From 85b407fa65a3adf80f6248328006724395e0b4bc Mon Sep 17 00:00:00 2001
From: xeovalyte <me+gitea@xeovalyte.dev>
Date: Mon, 10 Feb 2025 15:16:23 +0100
Subject: [PATCH] Added counter

---
 .gitignore          |  5 +++++
 README.md           | 12 ++++++++++++
 ch4/timebase.sv     | 11 +++++++----
 ch4/timebase.sv.bak |  5 -----
 ch4/timebase_tb.sv  | 10 +++++++---
 devenv.nix          | 11 -----------
 6 files changed, 31 insertions(+), 23 deletions(-)
 create mode 100644 README.md
 delete mode 100644 ch4/timebase.sv.bak

diff --git a/.gitignore b/.gitignore
index 4d058db..4f52289 100644
--- a/.gitignore
+++ b/.gitignore
@@ -5,5 +5,10 @@ devenv.local.nix
 # direnv
 .direnv
 
+*.bak
+obj_dir
+output.vcd
+
+
 # pre-commit
 .pre-commit-config.yaml
diff --git a/README.md b/README.md
new file mode 100644
index 0000000..72145be
--- /dev/null
+++ b/README.md
@@ -0,0 +1,12 @@
+# DSB course
+
+## Chapter 4
+
+Minimum number for counter:
+$$
+N(t_{PWM}) = t_{PWM} * f
+$$
+Number of required bits:
+$$
+N = ^2log(N + 1)
+$$
diff --git a/ch4/timebase.sv b/ch4/timebase.sv
index d04bc37..57a8ab1 100644
--- a/ch4/timebase.sv
+++ b/ch4/timebase.sv
@@ -1,8 +1,11 @@
-module timebase 
+`timescale 1ns/1ps
+
+module timebase #(parameter N = 18) 
    (input logic clk,
     input logic reset,
-    output logic [?:0] count);
-
-
+    output logic [N-1:0] count);
 
+  always_ff @(posedge clk, posedge reset)
+    if(reset) count <= 0;
+    else count <= count + 1;
 endmodule
diff --git a/ch4/timebase.sv.bak b/ch4/timebase.sv.bak
deleted file mode 100644
index 219e656..0000000
--- a/ch4/timebase.sv.bak
+++ /dev/null
@@ -1,5 +0,0 @@
-`timescale 1ns/1ps
-
-Aanpassing van lasse
-
-Aanpassing van Timo
diff --git a/ch4/timebase_tb.sv b/ch4/timebase_tb.sv
index 0e374f4..70d8f03 100644
--- a/ch4/timebase_tb.sv
+++ b/ch4/timebase_tb.sv
@@ -4,7 +4,7 @@ module timebase_tb();
 
    logic clk;
    logic reset;
-   logic [20:0] count;
+   logic [17:0] count;
    
    timebase test (clk, reset, count);
 
@@ -14,8 +14,12 @@ module timebase_tb();
       clk = 0;
 
    initial begin
-          reset = 1; 
-     #10; reset = 0; 
+      $dumpfile("output.vcd");
+      $dumpvars;
+   
+          reset = 0; 
+     #200; reset = 1; 
+      $finish;
    end
 
 endmodule
diff --git a/devenv.nix b/devenv.nix
index fe01561..71c391f 100644
--- a/devenv.nix
+++ b/devenv.nix
@@ -1,22 +1,11 @@
 { pkgs, lib, config, inputs, ... }:
 
 {
-  # https://devenv.sh/basics/
   env.GREET = "devenv";
 
   # https://devenv.sh/packages/
   packages = [ pkgs.verilator pkgs.gtkwave ];
 
-  # https://devenv.sh/languages/
-  # languages.rust.enable = true;
-
-  # https://devenv.sh/processes/
-  # processes.cargo-watch.exec = "cargo-watch";
-
-  # https://devenv.sh/services/
-  # services.postgres.enable = true;
-
-  # https://devenv.sh/scripts/
   scripts.hello.exec = ''
     echo hello from $GREET
   '';