// Copyright lowRISC contributors.
// Licensed under the Apache License, Version 2.0, see LICENSE for details.
// SPDX-License-Identifier: Apache-2.0

module pwm_chan (
  input        clk_i,
  input        rst_ni,

  input        pwm_en_i,
  input        invert_i,
  input        blink_en_i,
  input        htbt_en_i,
  input [15:0] phase_delay_i,
  input [15:0] duty_cycle_a_i,
  input [15:0] duty_cycle_b_i,
  input [15:0] blink_param_x_i,
  input [15:0] blink_param_y_i,

  input [15:0] phase_ctr_i,
  input        cycle_end_i,
  input        clr_blink_cntr_i,

  output logic pwm_o
);

  // TODO: This block is currently incomplete, so doesn't use several of its input signals. These
  //       are waived in pwm.vlt. When implementing the block, delete the waivers there.

   logic [15:0] duty_cycle_actual;
   logic [15:0] on_phase;
   logic [15:0] off_phase;
   logic        phase_wrap;
   logic        pwm_int;

   // TODO: Implement blink modes
   assign duty_cycle_actual = duty_cycle_a_i;

   assign on_phase = phase_delay_i;
   assign {phase_wrap, off_phase} = {1'b0, phase_delay_i} + {1'b0, duty_cycle_actual};

   logic on_phase_exceeded;
   logic off_phase_exceeded;

   assign on_phase_exceeded  = (phase_ctr_i >= on_phase);
   assign off_phase_exceeded = (phase_ctr_i >= off_phase);


   assign pwm_int = pwm_en_i   ? 1'b0 :
                    phase_wrap ? on_phase_exceeded | ~off_phase_exceeded :
                                 on_phase_exceeded & ~off_phase_exceeded;

   assign pwm_o = invert_i ? ~pwm_int : pwm_int;

endmodule : pwm_chan