avr-something

commit b16c6796f167e253997ec3aea8d925553cffe9e1
parent c3ff610aec4705de6bf1906171591f2572f2e32a
Author: Henry Wilson <m3henry@googlemail.com>
Date:   Fri, 16 Feb 2018 11:59:02 +0000

Stereo 8-bit sine wave sound generation

Externally swapped pins D[5,6]

Diffstat:
M
hidModule.h
 | 
2
+-
M
main.cpp
 | 
69
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++----------
M
utils.h
 | 
24
+++++++++++++++++++++++-

3 files changed, 83 insertions(+), 12 deletions(-)
diff --git a/hidModule.h b/hidModule.h
@@ -53,7 +53,7 @@ constexpr auto buttonD = bit(6);
 
 constexpr auto ledRED = bit(7);
 constexpr auto ledYEL = bit(4);
-constexpr auto ledGRN = bit(6);
+constexpr auto ledGRN = bit(5);
 
 void init();
 
diff --git a/main.cpp b/main.cpp
@@ -2,6 +2,7 @@
 #include "lcd.h"
 #include "ctrl.h"
 
+#include <avr/interrupt.h>
 #include <util/delay.h>
 
 namespace timer
@@ -44,10 +45,30 @@ auto& outputCompareB()
 {
 	return memory(0xB4);
 }
+auto& interruptMask()
+{
+	return memory(0x70);
+}
+auto const& interruptFlags()
+{
+	return memory(0x37);
+}
 }
 
 }
 
+uint8_t const sinTable[] [[gnu::progmem]] =
+{
+	0,	3,	6,	9,	12,	16,	19,	22,
+	25,	28,	31,	34,	37,	40,	43,	46,
+	49,	51,	54,	57,	60,	63,	65,	68,
+	71,	73,	76,	78,	81,	83,	85,	88,
+	90,	92,	94,	96,	98,	100,102,104,
+	106,107,109,111,112,113,115,116,
+	117,118,120,121,122,122,123,124,
+	125,125,126,126,126,127,127,127
+};
+
 int main(void) 
 {
 	ctrl::disableJTAG();
@@ -66,18 +87,46 @@ int main(void)
 	timer::two::outputCompareA() = 0x80;
 	timer::two::outputCompareB() = 0x80;
 	timer::two::control() = 0b00'00'0'001'1111'00'11;
-	
-	uint8_t x = 0;
-	uint16_t y = 0;
+
 	for (;;)
 	{
-		timer::two::outputCompareA() = x++;
-		
-		timer::two::outputCompareB() = y-- >> 8;
-		//io::pin::D() = bit(5);
-		_delay_us(10);
-		//io::pin::D() = bits(5, 7);
-		//_delay_ms(1);
+		constexpr uint8_t midPoint = 127;
+		constexpr auto begin = flashPtr(sinTable);
+		constexpr auto end = begin + 64;
+		auto ptr = flashPtr(sinTable);
+		do
+		{
+			auto val = midPoint + ptr.load_post_inc();
+			timer::two::outputCompareA() = val;
+			timer::two::outputCompareB() = val;
+			_delay_us(10);
+		}
+		while (ptr != end);
+
+		while (ptr != begin)
+		{
+			auto val = midPoint + (--ptr).load();
+			timer::two::outputCompareA() = val;
+			timer::two::outputCompareB() = val;
+			_delay_us(10);
+		}
+
+		do
+		{
+			auto val = midPoint - ptr.load_post_inc();
+			timer::two::outputCompareA() = val;
+			timer::two::outputCompareB() = val;
+			_delay_us(10);
+		}
+		while (ptr != end);
+
+		while (ptr != begin)
+		{
+			auto val = midPoint - (--ptr).load();
+			timer::two::outputCompareA() = val;
+			timer::two::outputCompareB() = val;
+			_delay_us(10);
+		}
 	}
 
 }
diff --git a/utils.h b/utils.h
@@ -38,7 +38,7 @@ inline constexpr uint8_t mix(const uint8_t a, const uint8_t b, const uint8_t mas
 
 struct flashPtr
 {
-	inline flashPtr(uint8_t const* const p) : ptr(p) {}
+	inline constexpr flashPtr(uint8_t const* const p) : ptr(p) {}
 	inline uint8_t load() const
 	{
 		uint8_t result;
@@ -63,6 +63,28 @@ struct flashPtr
 		);
 		return result;
 	}
+	inline constexpr flashPtr& operator ++()
+	{
+		++ptr;
+		return *this;
+	}
+	inline constexpr flashPtr& operator --()
+	{
+		--ptr;
+		return *this;
+	}
+	inline constexpr flashPtr operator +(const uint16_t delta) const
+	{
+		return flashPtr(ptr + delta);
+	}
+	inline constexpr flashPtr operator -(const uint16_t delta) const
+	{
+		return flashPtr(ptr - delta);
+	}
+	inline constexpr bool operator !=(const flashPtr& that) const
+	{
+		return ptr != that.ptr;
+	}
 
 	static_assert(sizeof(uint16_t) == sizeof(uint8_t const *), "Flash ptr should be a word");