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John Murphy wrote:
> Do I need to implement software to catch and
hide this wrap assuming
> periodic execution at high enough rate to see the wrap, or does EMC have > some way of handling this. Following function "expands" a 16 bit hardware
counter to a 32bit long.
What we do here is just measure the displacement
that the counter has count (wich can be positive or negative) between two
succesive reads and add this to a long variable. The counter may not exceed
65536 / 2 counterpulses between 2 reads.
I use this short routine for expanding a 8 bit
counter...
long Counter; // global variable
counter
void Count(void)
{ int HwCounter, Displacement; ActualCounter = ReadHardwareCounter(); Displacement = ActualCounter - PreviousCounter; Counter + (long)Displacement PrevCounter = Counter; } Luc |