FRO AND RRO USING HEXADECIMAL SWITCH

[AmitKumar171]

Hi Tom,

I am using KFLOP+KONNECT+KANALOG for connecting FRO i.e. the Hexadecimal switch which has 5 input pins and 16 position based on the 5 input pins.

I have connected the all 5 input pins for Hexadecimal switch to konnect pin number 1040,1041,1042,1043,1044. I want to set each position out of 16 position to use FRO 0 to 1.6.

How to proceed with the programs for checking 5 pins at each FRO change. ? how can i check the 5 pins for one input of FRO.

Waiting for your kind reply.

[TomKerekes]

Hi Amit,

A hexadecimal switch should normally require 4 bits not 5.

Does the switch return gray code or binary?

If gray code you might do something like:

Code: Select all

#include "KMotionDef.h"

int grayToBinary(int num)
{
        unsigned int temp = num ^ (num>>4);
        temp ^= (temp>>2);
        temp ^= (temp>>1);
        return temp;
}

void main()
{
	float FRO=0.1f*grayToBinary(ReadBit(1040)*8+ReadBit(1041)*4+ReadBit(1042)*2+ReadBit(1043));
}

[AmitKumar171]

Hi tom ,

Thanks for your reply.

A hexadecimal switch should normally require 4 bits

Yes it requires 4 bits.

Does the switch return gray code or binary?

The switch returns binary codes.

Help me with Binary code program.

Waiting for your kind reply.

[TomKerekes]

Hi Amit,

The problem with binary is sampling bits while they are changing can give indeterminate values. For example changing from 7 to 8 might temporarily read 0 or 15. I think the same debounce function can be used to identify when things have changed and are stable. See below:

Code: Select all

#include "KMotionDef.h"

int hlast=0,hlastsolid=-1,hcount=0;
int Debounce(int n, int *cnt, int *last, int *lastsolid);

void main()
{
	int hex;
	float FRO;
	
	for(;;)
	{
		WaitNextTimeSlice();

		// read hex value with potential glitches
		hex = ReadBit(1040)*8+ReadBit(1041)*4+ReadBit(1042)*2+ReadBit(1043);
		
		// "debounce" hex value
		if (Debounce(hex,&hcount,&hlast,&hlastsolid)!=-1) // changed and stable?
		{ 
			FRO = hlast * 0.1f;
			printf("FRO changed to %f\n",FRO);
		}
	}
}


// Debounce a bit
//
// return 1 one time when first debounced high 
// return 0 one time when first debounced low 
// return -1 otherwise 
#define DBTIME 300

int Debounce(int n, int *cnt, int *last, int *lastsolid)
{
	int v = -1;
	
	if (n == *last)  // same as last time?
	{
		if (*cnt == DBTIME-1)
		{
			if (n != *lastsolid)
			{
				v = *lastsolid = n;  // return debounced value
			}
		}
		if (*cnt < DBTIME)	(*cnt)++;
	}
	else
	{
		*cnt = 0;  // reset count
	}
	*last = n;
	return v;
}

[AmitKumar171]

Hi tom,

THanks for your reply, will check that and update.