Solder Jumper Alternative

[AtomSoft]

Ok i have a potential issue on my hands. I have a 24 SIGNALS cut into groups of 3.
Lets call them A, B , C... which have 8 signals each

I want to be able to use each separately at one point then have the option to combine them... so my circuit can be

A0 ---------- ITS OWN LINE
A1 ---------- ITS OWN LINE
..
A6 ---------- ITS OWN LINE
A7 ---------- ITS OWN LINE

B0 ---------- ITS OWN LINE
B1 ---------- ITS OWN LINE
..
B6 ---------- ITS OWN LINE
B7 ---------- ITS OWN LINE

C0 ---------- ITS OWN LINE
C1 ---------- ITS OWN LINE
..
C6 ---------- ITS OWN LINE
C7 ---------- ITS OWN LINE

And either i use a solder jumper to connect each like:

A0 - A7 = 1 SIGNAL LINE
B0 - B7 = 1 SIGNAL LINE
C0 - C7 = 1 SIGNAL LINE

to make only 3 signal lines...

But then if i want to have all 24 lines separate again i would have to desolder them all.. how can i do this digitally ? The max voltage on each line will be 3.3v i doubt it will use much current at all. Its just normal signal pins.

So basically i want to be able to switch from having 24 DATA LINES to 3 DATA LINES and back and forth... without having to solder and desolder or having BULKY HEADERS...

Any ideas? perhaps like some digital switch i can use to connect them?...

Thanks in advance

 

[crutschow]

A digital switch, such as a 4016 or 4066 quad bilateral switch between each input would work.

 

[AtomSoft]

Might take up too much space but that gave me a cool idea...

http://search.digikey.com/us/en/products/XC9572XL-10VQG64C/122-1388-ND/826991
This is 64-pin VQFP (52 user I/O pins)

This way i can make 24 input and 24 output. And 1 pin for merge.

If MergePin is set when Clock pin in clocked then
{
    //A0 goes to all the A port OUTPUTS
    INPUT AI0 goes to AO0
    INPUT AI0 goes to AO1
    INPUT AI0 goes to AO2
    INPUT AI0 goes to AO3
    INPUT AI0 goes to AO4
    INPUT AI0 goes to AO5
    INPUT AI0 goes to AO6
    INPUT AI0 goes to AO7
}
else
{
    //A0:A7 INPUTS to A0-A7 OUTPUTS (Respectively)
    INPUT AI0 goes to AO0
    INPUT AI1 goes to AO1
    INPUT AI2 goes to AO2
    INPUT AI3 goes to AO3
    INPUT AI4 goes to AO4
    INPUT AI5 goes to AO5
    INPUT AI6 goes to AO6
    INPUT AI7 goes to AO7
}

and etc for B and C INPUTS and OUTPUT...

Code would be something like that. Since its a FPGA i can remap the pins to make tracing it easier and its under $3 and takes up little space which is cool!
Its fast also! System frequency up to 178 MHz !

Only issue is its a 3.3v part but not really a issue for what i need but if i wanted to make a similar 5v version it would suck but it will have to do

 

[AtomSoft]

Correction:

The I/Os on each XC9500XL device are fully 5V tolerant
even though the core power supply is 3.3 volts. This allows
5V CMOS signals to connect directly to the XC9500XL
inputs without damage.

NICE!

 

[RichTheDude]

I was going to say stick a CPLD on your board

 

[AtomSoft]

Yeah heh now i need to order some.. Also need a simple way to program them.. Tqft adapters cost too much

 

[3v0]

Some of the newer PIC 18F's and 24F's have a 2nd set of peripherals that can be assigned to a subset of the pins. Not sure what the application is so I have no idea if that would work for you.

 

[RichTheDude]

The CPLD has in system programming via JTAG. Wire up the JTAG pins to a socket on the PCB and it's job done .

TQFP sockets are really really expensive. Whenever I see a scrap board with one on it, I ensure I purloin it!