timestamping data

Hello, 
 
Im using an HCS12 MCU interfaced with an E-field sensor and a 300ksps ADC
inorder to record the electric field coming from an EMP bomb. the
phenomenon will only last a few milliseconds, maybe microseconds and i want
to timestamp the data, which will then be processed in matlab to display
magnitude versus time plots. Can anyone point me in the right direction on
data timestamping w/ an MCU?..My MCU is configured to operate with a bus
speed of 30MHZ. 

	   
					
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"PecosBill" <gunclub84@n_o_s_p_a_m.gmail.com> wrote in message 
news:M-idneBkp4zX3dXQnZ2dnUVZ_vCdnZ2d@giganews.com...
> Hello,
>
> Im using an HCS12 MCU interfaced with an E-field sensor and a 300ksps ADC
> inorder to record the electric field coming from an EMP bomb. the
> phenomenon will only last a few milliseconds, maybe microseconds and i 
> want
> to timestamp the data, which will then be processed in matlab to display
> magnitude versus time plots. Can anyone point me in the right direction on
> data timestamping w/ an MCU?..My MCU is configured to operate with a bus
> speed of 30MHZ.
>
>
>
> --------------------------------------- 
> Posted through http://www.EmbeddedRelated.com

Just use the internal free running counter as your timestamp having set it 
up to prescale of 1.

Depending on your interface method to your ACD, either timer capture the 
timestamp or just read the time counter when the ADC data is ready.

Which HCS12 device are you using to be able to run at 30MHz?
Most are limited to 25MHz bus speed.

PhilW