Adding documentation for VGA module and testbench

Author: ErickOF

modules/vga/src/vga_tb.cpp

@@ -2,8 +2,10 @@
 
 #include "vga.hpp"
 
-// 120 MHz
+
+// Main clock frequency in Hz - 120 MHz
 #define CLK_FREQ 120000000
+// VGA settings
 #define H_ACTIVE 640
 #define H_FP 16
 #define H_SYNC_PULSE 96
@@ -12,41 +14,46 @@
 #define V_FP 10
 #define V_SYNC_PULSE 2
 #define V_BP 33
+// Compute the total number of pixels
 #define TOTAL_PIXELES ((H_ACTIVE + H_FP + H_SYNC_PULSE + H_BP) *\
                        (V_ACTIVE + V_FP + V_SYNC_PULSE + V_BP))
 
 
 int sc_main(int, char*[])
 {
+  // Compute the clock time in seconds
   const double CLK_TIME = 1.0 / static_cast<double>(CLK_FREQ);
+  // Compute the total simulation based on the total amount of pixels in the
+  // screen
   const double SIM_TIME = CLK_TIME * static_cast<double>(TOTAL_PIXELES);
 
-  sc_time total_sim_time = sc_time(SIM_TIME, SC_SEC);
-
-  sc_core::sc_clock s_clk("clk", CLK_TIME, sc_core::SC_SEC);
+  // Signals to use
+  sc_core::sc_clock clk("clk", CLK_TIME, sc_core::SC_SEC);
   sc_core::sc_signal<bool> s_hsync;
   sc_core::sc_signal<bool> s_vsync;
-
 #ifdef IPS_DEBUG_EN
   sc_core::sc_signal<int> s_h_count;
   sc_core::sc_signal<int> s_v_count;
 #endif // IPS_DEBUG_EN
 
+  // VGA module instanciation and connections
   vga<
     H_ACTIVE, H_FP, H_SYNC_PULSE, H_BP,
     V_ACTIVE, V_FP, V_SYNC_PULSE, V_BP
   > ips_vga("ips_vga");
-  ips_vga.clk(s_clk);
+  ips_vga.clk(clk);
   ips_vga.o_hsync(s_hsync);
   ips_vga.o_vsync(s_vsync);
 #ifdef IPS_DEBUG_EN
   ips_vga.o_h_count(s_h_count);
   ips_vga.o_v_count(s_v_count);
 #endif // IPS_DEBUG_EN
 
+  // Signals to dump
 #ifdef IPS_DUMP_EN
   sca_util::sca_trace_file* tf = sca_util::sca_create_vcd_trace_file("ips_vga");
-  sca_trace(tf, s_clk, "clk");
+
+  sca_trace(tf, clk, "clk");
   sca_trace(tf, s_hsync, "hsync");
   sca_trace(tf, s_vsync, "vsync");
 #ifdef IPS_DEBUG_EN
@@ -55,11 +62,12 @@ int sc_main(int, char*[])
 #endif // IPS_DEBUG_EN
 #endif // IPS_DUMP_EN
 
+  // Start time
   std::cout << "@" << sc_time_stamp() << std::endl;
-  std::cout << "Expected total sim time: " << total_sim_time << std::endl;
 
   sc_start(SIM_TIME, sc_core::SC_SEC);
 
+  // End time
   std::cout << "@" << sc_time_stamp() << std::endl;
 
 #ifdef IPS_DUMP_EN