///////////////////////////////////////////////////////////////////////
//
// alt_core module
//
//    this is the behavioural model of the sports altimeter without pads
//
///////////////////////////////////////////////////////////////////////

`include "options.sv"

module alt_core(

  output SegA,
  output SegB,
  output SegC,
  output SegD,
  output SegE,
  output SegF,
  output SegG,
  output DP,

  output logic [4:0] nDigit,
  
  input nMode, nTrip,

  output logic SPICLK, MOSI, nAltCS,
  input MISO,

  input Clock, nReset

  );

timeunit 1ns;
timeprecision 100ps;

// the following is behavioural (unsynthesisable) code to output P0000

assign { SegA, SegB, SegE, SegF } = '1; // always on;
assign SegC = nDigit[4]; // on when Digit[4] is inactive
assign SegD = nDigit[4]; // on when Digit[4] is inactive
assign SegG = ~nDigit[4]; // on when Digit[4] is active
assign DP = '0; // always off

always
  begin
           nDigit = 5'b11110;
    #2.5ms nDigit = 5'b11101;
    #2.5ms nDigit = 5'b11011;
    #2.5ms nDigit = 5'b10111;
    #2.5ms nDigit = 5'b01111;
    #2.5ms nDigit = 5'b01111;
  end

// this model sends a clock to the sensor
// but makes no attempt to interpret the data
// returned

always
  begin
    SPICLK = '0;
    MOSI = '0;
    nAltCS = '1;
    
    #2s nAltCS = '0;
    repeat(32)
      begin
              SPICLK = '0;
        #9ms SPICLK = '1;
        #9ms SPICLK = '0;
      end
    #9ms nAltCS = '1;
  end

endmodule