register int x;
			  register int y;
			  register int z;
			  register unsigned char k;
			  cycle_sample_count[0] += 128;
			  cycle_sample_count[1] += 128;
			  cycle_sample_count[2] += 128;

			for(check1=0;check1<1;check1++)
			{
		       if (abs(V_Act[check1] - last_V_sample[check1]) <= since_last * MAX_PER_SAMPLE_VOLTAGE_SLEW)
				 {
				    /* This doesn't look like a spike - do mains cycle detection, and
				  		estimate the precise mains period */
				  	if (V_Act[check1] < 0)
				  	  {
				  		/* Log the sign of the signal */
				  		 p_status[check1] &= ~V_POS;
				  	   }
				    else
				  	   {
				  		if (!(p_status[check1] & V_POS))
				  		  {
				  			/* Apply limits to the sample count, to avoid spikes or dying power lines disturbing the
				  			  frequency reading too much */
				  			 /* The mains should be <40Hz or >70Hz to fail this test! */
				  			  if (128*SAMPLES_PER_10_SECONDS/700 <= cycle_sample_count[check1]  &&  cycle_sample_count[check1] <= 128*SAMPLES_PER_10_SECONDS/400)
				  			    {
				  			        /* A mains frequency measurement procedure based on interpolating zero crossings,
				  			           to get a fast update rate for step changes in the mains frequency */
				  			         /* Interpolate the zero crossing by successive approx. */
				  			          z = V_Act[check1] - last_V_sample[check1];
				  			          x = 0;
				  			          y = 0;
				  			        for (k = 0;  k < 8;  k++)
				  			         {
				  			            y <<= 1;
				  			            z >>= 1;
				  			            x += z;
				  			           if (x > V_Act[check1])
				  			              x -= z;
				  			           else
				  			              y |= 1;
				  			           }
				  			              /* Now we need to allow for skipped samples, due to spike detection */
				  			              z = y;
				  			             while (since_last > 1)
				  			               {
				  			                  z += y;
				  			                  since_last--;
				  			                }
				  			               /* z is now the fraction of a sample interval between the zero
				  			               crossing and the current sample, in units of 1/256 of a sample */
				  			               /* A lightly damped filter should now be enough to remove noise and get a
				  			               stable value for the frequency */
				  			               mains_period[check1] += ((int32_t) (cycle_sample_count[check1] - z) << 12) - (mains_period[check1] >> 4);
				  			                      /* Start the next cycle with the residual fraction of a sample */
				  			               cycle_sample_count[check1] = z;
				  			             }
				  			         else
				  			             {
				  			                 cycle_sample_count[check1] = 0;
				  			              }

				  			       }
				  			            /* Log the sign of the signal */
				  			      p_status[check1] |= V_POS;
				  			   }
				  			since_last = 0;
				  			last_V_sample[check1] = V_Act[check1];
				  	     }
				  	since_last++;
			}

			Idle_Sample_Count++;
		}
}