triangle

src/apu/mod.rs

@@ -152,7 +152,8 @@ impl Apu {
         }
         if (self.current_frame == 1)
             || (self.frame_counter == 4 && self.current_frame == 3)
-            || (self.frame_counter == 5 && self.current_frame == 4) {
+            || (self.frame_counter == 5 && self.current_frame == 4)
+        {
             // step length counters and sweep units
             self.square1.clock_sweep();
             self.square2.clock_sweep();

src/apu/square.rs

@@ -200,7 +200,6 @@ impl Square {
         // When the enabled bit is cleared (via $4015), the length counter is forced to 0 and cannot be changed until enabled is set again (the length counter's previous value is lost).
         if self.enabled {
             self.length_counter = super::LENGTH_COUNTER_TABLE[value as usize >> 3];
-            // println!("val: 0b{:08b}, wrote length_counter {}", value, self.length_counter);
         }
         let timer_high = value as u16 & 0b0000_0111;
         self.timer_period &= 0b11111000_11111111; // mask off high 3 bits of 11-bit timer

src/apu/triangle.rs

@@ -1,37 +1,30 @@
-
-// $4008 	Hlll.llll 	Triangle channel length counter halt and linear counter load (write)
-// bit 7 	H--- ---- 	Halt length counter (this bit is also the linear counter's control flag) 
 pub struct Triangle {
-    pub sample: u16,
-    timer: usize,
-    pub length_counter: usize, // (this bit is also the linear counter's control flag) 
-    linear_counter: usize,
     pub enabled: bool,
+    pub sample: u16,
+
+    timer: u16,
+    timer_period: u16,
+    
+    pub length_counter: usize,
+    length_counter_halt: false, // (this bit is also the linear counter's control flag) / (this bit is also the length counter halt flag)
+    
+    linear_counter: usize,
 }
 
 impl Triangle {
     pub fn new() -> Self {
         Triangle {
-            timer: 0,
-            length_counter: 0,
-            linear_counter: 0,
-            sample: 0,
             enabled: false,
+            sample: 0,
+            timer: 0,
+            timer_period: 0,
+            length_counter: 0,
+            length_counter_halt: false,
+            linear_counter: 0,
+            linear_counter_reload: false,
         }
     }
 
-    pub fn write_timer_low(&mut self, value: u8) {
-
-    }
-
-    pub fn write_timer_high(&mut self, value: u8) {
-        
-    }
-
-    pub fn write_counter(&mut self, value: u8) {
-        
-    }
-
     pub fn clock(&mut self) {
         
     }
@@ -43,4 +36,28 @@ impl Triangle {
     pub fn clock_length_counter(&mut self) {
         
     }
+
+    // $4008
+    pub fn write_counter(&mut self, value: u8) {
+        self.length_counter_halt = value >> 7 as bool;
+        self.counter_reload_value = (value << 1) >> 1;
+    }
+
+    // $400A
+    pub fn write_timer_low(&mut self, value: u8) {
+        self.timer_period &= 0b00000111_00000000;
+        self.timer_period |= value;
+    }
+
+    // $400B
+    pub fn write_timer_high(&mut self, value: u8) {
+        if self.enabled {
+            self.length_counter = super::LENGTH_COUNTER_TABLE[value as usize >> 3];
+        }
+        self.timer_period &= 0b00000000_11111111;
+        let timer_high = value & 0b0000_0111;
+        self.timer_period |= timer_high << 8;
+        self.linear_counter_reload = true;
+    }
+
 }