MSP430 Startuptime from power off mode?

Hi Stephan,

The FRs are probably too new for the datasheet to be completely fleshed out.  For reference, other 5xx parts (which have the same boot process) specify 2 milliseconds typical and 3 ms max.  That's the time from the release of RST* (external) or BOR until reset vector execution.  The section in the data sheet is usually called "Wake-up from Low Power Modes and Reset".

Jeff

Stephan Gehringer said:

has somebody experiences or has taken some measurements with the startup time from power off mode?

Startup time depends on many factors. One of them is the applicaiton itself. Since after a reset (including wakeup for power-off mode, LPM4.5 etc.), the comlete C startup sequence is executed (including variable initialization) the time until reaching the beginning of main() highly depends on the number of variables you use in your application.

Also, the current version of the bootstrap loader affects startup time, as well as the default clock speed, which varies across devices due to production tolerances.

So you have to be very specific about which exact time you mean. Too specific for a general datasheet. The only thing that yould be precisely put into the datasheet is the time from the trigger event edge to the first MCLK pulse. But this won't help you at all.

Thankyou Jeff,

but I think that doesnt fit to my problem.

I need the time from no power mode to active Mode.I think thats not really the same like external RST or?

 

Stephan

 

ok

LPM4.5 is not equal power off mode so thats not the startuptime I need.

i mean the complete startup time (power off) to the beginning of the main function. (e.g. 1 MHz with internal RC- oscillator).

 

so it doesnt help me to know the time to the first MCLK pulse.

 

Has somebody taken this measurements?

Stephan,

Hopefully somebody has taken the measurements you want.  However, you should consider the following startup sequence for a power-up event:

1. Vcc Ramp Up (driven by power supply)
2. BOR release
3. Low-Level Boot Code  (MCLK is now running.)
4. Check for Bootstrap Loader entry sequence
5. Begin executing user code at reset vector
6. C Startup (including customizations)
7. First statement of main( ).

Maybe you could be more clear about which range of these steps concerns you.  You are in total control of step 1.  Steps 2 through 5 are specified in the data sheets (2 ms typical, 3 ms max).  Step 6 takes a variable amount of time depending on customizations and amount and type of initializations required.

Jeff

Stephan Gehringer said:

i mean the complete startup time (power off) to the beginning of the main function.

And I told you that this time depends on many factors of which some are in no way under the control or knowledge of the hardware manufacturer. Including the execution time of the init code, which depends on the used compiler, the used memory model, the number of variables you use and more.

There is no definitive answer to this question. It's as as impossible to answer as it is impossible to give an answer to the question "when will I die?"
Well, I can narrow it down: either less than the default WDT timeout period or eternal. Every change in your program may change this time.

Jeff Tenney said:

Stephan,

Hopefully somebody has taken the measurements you want.  However, you should consider the following startup sequence for a power-up event:

1. Vcc Ramp Up (driven by power supply)
2. BOR release
3. Low-Level Boot Code  (MCLK is now running.)
4. Check for Bootstrap Loader entry sequence
5. Begin executing user code at reset vector
6. C Startup (including customizations)
7. First statement of main( ).

Maybe you could be more clear about which range of these steps concerns you.  You are in total control of step 1.  Steps 2 through 5 are specified in the data sheets (2 ms typical, 3 ms max).  Step 6 takes a variable amount of time depending on customizations and amount and type of initializations required.

Jeff

 

 

Thankyou Jeff,

I think i can life with this answer.

so:

from step one to five I need max. 3 ms.

and if I understand you correctly

Step 6 is the time of initialisasations I have to make. e.g. declaring Pins as output pins etc.

so in step 6 the cpu is running in active mode and i can calculate the time by multiplying the clockfrequency with my number of orders. (is there no approximate value with a minimal configuration?)

 

 

Thankyou