From a2859762b7c7dfd0f9aeffec6f87e7866e6fe1b5 Mon Sep 17 00:00:00 2001
From: Jon Langseth <jon.langseth@lilug.no>
Date: Thu, 27 Jun 2013 18:23:17 +0200
Subject: [PATCH] Updated to reflect Hardware Rev 1

---
 Makefile |  6 ++---
 fbosd.c  | 72 +++++++++++++++++++++++++++++++++++++++-----------------
 2 files changed, 54 insertions(+), 24 deletions(-)
 mode change 100755 => 100644 Makefile

diff --git a/Makefile b/Makefile
old mode 100755
new mode 100644
index ad0e941..783fdcd
--- a/Makefile
+++ b/Makefile
@@ -8,6 +8,9 @@
 # This modified template is placed in the public domain like the original.
 #
 
+#AVRDUDE_PROGRAMMER = usbasp
+AVRDUDE_PROGRAMMER = usbtiny
+AVRDUDE_PORT = usb
 
 # Target name and MCU setup -------------------------------------------------
 
@@ -159,9 +162,6 @@ LDFLAGS = $(EXTMEMOPTS) $(LDMAP) $(PRINTF_LIB) $(SCANF_LIB) $(MATH_LIB)
 
 # Programming support using avrdude. Settings and variables.
 
-AVRDUDE_PROGRAMMER = usbtiny
-AVRDUDE_PORT = usb
-
 AVRDUDE_WRITE_FLASH = -U flash:w:$(TARGET).hex
 #AVRDUDE_WRITE_EEPROM = -U eeprom:w:$(TARGET).eep
 
diff --git a/fbosd.c b/fbosd.c
index aa1127a..c30ee9b 100644
--- a/fbosd.c
+++ b/fbosd.c
@@ -22,13 +22,34 @@ void Delay_ms(int cnt)
 	while(cnt-->0) _delay_ms(1);
 }
 
+void set_busy ( uint8_t busy)
+{
+	if ( busy )
+	{
+		// Set busy signal
+		PORTB |= (1 << PB1);
+		
+		// TODO: Disable SPI communication here...
+	}
+	else
+	{
+		// Clear Busy signal
+		PORTB &= ~(uint8_t)(1 << PB1);
+
+		// TODO: Enable SPI communication here...
+	}
+}
+
 void active_lines ( void )
 {
 	static uint8_t rept;
 
 	_delay_us(4);
 
+	// Set Busy signal. Line rendering is time-critical.
+	set_busy(1);
 	asm_render_line();
+	set_busy(0);
 
 	if( !rept )
 	{
@@ -42,11 +63,14 @@ void active_lines ( void )
 
 void blank_lines ( void )
 {
+	// Do nothing on the "lead-in" lines
 	if ( line < FIRST_LINE )
-	{
-		PORTB ^= 0x004;
 		return;
-	}
+
+	// Clear Frame Ready signal
+	PORTD &= ~(uint8_t)(1 << PD5);
+
+	// Activate rendering
 	line_handler = active_lines;
 }
 
@@ -60,6 +84,10 @@ ISR (INT1_vect)
 		buffer_position = 0;
 		line_handler = &blank_lines;
 		EIMSK &= ~(uint8_t)(1<<INT1);
+		
+		// Set Frame Ready signal
+		PORTD |= (1 << PD5);
+		
 	}
 }
 
@@ -78,17 +106,25 @@ ISR (INT0_vect)
 //Main Function
 int main(void)
 {
-	
 	// Note: PB0 is used as CLKO outputting 20MHz clock to ATtiny
-
-	// Using some pins on PORTB for debug-indicator-LEDs
-	DDRB = (1 << PB1)|(1 << PB2);
-	PORTB = 0x0;
-
+	
+	// Set PB2 as Output for BUSY signal
+	DDRB = (1 << PB1);
+	
+	// Set PD5 as Output for FR signal
+	// Set PD6 as Output for Status LED
 	// Using pin 7 on PD to clock out pixels \o/
-	DDRD = (1<<PD7);
+	DDRD = (1<<PD5)|(1<<PD6)|(1<<PD7);
+	
+	// Clear PORTB and PORTD
+	PORTB = 0x0;
 	PORTD = 0x0;
 
+	// Allocate the framebuffer :D
+	screen_buffer = (uint8_t*) malloc( hres_bytes * VRES * sizeof(uint8_t) );
+	// And make sure it's cleared
+	fill(c_BLACK);
+
 	/* LM1881 pins are connected to:
 	INT0 / PCINT18 / PD2 <- VSYNC
 	INT1 / PCINT19 / PD3 <- CSYNC
@@ -96,16 +132,11 @@ int main(void)
 	*/
 	EICRA |= (1<<ISC01)|(1<<ISC00); // Select Rising-edge interrupt for VSync
 	EICRA |= (1<<ISC11)|(1<<ISC10); // Select Rising-edge interrupt for HSync
-	EIMSK |= (1<<INT0); // Enable VSync-interrupts
+	EIMSK |= (1<<INT0); 			// Enable VSync-interrupts
 
-	// And enable interrupts globally.
+	// Enable interrupts globally.
 	sei();
 
-	// Allocate the framebuffer :D
-	screen_buffer = (uint8_t*) malloc( hres_bytes * VRES * sizeof(uint8_t) );
-	// And make sure it's cleared
-	fill(c_BLACK);
-
 	// Do some static drawing :P
 	set_pixel(28, 8, 1);
 	set_pixel(92, 82, 1);
@@ -113,7 +144,6 @@ int main(void)
 	set_pixel(92, 8, 1);
 	set_pixel(28, 82, 1);
 
-
 	draw_line(0, 0, 128, 92, 1);
 	draw_line(128, 0, 0, 92, 1);
 
@@ -131,11 +161,11 @@ int main(void)
 	fill_rect( 38, 25, 52, 42, 1);
 	fill_rect( 41, 28, 46, 36, 0);
 
-	//fill_rect( 54, 41, 20, 10, 0);
-
 	for (;;)
 	{
-	 	PORTB ^= 0x002;
+		// Toggle status LED
+		PORTD ^= (uint8_t)(1 << PD6);
+		
 		for ( int j = 0; j < 92; j++ )
 		{
 			draw_line(0,0,128,j, 2);
-- 
2.39.2