From 66dcf910bd4744d8ced56cb9586aa937a1a2d4c5 Mon Sep 17 00:00:00 2001
From: vg <vgm+dev@devys.org>
Date: Tue, 7 Jul 2020 16:24:01 +0200
Subject: first commit

---
 instructables/cube8/main.c | 285 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 285 insertions(+)
 create mode 100644 instructables/cube8/main.c

(limited to 'instructables/cube8/main.c')

diff --git a/instructables/cube8/main.c b/instructables/cube8/main.c
new file mode 100644
index 0000000..be31861
--- /dev/null
+++ b/instructables/cube8/main.c
@@ -0,0 +1,285 @@
+/*
+ * Code to controll an 8x8x8 ledcube using avr
+ * http://www.instructables.com/id/Led-Cube-8x8x8/
+ * See lisence.txt for lisence.
+ */
+#include "main.h"
+#include "effect.h"
+#include "launch_effect.h"
+#include "draw.h"
+
+// Main loop
+// the AVR enters this function at boot time
+int main (void)
+{
+
+	// This function initiates IO ports, timers, interrupts and
+    // serial communications
+	ioinit();
+	
+    // This variable specifies which layer is currently being drawn by the
+	// cube interrupt routine. We assign a value to it to make sure it's not >7.
+	current_layer = 1;	
+
+	int i;
+	
+	// Boot wait
+	// This function serves 3 purposes
+	// 1) We delay starting up any interrupts, as drawing the cube causes a lot
+	//    noise that can confuse the ISP programmer.
+	// 2) Listen for button press. One button means go into rs232 mode,
+	//    The other means go into autonomous mode and start doing stuff.
+	// 3) Random seed. The bootwait function counts forever from 0 to 255.
+	//    Whenever you press the button, this counter stops, and the number it
+	//    stopped at is used as a random seed. This ensures true randomness at
+	//    every boot. Without this (or some similar process) the cube would
+	//    produce the same "random" sequence every time
+	i = bootwait();
+
+	// Enable interrupts
+	// This starts the routine that draws the cube content
+	sei();
+
+	// Result for bootwait() is 2:
+	// Go to rs232 mode. this function loops forever.
+	if (i == 2)
+	{
+		rs232();
+	}
+
+	// Result of bootwait() is something other than 2:
+	// Do awesome effects. Loop forever.
+	while (1)
+	{
+		// Show the effects in a predefined order
+		for (i=0; i<EFFECTS_TOTAL; i++)
+			launch_effect(i);
+		
+		// Show the effects in a random order.
+		// Comment the two lines above and uncomment this
+		// if you want the effects in a random order.
+		//launch_effect(rand()%EFFECTS_TOTAL);
+	}
+
+}
+
+/*
+ * Multiplexer/framebuffer routine
+ * This function is called by an interrupt generated by timer 2.
+ * Every time it runs, it does the following:
+ * 1) Disable the output for the multiplexer array.
+ * 2) Turn of all layers.
+ * 3) Load the current layer from the cube buffer onto the
+ *    multiplexer array.
+ * 4) Enable output from the multiplexer array.
+ * 5) Turn on the current layer.
+ * 6) Increment the current_layer variable, so the next layer is
+ *    drawn the next time this function runs.
+*/
+
+ISR(TIMER2_COMP_vect)
+{
+	int i;
+
+	LAYER_SELECT = 0x00; // Turn all cathode layers off. (all transistors off)
+	OE_PORT |= OE_MASK; // Set OE high, disabling all outputs on latch array
+
+	// Loop through all 8 bytes of data in the current layer
+	// and latch it onto the cube.
+	for (i = 0; i < 8; i++)
+	{
+		// Set the data on the data-bus of the latch array.
+		PORTA = cube[current_layer][i];
+		// Increment the latch address chip, 74HC138, to create
+		// a rising edge (LOW to HIGH) on the current latch.
+		LATCH_ADDR = (LATCH_ADDR & LATCH_MASK_INV) | (LATCH_MASK & (i+1));
+	}
+
+	OE_PORT &= ~OE_MASK; // Set OE low, enabling outputs on the latch array
+	LAYER_SELECT = (0x01 << current_layer); // Transistor ON for current layer
+
+	// Increment the curren_layer counter so that the next layer is
+	// drawn the next time this function runs.
+	current_layer++;
+	// We want to count from 0-7, so set it to 0 when it reaches 8.
+	if (current_layer == 8)
+		current_layer = 0;
+}
+
+
+void ioinit (void)
+{
+	DDRA = 0xff;	// DATA bus output
+	DDRB = 0xef;	// Button on B4
+	DDRC = 0xff;	// Layer select output
+	DDRD = 0xdf;	// Button on D5
+	
+	
+	PORTA = 0x00; // Set data bus off
+	PORTC = 0x00; // Set layer select off
+	PORTB = 0x10; // Enable pull up on button.
+	PORTD = 0x20; // Enable pull up on button.
