vhdl-ams:new_data_types:concurrent_statements

Concurrent Statements

Simultaneous IF and CASE Statement

    if {condition} use
         {simultaneous statement};
    [elsif {condition} use
         {simultaneous statement};]
                .
                .
                .
    [else {simultaneous statement};]
    end use;
  • appropriation like in VHDL
  • useful for piecewise defined signals
      if vin < v- use
         vout == max;
      elsif vin < v0 use
         vout == faktor_A * vin;
      elsif vin < v+ use
         vout == 0.0;
      else vout == faktor_B * vin;
      end use;

Example voltage curve 

    case {expression} use
         when {choices} use
              {simultaneous statement};
        [when {choices} use
              {simultaneous statement};]
                .
                .
                .
    end case;

Notes

If and case are used for the same appropriation like in VHDL. But at simultaneous statements the syntax differences a little.

Concurrent Break Statement

break [break_list] [on {sensitivity_clause}] [when {condition}];
sensitivity_clause ⇒ digital signals, the analog part reacts on 
     if signal = '0' use
          v == 0.0;
     else v == vmax;
     end use;
     break on signal;
  • a concurrent break statement pauses a process
  • handling like the sequential break
  • new: sensitivity_clause → digital event releases a break → start analog calculations
all simultaneous statements are concurrent; exception: simultaneous procedural statement

Notes

The concurrent break breaks a process. When a digital signal occurs a reaction at the analog part, the process is stopped, the analog changes get handled and then the process goes on. The syntax is: 

  break [break_list] [sensitivity_clause] [ when {condition}];
  sensitivity_clause := on {digital signals, that occur a reaction at the analog part}

For the break_list and the condition see at the sequential break.

Chapters of VHDL-AMS > New Data Types