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timer 2 ,short pulses

Other Parts Discussed in Thread: LM3578A

how do I get short pulses of 140uS with the timer 2 on cc1110? does any one knows the routine?

  • This depends on your input crystal frequency.  The Timer 2 period is based on essentially 3 register values and the input clock frequency.

    Section 12.7 of the CC1110 datasheet provides information on the 3 register field values.

    • Timer tick speed (CLKCON.TICKSPD)
    • T2CTL.TIP
    • Prescaler value (T2PR)

    T = T2PR * Val(T2CTL.TIP)/timer tick speed

    T2PR         : values 1 to 256
    T2CTL.TIP : Val(00) = 64, Val(01) = 128, Val(10) = 256, Val(11) = 1024
    timer tick   : input frequency divided by one of (1, 2, 4, 8, 16, 32, 64, 128)


    For example, if the input clock frequency is 26MHz, the following would result into something close to 140usec (actually 138usec).
    T2PR = 28
    T2CTL.TIP = 00b or 64

  • Im looking for a step-up converter that must cope with a SoC1110 to built EMS(electrical muscle stimulation)Requires the stimulation current to penetrate the resistance of the skin and the electrode,about 1500ohm.and maintain a current of up to 30mA(maybe 60ma)short pulses of 160mS 2HZ,asymmetrical biphasic pulse,100%compensated,feeding with a 3.3V cell Vin,maybe getting 45V output,really is not a problem the slow start,because as you see I have 499mS between the pulses!but what is really important is:
    -the small size of the components(as small as posible)
    -the wave caracteristics:reach 160uS on 2-3uS well the perfect asymmetrical biphasic pulse 100%compensated.
    what are my options?boost,buckboost,cuk,charge-pump(interesting way 4 transistor mosf and a condensator,and time for charging)or isolated flyback or forward types? I need some advise

  • It appears you have another thread going on this subject, which has a response.  I will defer to that thread.

    It appears these items are potentially related, unless the information regarding the timer 2 short pulses does not provide the functionality you are looking for.

  • thanks
    given the 26mhz clock cc1110-2510
    T2PR = 28
    T2CTL.TIP = 00b or 64

    the routine ensure 138uS pulses?,but I need only 2 pulses,and perhaps maybe only one( 1hz)30-60mA to overpass the skin resistance 1500ohm,reaching80%of the total output current in 2-3uS(fisiologicaly tested)from 3.3V batery.well this is the pulse..and after that,the hole system will disconect ,finish .I will ensure remote conntrol of  EMS(electricall-muscle-stimulation)devises(299eur wired).they are limited because of the wires to small areas,at once.I will improve a hole connected system,syncronized,when never 2 devises will work at the same time of course.the main control change the current and the frecuencie of the pulse(pulses)I have 499ms between pulses!time for SoC link,avoiding EMI problems.pulse generator,(a boost)few examples,from TexasInstrument the converters TPS61 series,from NationalSemiconductors LM3578A,fromLinearPower theLTC1871,LTC1619,LT3495.The problems is that doing it all in a single boost stage would be very difficult and I doubt the control loop could be fast enough to accurately produce the  waveform shape I need (4-6ms 32steps slowstart and so on)it must be done once the loop are ready ,"swithing fast in old fashion"the output.creating routines that change the pwm widht between 138-260uS at the same current of 60mA,45v,regulating the power stimulation signal
    From your software perspective,how difficult is it for one single node?(without the hole protocol,of 16nodes,16 muscles,just only for one)