Combining 4 nibble to 16bits

[HenrikOlsson]

Hi,
Perhaps something like this:

Result var word

'Nibble 1 is the 4 most significant bits, Nibble4 the 4 least significant.
'Most signinficant bit in nibble 1 is most significant bit in result.
Result = (Nibble1 * 4096) + (Nibble2*256) + (Nibble3 * 16) + Nibble4

Nibble1----Nibble2---Nibble3--Nibble4
0 0 1 0 - 1 1 0 0 - 0 0 0 1 - 1 1 1 0 = 11294(dec)

(2*4096)+(12*256)+(1*16)+14 = 11294

/Henrik Olsson.

[sayzer]

Hi Isaac,

It would be more helpful if you could explain what you need in more detail.

As much as I understood, reading the port pins individually could work for you.

Nibbles are BITs, not bytes.

nibble1 = PORTD.0
nibble2 = PORTD.1
nibble3 = PORTD.2
nibble4 = PORTD.3

Then you can take these four bits and use as you like.


Or am I on the wrong track here?


--------------------

[SteveB]

From what you have explained, here is something that should work:

Full_Word var Word
Low_Byte  var Full_Word.lowbyte
High_Byte Var Full_Word.Highbyte

'First Nibble
High_Byte = (PortD & %00001111)
High_Byte = High_Byte << 4
'Second Nibble
High_Byte = High_Byte + (PortD & %00001111)
'Third Nibble
Low_Byte = (PortD & %00001111)
Low_Byte = Low_Byte << 4
'Forth Nibble
Low_Byte = Low_Byte + (PortD & %00001111)
'Full_Word now has the 16 bit result of 4 Nibbles

HTH,
Steve

[i]EDIT: just changed port, since I miss read original post and used B instead of D

[isaac]

Sorry sayzer

if i didn't give enough explaination so here it is

I have 4 variables of 4bits each
Nibble1,Nibble2,Nibble3 and Nibble4
Lets assume that they contain the following values

nibble1=F which is binary 1111
nibble2=E which is binary 1110
nibble3=D which is binary 1101
nibble4=C which is binary 1100

i want to combine them to form a 16bit word variable say result
to make result=FEDC or 1111111011011100

Then i can use the shiftout command to send the value of result
as

ShiftOut DataP,Clk,MsbFirst,[result\16]

instead of as below as i presently do it

ShiftOut DataP,Clk,MsbFirst,[nibble1\4,nibble2\4,nibble3\4,nibble4\4]

Those are read in on PORTD.0 - PORTD3 one at a time as the device
i am reading is only capable of send 4bits at a time.
i think SteveB method might work though


Hope this is clear
Isaac