+
+
+	// Timer 2
+	// Frame buffer interrupt
+	// 14745600/128/11 = 10472.72 interrupts per second
+	// 10472.72/8 = 1309 frames per second
+	OCR2 = 10; 	// interrupt at counter = 10
+    TCCR2 |= (1 << CS20) | (1 << CS22); // Prescaler = 128.
+	TCCR2 |= (1 << WGM21); // CTC mode. Reset counter when OCR2 is reached.
+	TCNT2 = 0x00;	// initial counter value = 0;
+	TIMSK |= (1 << OCIE2); // Enable CTC interrupt
+
+
+
+    // Initiate RS232
+    // USART Baud rate is defined in MYUBRR
+    UBRRH = MYUBRR >> 8;
+    UBRRL = MYUBRR;
+    // UCSRC - USART control register
+    // bit 7-6      sync/ascyn 00 = async,  01 = sync
+    // bit 5-4      parity 00 = disabled
+    // bit 3        stop bits 0 = 1 bit  1 = 2 bits
+    // bit 2-1      frame length 11 = 8
+    // bit 0        clock polarity = 0
+    UCSRC  = 0b10000110;
+    // Enable RS232, tx and rx
+    UCSRB = (1<<RXEN)|(1<<TXEN);
+    UDR = 0x00; // send an empty byte to indicate powerup.
+
+
+}
+
+// Boot wait function
+// This function does 3 things:
+// 1) Delay startup of interrupt. I've had some problems with in circuit
+//    serial programming when the cube was running. I guess switching all
+//    those LEDs on and off generates some noise.
+// 2) Set a random random seed based on the delay between boot time and
+//    the time you press a button.
+// 3) Select mode of operation, autonomous or rs232 controlled.
+unsigned int bootwait (void)
+{
+	// All the LED_PORT... code blinks the red and green status LEDs.
+
+	unsigned int x = 0;
+	LED_PORT |= LED_GREEN;
+	while (1)
+	{
+        x++; // increment x by one.
+		srand(x); // use counter x as random seed
+		
+		delay_ms(1000);
+		LED_PORT &= ~LED_GREEN; // green off, red on
+		LED_PORT |= LED_RED;
+		
+		// Listen for button presses and return with the
+		// apropriate number.
+		if (!(PIND & RS232_BTN))
+			return 2;
+
+		if (!(PINB & MAIN_BTN))
+			return 1;
+		
+		delay_ms(1000);
+		LED_PORT &= ~LED_RED; // red off, green on
+		LED_PORT |= LED_GREEN;
+		
+		// Same as above. I do it twise because there are two delays
+		// in this loop, used for the red and green led blinking..
+		if (!(PIND & RS232_BTN))
+			return 2;
+
+		if (!(PINB & MAIN_BTN))
+			return 1;
+	}
+}
+
+// Take input from a computer and load it onto the cube buffer
+void rs232(void)
+{
+	int tempval;
+	int x = 0;
+	int y = 0;
+    int escape = 0;
+	
+	while (1)
+	{
+		// Switch state on red LED for debugging
+		// Should switch state every time the code
+		// is waiting for a byte to be received.
+		LED_PORT ^= LED_RED;
+
+		// Wait until a byte has been received
+		while ( !(UCSRA & (1<<RXC)) );
+
+		// Load the received byte from rs232 into a buffer.
+		tempval = UDR;
+
+		// Uncommet this to echo data back to the computer
+		// for debugging purposes.
+		//UDR = tempval;
+
+		// Every time the cube receives a 0xff byte,
+		// it goes into sync escape mode.
+		// if a 0x00 byte is then received, the x and y counters
+		// are reset to 0. This way the x and y counters are
+		// always the same on the computer and in the cube.
+		// To send an 0xff byte, you have to send it twice!
+
+		// Go into sync escape mode
+		if (tempval == 0xff)
+		{
+			// Wait for the next byte
+			 while ( !(UCSRA & (1<<RXC)) );
+			 // Get the next byte
+			 tempval = UDR;
+
+			 // Sync signal is received.
+			 // Reset x and y counters to 0.
+			 if (tempval == 0x00)
+			 {
+				x = 0;
+				y = 0;
+                escape = 1;
+			 }
+			 // if no 0x00 byte is received, proceed with
+			 // the byte we just received.
+		}
+
+        if (escape == 0)
+        {
+		// Load data into the current position in the buffer
+		fb[x][y] = tempval;
+
+    		// Check if we have reached the limits of the buffer array.
+    		if (y == 7)
+    		{
+    			if (x == 7)
+    			{
+    				// All data is loaded. Reset both counters
+    				y = 0;
+    				x = 0;
+                    // Copy the data onto the cube.
+    				tmp2cube();
+    			} else
+    			{
+    				// A layer is loaded, reset y and increment x.
+    				x++;
+    				y = 0;
+    			}
+    		} else
+    		{
+    			// We are in the middle of loading a layer. increment y.
+    			y++;
+    		}
+	
+	    } else
+        {
+            escape = 0;
+        }
+    }
+}
+
+
-- 
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