=20
> > > I noticed that when I lose the powe for 1-15 seconed then when the po=
wer comes back the MCU does not start again until I reset the device.
> > >=20
> > > but if I lost the power for more than 15 sec. then I reconnect it, th=
e MCU works fine!!
> > >=20
> > > I was suspecting that the Cap. at the Avcc was not losing the charge =
a quick as the Cap. at the Dvcc. (by so the Avcc is supplied before the Dvc=
c when the power comes back) So I hocked the oscilloscope to both caps. I n=
oticed that in normal case the Avcc is lower than the Dvcc (which is expect=
ed because there is a R source the Avcc from the Dvcc) then when I lose the=
power both loses the charges together until they have the same voltage (ar=
ound 2.9V) and stay together for a 10-15 second then they drop quickly to 0=
v.
> > >=20
> > > Case 2: MCU work fine then I disconnect then I connected the power qu=
ickly withen 1-15 sec. the MCU will not start and the Dvcc and Avcc will ha=
ve the same voltage like they were internally shorted. and the device will =
not work until I reset it
> > >=20
> > > Am I working in the right area? how can I fix this issue?
> > >
> >
>=20
>=20
>=20
>=20
>=20
>=20
>=20
>=20
>=20
>=20
>=20
>=20
>=20
>=20
>=20
>=20
> [Non-text portions of this message have been removed]
>
------------------------------------
(You need to be a member of msp430 -- send a blank email to msp430-subscribe@yahoogroups.com )
Re: MSP430FE427A does not start with quick power restoration - old_cow_yellow - Oct 7 22:00:54 2009
If you use lower MCLK rate, the firmware will not crash at lower DVcc. Read=
the data-sheet.
--- In m...@yahoogroups.com, "Michael" wrote:
>
> > the only "software" reset is to causse an invalid access like
> > writing to the flash registers with teh wrong password..=20
> But that's not a reset. That won't generate a POR but a PUC. I would reco=
mmend writing to the Watchdog with the wrong password instead of the flash =
(you may call me paranoid).
>=20
> > depending on how critical the levels are you might be able to
> > monitor for 1 voltage, when that limit is exceeded drop the
> > processor frequency, then save you results (as long as its not in
> > flash) as the flash also generally needs a higher voltage to
> > program..
> I don't know if it is the processor or the oscilator circuit that needs a=
higher voltage to operate at 8MHz. You will have to check on that and see =
if you can simply use the MCLK divisor or if you will need to change to the=
DCO.
> The reported 2.9V is over the flash minimum write voltage.
>=20
> > > if I connected the 1K resistor from the Dvcc to Dvss, it will
> > > consume the charges remaining in the Cap. which might solve the
> > > problem because the reset condition will happen sooner. but I
> > > will lose the time needed for saving the data into the memory
> > > when the power supply is off.
> As I think somebody else mentioned, you can use digital pins to accelerat=
e the discharge speed (one for each Vcc) once you are ready to shutdown the=
system (after saving data).=20
> Here is what I'd do:
> Use a BAT54C dual common cathode shottky diode. Connect one anode to Dvcc=
and the other to Avcc.=20
> Connect the common cathode to the collector of an NPN transistor.
> Connect the emitter to gnd.
> Connect the base through a resistor to a digital output pin.
>=20
> This way, you only need to drive that output pin to digital 1 and both Av=
cc and Dvcc will equaly and rapidly discharge. You should probably use a re=
sistor to limit the current throught the transistor.
> You can improve this by using 2 resistors, one between each Vcc and anode=
; by using a lower value for Avcc than for Dvcc, you can make sure that Avc=
c discharges faster than Dvcc.
> If you then put a cap on the digital output pin, you can make sure the tr=
ansistor continues to discharge the caps after Vcc drops the MSP below rese=
t voltage (at which point outputs may revert to inputs? Don't know for sure=
).
>=20
> Best Regards,
> Michael K.
>=20
> --- In m...@yahoogroups.com, Joe Radomski wrote:
> >
> > the only "software" reset is to causse an invalid access liek writing t=
o the flash registers with teh wrong password..=20
> > =A0
> > What appeas to be happing is that the voltage is dropping below what is=
necessary to run at 8mhz, you cant let this happen as the processor will l=
ock up, it will NOT reset until the voltage drops below the BOR level, if t=
he voltage restores without dropping low enough for a BOR the processor wil=
l=A0remain hung up.. The only solutions you have is to either use the resis=
tor as suggested or set the SVS to cause a hard reset when a certain voltag=
e is met.. If you need to run at a lower voltage you need to run at a lower=
clock rate to prevent processor lock up.. depending on how critical the le=
vls are yo might be ablt to monitor for 1 voltage, when that limit is excee=
ded drop the processor frequency, the save you results (as long as its not =
in flash) as the flash also generally needs a higher voltage to program..
