Counting

To use a trigger to initiate an event, check for the trigger in a block synchronized with the clock on which the trigger is operating. The triggers in okTrigger[In|Out] are active high. You do not need to instantiate a new okTrigger[In|Out] for each trigger bit, since each bit can be triggered separately using its unique FrontPanel endpoint address. In the following example, reset and count are dependent on two separate triggers located in the same instance of okTriggerIn, and are triggered separately by passing different values to the same address in ActivateTriggerIn().

The pauses in the example are included to make the LEDs readable and are not required for the triggers to operate properly.

C/C++

okCFrontPanel dev;
okCFrontPanel.ErrorCode error;
dev.OpenBySerial();
error = dev.ConfigureFPGA("example.bit");
 
// Reset the counter
dev.ActivateTriggerIn(0x41, 0);
 
for (int i=0; i<20; i++) {
     // Trigger the state machine
     dev.ActivateTriggerIn(0x41, 1);
     std::this_thread::sleep_for(std::chrono::milliseconds(100));
}Code language: PHP (php)

C#

okCFrontPanel dev = new okCFrontPanel();
okCFrontPanel.ErrorCode error = new okCFrontPanel.ErrorCode();
 
dev.OpenBySerial("");
error = dev.ConfigureFPGA("countingx.bit");
 
//Reset the counter
dev.ActivateTriggerIn(0x41, 0);
 
while(true){
     // Trigger the state machine
     dev.ActivateTriggerIn(0x41, 1);
     Thread.Sleep(1000);
}Code language: JavaScript (javascript)

Python

dev = ok.okCFrontPanel()
dev.OpenBySerial("")
error = dev.ConfigureFPGA("countingx.bit")
 
# Reset the counter
dev.ActivateTriggerIn(0x41, 0)
 
while 1 == 1:
     # Trigger the state machine
     dev.ActivateTriggerIn(0x41, 1)
     time.sleep(0.1)Code language: PHP (php)

Java

public class example{
     okCFrontPanel dev;
     okCFrontPanel.ErrorCode error;
     int i;
     Thread t;
 
     public void Initialize(){
          t = new Thread();
          dev = new okCFrontPanel();
          dev.OpenBySerial("");
          error = dev.ConfigureFPGA("countingx.bit");
          // It’s a good idea to check for errors here!
 
          // Reset the counter
          dev.ActivateTriggerIn(0x41, 0);
     }
 
     public void Count(){
          for(i = 0; i < 20; i++){
               // Trigger the state machine
               dev.ActivateTriggerIn(0x41, 1); // Count by 1
               try{ Thread.sleep(1000); }
                    catch(Exception e){ System.out.println(e); }
          }
     }
}Code language: Verilog (verilog)

Verilog

// Wire declarations
wire done;
 
// Circuit behavior	 
assign led = ~count[7:0];
	 
//set up counter
always @ (posedge clk1) begin
     if (triggers[0]) begin
          count <= 8'h00;
     end else if (triggers[1]) begin
          count <= count + 1;
     end
end
	 
// FrontPanel endpoint instantiation
okTriggerIn tcount(
     .ok1(ok1),
     .ep_addr(8'h41),
     .ep_clk(clk1),
     .ep_trigger(triggers)
);Code language: Verilog (verilog)

VHDL

--Wire declarations
signal count                   : STD_LOGIC_VECTOR(7 downto 0);
signal triggers               : STD_LOGIC_VECTOR(15 downto 0);
signal reset1                  : STD_LOGIC;
signal count_t                : STD_LOGIC;
 
-- Circuit behavior
led <= not count (7 downto 0);
reset1 <= triggers(1);
count_t <= triggers(0);
 
process(clk1) begin
     if rising_edge(clk1) then
          if (reset1 = '1') then
               count <= x"00";
          elsif (count_t = '1') then
               count <= count + '1';
          end if;
     end if;
end process;
 
-- FrontPanel endpoint instantiation
tcount : okTriggerIn
     port map(
          ok1=>ok1,
          ep_addr=>x"41",
          ep_clk=>clk1,
          ep_trigger=>triggers
     );Code language: VHDL (vhdl)