Regards on nexys 2 spartan 3 fpga board

[jianhuachews]

Hi guys i noticed my board has Four 12-pin Pmod (peripheral module) connectors. I am trying to interface it with my 4x4 keyboard which has a total of 8 pins (4 inputs, 4 outputs). Can i just directly connect them?



edit-
ok i realised i need to use just 8 out of the 12pin from the nexys 2 pmod connectors. but i couldn't find any datasheet on which pins i should use!! (as in like.. is it restricted to certain pins are for input, certain pins are for output and etc) anyone help?

 

[mrflibble]

Did you check the user manual + schematic for the nexys2? Digilent has those on their website...

Those 4 PMOD's can be used for input/output, depending on how you configure them. The only restriction I recall is that LD7:LD4 are shared with one of the PMOD's. But in practice that's not much of an issue.

Your 4x4 keyboard doesn't need any supply? If so, then you'd need 10 connections, 8 for the data and 2 for the 2 times ground. Or 9 connections if you want to economize.

Mainly it is just a matter of read the user manual to see how things are connected on the nexys2. And in case of doubt you can read the schematics, but for something like this the user manual should be enough...

 

[jianhuachews]

Hi mrflibble i've found that there are 8 pins on the nexys2 board that are used for i/o and 2 for power supply and another 2 for ground. But what im confused is the part where you mentioned "8 for the data and 2 for the 2 times ground." I actually have 9 connections, 8 for i/o and 1 for vcc as i have my rows of the 4x4 keypad connected to pull-up resistors (resistors to vcc) for scanning purposes.

Do i have to ground them?!

Also, may i know what is the ucf file for..? I don't understand it!
it goes something like

# 12 pin connectors

#NET "JA<0>" LOC = "L15"; # Bank = 1, Pin name = IO_L09N_1/A11, Type = DUAL, Sch name = JA1

#NET "JA<1>" LOC = "K12"; # Bank = 1, Pin name = IO_L11N_1/A9/RHCLK1, Type = RHCLK/DUAL, Sch name = JA2

So i assume that im reading the part on 12PMOD connectors, while L15 and K12 refers to some connection names in the board. But i couldn't find any L15 and K12 on my board!!

 

[mrflibble]

Possibly I am confusing you by my devilishly creative use of language. Sorry.

All I mean is that for any physical hardware that you are going to connect to the PMOD connector, you will probably have 10 connections. Not 9.

Your 8 data connections, 1 for ground, and one for vcc. But that is just a generic remark, and mainly because I do not know the details of your highly unspecified 4x4 keypad.

Do i have to ground them?!

You probably have to connect vcc as you suggest, but not sure. What does the keyboard documentation say?

 

[jianhuachews]

Hi. I was thinking about what you mentioned on the "2 times ground. "

With reference to the figure23 in pg 15 of
https://docs.google.com/viewer?a=v&pid=gmail&attid=0.1&thid=130b13adee8942d4&mt=application/pdf&url=https://mail.google.com/mail/?ui%3D2%26ik%3D133cd902f0%26view%3Datt%26th%3D130b13adee8942d4%26attid%3D0.1%26disp%3Dsafe%26zw&sig=AHIEtbSVSsMBUqQrqEqpHNRUDLdIQsdutw&pli=1

I thinking if i should have 2 vcc OR 2 gnd cus it seems to me like they have to be both connected...

I tried downloading the program to the xilinx nexys 2 board to test my keypad. But funny thing is, the row of my keypad, which i had them tied to resistor and connect them thru the pin 12 pmod connector (which is for the vcc), doesn't seem to be working....

ise gave me 4 warnings that shows
WARNING:iMPACT - Module windrvr6 is not loaded. Please reinstall the cable drivers. See Answer Record 22648.
WARNING:iMPACT - Module windrvr6 is not loaded. Please reinstall the cable drivers. See Answer Record 22648.
WARNING:iMPACT - Module windrvr6 is not loaded. Please reinstall the cable drivers. See Answer Record 22648.
WARNING:iMPACT - Module windrvr6 is not loaded. Please reinstall the cable drivers. See Answer Record 22648.

I suspect it's inferring to the 4 rows of my keypad which is not properly connected.

Any help please?