> > =A0
> > =A0
> > =A0
> >=20
> >=20
> > --- On Wed, 10/7/09, Sameh H wrote:
> >=20
> >=20
> > From: Sameh H
> > Subject: [msp430] Re: MSP430FE427A does not start with quick power rest=
oration
> > To: m...@yahoogroups.com
> > Date: Wednesday, October 7, 2009, 4:35 AM
> >=20
> >=20
> > =A0=20
> >=20
> >=20
> >=20
> > MCLK is 8Mhz
> > I'm using 10uf atthe Dvcc and 10uf at the Avcc
> > if I connected the 1K resistor from the Dvcc to Dvss, it will consume t=
he charges remaining in the Cap. which might solve the problem because the =
reset condition will happen sooner. but I will lose the time needed for sav=
ing the data into the memory when the power supply is off.
> >=20
> > is there is a software reset command?
> >=20
> > --- In msp430@yahoogroups. com, "old_cow_yellow" =
wrote:
> > >
> > > I think the 10 ohm resistor has nothing to do with your problem.
> > >=20
> > > What MCLK frequency are you using? I thing the firmware crashed when =
DVcc drops below around 2.9V.
> > >=20
> > > What is the total capacitance of all the capacitors connected to DVcc=
and AVcc? If not excessive (<100 uF), adding a 1 kohm resistor from DVcc t=
o DVss may solve your problem.
> > >=20
> > > --- In msp430@yahoogroups. com, "Sameh H" wrote:
> > > >
> > > > I'm using the MSP430FE427A, the data-sheet mentioned that the Avcc =
(Analog Vcc) should not be started before the Dvcc (digital Vcc) so I have =
a 10 ohm Resistor and 10uf Cap. supplying the Avcc from the Dvcc (a simple =
delay circuit like the one used in the meter application note)
> > > >=20
> > > > I noticed that when I lose the powe for 1-15 seconed then when the =
power comes back the MCU does not start again until I reset the device.
> > > >=20
> > > > but if I lost the power for more than 15 sec. then I reconnect it, =
the MCU works fine!!
> > > >=20
> > > > I was suspecting that the Cap. at the Avcc was not losing the charg=
e a quick as the Cap. at the Dvcc. (by so the Avcc is supplied before the D=
vcc when the power comes back) So I hocked the oscilloscope to both caps. I=
noticed that in normal case the Avcc is lower than the Dvcc (which is expe=
cted because there is a R source the Avcc from the Dvcc) then when I lose t=
he power both loses the charges together until they have the same voltage (=
around 2.9V) and stay together for a 10-15 second then they drop quickly to=
0v.
> > > >=20
> > > > Case 2: MCU work fine then I disconnect then I connected the power =
quickly withen 1-15 sec. the MCU will not start and the Dvcc and Avcc will =
have the same voltage like they were internally shorted. and the device wil=
l not work until I reset it
> > > >=20
> > > > Am I working in the right area? how can I fix this issue?
> > > >
> > >
> >=20
> >=20
> >=20
> >=20
> >=20
> >=20
> >=20
> >=20
> >=20
> >=20
> >=20
> >=20
> >=20
> >=20
> >=20
> >=20
> > [Non-text portions of this message have been removed]
>
------------------------------------
(You need to be a member of msp430 -- send a blank email to msp430-subscribe@yahoogroups.com )
the data-sheet.
--- In m...@yahoogroups.com, "Michael"
>
> > the only "software" reset is to causse an invalid access like
> > writing to the flash registers with teh wrong password..=20
> But that's not a reset. That won't generate a POR but a PUC. I would reco=
mmend writing to the Watchdog with the wrong password instead of the flash =
(you may call me paranoid).
>=20
> > depending on how critical the levels are you might be able to
> > monitor for 1 voltage, when that limit is exceeded drop the
> > processor frequency, then save you results (as long as its not in
> > flash) as the flash also generally needs a higher voltage to
> > program..
> I don't know if it is the processor or the oscilator circuit that needs a=
higher voltage to operate at 8MHz. You will have to check on that and see =
if you can simply use the MCLK divisor or if you will need to change to the=
DCO.
> The reported 2.9V is over the flash minimum write voltage.
>=20
> > > if I connected the 1K resistor from the Dvcc to Dvss, it will
> > > consume the charges remaining in the Cap. which might solve the
> > > problem because the reset condition will happen sooner. but I
> > > will lose the time needed for saving the data into the memory
> > > when the power supply is off.
> As I think somebody else mentioned, you can use digital pins to accelerat=
e the discharge speed (one for each Vcc) once you are ready to shutdown the=
system (after saving data).=20
> Here is what I'd do:
> Use a BAT54C dual common cathode shottky diode. Connect one anode to Dvcc=
and the other to Avcc.=20
> Connect the common cathode to the collector of an NPN transistor.
> Connect the emitter to gnd.
> Connect the base through a resistor to a digital output pin.
