Controller not power up during slowly varying the input voltage……

[karthickb3e]

Hi all,
I am using MSP430G2152 controller for my project. I am using the 8MHz calibrated clock. At power up, the controller not works, but the voltage at supply pin and reset pin is at correct level. This problem occurs repeatedly while slowly varying (I am using variable power supply at input side (0 – 30)V dc.. there is 3.3 V regulator in the power supply circuit) the input voltage at power supply… Please give suggestions to solve my problem….

I checked the same program(but timing values changed as to the 1Mhz Clock frequency) in 1MHz calibrated clock, this problem not occurs.. But I need higher speed of operation(on 1Mhz Clock frequency) so suggest solving the problem…….

 

[sky_123]

Hi, you could delay the reset (e.g using a dedicated reset device, there are 3-pin ones available). Hopefully that may fix the issue.

 

[karthickb3e]

sorry sky_123...
i dont understand yoyr answer
(e.g using a dedicated reset device, there are 3-pin ones available)

 

[sky_123]

if the power is ramping, maybe the microcontroller will not get initialized properly. To fix that, you can try to reset your
microcontroller after the power is stable. To do that, there are some reset ICs (e.g. ST Micro make some from memory)
that invoke a reset after a certain number of milliseconds.

 

[karthickb3e]

is this can be done within software with out the other external hardware....

 

[sky_123]

It can't be fixed in software if the processor is not starting up correctly. Without any external hardware you'd have to ensure there
is no ramp-up of the input voltage. You could try to investigate the 3.3v regulator. Sometimes there is a capacitor which implements
a soft-start (to eliminate surge current), which you could try to reduce the value of.