if condition for modules? (verilog question)

Altera_Forum · ‎09-05-2009

Hello there!

I don't know if this is a simple question or not. Basically I want to switch view of my lcd panel input from software and hardware (camera input) by using a switch.

The thing is, i want to switch the use of modules with an if statement, but it doesn't seem to work like that:

always @ (posedge iCLK_50)

begin

if(iSW[1])

begin

touch_panel tp1 ( //<---module declaration

.iCLK(ltm_nclk),

.iRST_n(DLY_RST_2),

// sdram side

.iREAD_DATA1(Read_DATA1),

.iREAD_DATA2(Read_DATA2),

.oREAD_SDRAM_EN(Read),

// lcd side

.oLCD_R(ltm_r),

.oLCD_G(ltm_g),

.oLCD_B(ltm_b),

.oHD(ltm_hd),

.oVD(ltm_vd),

.oDEN(ltm_den)

);

end

else

begin

//different module for touch panel

end

so this definitely doesn't work. Any tips on how to implement this?

Thanks in advance!!!!

Altera_Forum · ‎09-05-2009

Hi ayhoung,

verilog does not allow to instanciate a module (here touch_panel) based on the value of a signal (here iSW[1]).

--- Quote Start ---

always @ (posedge iCLK_50)

begin

if(iSW[1])

begin

touch_panel tp1 ( //<---module declaration

.iCLK(ltm_nclk),

--- Quote End ---

In real hardware it would mean that depending a logic input signal on a printed circuit board you would magically add (or remove) an integrated circuit component.

You can however use a multiplexer to select these signals that you want to enter to another module.

e.g.

 
if (iSW) begin
  lcd_R = camera1_buffer_R;
  lcd_G = camera1_buffer_G;
  lcd_B = camera1_buffer_B;
end else begin
  lcd_R = camera2_buffer_R;
  lcd_G = camera2_buffer_G;
  lcd_B = camera2_buffer_B;
end

When working with video signals you should of course be careful that the signals you are connecting are compatible in format and timing. Otherwise this will not work.

Hope this helps...

Altera_Forum · ‎09-05-2009

Thanks I will try that out :)