>=20
> This way, you only need to drive that output pin to digital 1 and both Av=
cc and Dvcc will equaly and rapidly discharge. You should probably use a re=
sistor to limit the current throught the transistor.
> You can improve this by using 2 resistors, one between each Vcc and anode=
; by using a lower value for Avcc than for Dvcc, you can make sure that Avc=
c discharges faster than Dvcc.
> If you then put a cap on the digital output pin, you can make sure the tr=
ansistor continues to discharge the caps after Vcc drops the MSP below rese=
t voltage (at which point outputs may revert to inputs? Don't know for sure=
).
>=20
> Best Regards,
> Michael K.
>=20
> --- In m...@yahoogroups.com, Joe Radomski
> >
> > the only "software" reset is to causse an invalid access liek writing t=
o the flash registers with teh wrong password..=20
> > =A0
> > What appeas to be happing is that the voltage is dropping below what is=
necessary to run at 8mhz, you cant let this happen as the processor will l=
ock up, it will NOT reset until the voltage drops below the BOR level, if t=
he voltage restores without dropping low enough for a BOR the processor wil=
l=A0remain hung up.. The only solutions you have is to either use the resis=
tor as suggested or set the SVS to cause a hard reset when a certain voltag=
e is met.. If you need to run at a lower voltage you need to run at a lower=
clock rate to prevent processor lock up.. depending on how critical the le=
vls are yo might be ablt to monitor for 1 voltage, when that limit is excee=
ded drop the processor frequency, the save you results (as long as its not =
in flash) as the flash also generally needs a higher voltage to program..
> > =A0
> > =A0
> > =A0
> >=20
> >=20
> > --- On Wed, 10/7/09, Sameh H
> >=20
> >=20
> > From: Sameh H
> > Subject: [msp430] Re: MSP430FE427A does not start with quick power rest=
oration
> > To: m...@yahoogroups.com
> > Date: Wednesday, October 7, 2009, 4:35 AM
> >=20
> >=20
> > =A0=20
> >=20
> >=20
> >=20
> > MCLK is 8Mhz
> > I'm using 10uf atthe Dvcc and 10uf at the Avcc
> > if I connected the 1K resistor from the Dvcc to Dvss, it will consume t=
he charges remaining in the Cap. which might solve the problem because the =
reset condition will happen sooner. but I will lose the time needed for sav=
ing the data into the memory when the power supply is off.
> >=20
> > is there is a software reset command?
> >=20
> > --- In msp430@yahoogroups. com, "old_cow_yellow"
wrote:
> > >
> > > I think the 10 ohm resistor has nothing to do with your problem.
> > >=20
> > > What MCLK frequency are you using? I thing the firmware crashed when =
DVcc drops below around 2.9V.
> > >=20
> > > What is the total capacitance of all the capacitors connected to DVcc=
and AVcc? If not excessive (<100 uF), adding a 1 kohm resistor from DVcc t=
o DVss may solve your problem.
> > >=20
> > > --- In msp430@yahoogroups. com, "Sameh H"
> > > >
> > > > I'm using the MSP430FE427A, the data-sheet mentioned that the Avcc =
(Analog Vcc) should not be started before the Dvcc (digital Vcc) so I have =
a 10 ohm Resistor and 10uf Cap. supplying the Avcc from the Dvcc (a simple =
delay circuit like the one used in the meter application note)
> > > >=20
> > > > I noticed that when I lose the powe for 1-15 seconed then when the =
power comes back the MCU does not start again until I reset the device.
> > > >=20
> > > > but if I lost the power for more than 15 sec. then I reconnect it, =
the MCU works fine!!
> > > >=20
> > > > I was suspecting that the Cap. at the Avcc was not losing the charg=
e a quick as the Cap. at the Dvcc. (by so the Avcc is supplied before the D=
vcc when the power comes back) So I hocked the oscilloscope to both caps. I=
noticed that in normal case the Avcc is lower than the Dvcc (which is expe=
cted because there is a R source the Avcc from the Dvcc) then when I lose t=
he power both loses the charges together until they have the same voltage (=
around 2.9V) and stay together for a 10-15 second then they drop quickly to=
0v.
> > > >=20
> > > > Case 2: MCU work fine then I disconnect then I connected the power =
quickly withen 1-15 sec. the MCU will not start and the Dvcc and Avcc will =
have the same voltage like they were internally shorted. and the device wil=
l not work until I reset it
> > > >=20
> > > > Am I working in the right area? how can I fix this issue?
> > > >
> > >
> >=20
> >=20
> >=20
> >=20
> >=20
> >=20
> >=20
> >=20
> >=20
> >=20
> >=20
> >=20
> >=20
> >=20
> >=20
> >=20
> > [Non-text portions of this message have been removed]
>
------------------------------------
(You need to be a member of msp430 -- send a blank email to msp430-subscribe@yahoogroups.com )