restored original non-interrupt-driven DiskLoader

Interrupt-driven version was a dead-end - too many bugs with that approach.

1 files changed, 145 insertions, 159 deletions

diff --git a/bootloaders/diskloader/src/DiskLoader.cpp b/bootloaders/diskloader/src/DiskLoader.cpp
index 2792bc6..6580618 100644
--- a/bootloaders/diskloader/src/DiskLoader.cpp
+++ b/bootloaders/diskloader/src/DiskLoader.cpp
@@ -1,67 +1,64 @@
-/*
- *  DiskLoader.cpp
- */
+
 
 #include "Platform.h"
 
+//	This bootloader creates a composite Serial device
+//
+//	The serial interface supports a STK500v1 protocol that is very similar to optiboot
+//
+//	The bootloader will timeout and start the firmware after a few hundred milliseconds
+//	if a usb connection is not detected.
+//	
+//	The tweakier code is to keep the bootloader below 2k (no interrupt table, for example)
+
 extern "C"
 void entrypoint(void) __attribute__ ((naked)) __attribute__ ((section (".vectors")));
 void entrypoint(void)
 {
 	asm volatile (
-				  "eor	r1,		r1\n"	// Zero register
-				  "out	0x3F,	r1\n"	// SREG
-				  "ldi	r28,	0xFF\n" // Y-register
-				  "ldi	r29,	0x0A\n"	// Y-register
-				  "out	0x3E,	r29\n"	// SPH
-				  "out	0x3D,	r28\n"	// SPL
-				  "rjmp	main"			// Stack is all set up, start the main code
-				  ::);
+		"eor	r1,		r1\n"	// Zero register
+		"out	0x3F,	r1\n"	// SREG
+		"ldi	r28,	0xFF\n"
+		"ldi	r29,	0x0A\n"
+		"out	0x3E,	r29\n"	// SPH
+		"out	0x3D,	r28\n"	// SPL
+		"rjmp	main"			// Stack is all set up, start the main code
+		::);
 }
 
 u8 _flashbuf[128];
 u8 _inSync;
 u8 _ok;
-u16 do_reset = 0;
-volatile u16 _timeout = 0;
+extern volatile u8 _ejected;
+extern volatile u16 _timeout;
 
 void Program(u8 ep, u16 page, u8 count)
 {
-	u8 write = page < 28*1024;		// Don't write over bootloader please
+	u8 write = page < 30*1024;		// Don't write over firmware please
 	if (write)
 		boot_page_erase(page);
-	
-	USB_Recv_block(ep,_flashbuf,count);	// Read while page is erasing
-	
+
+	Recv(ep,_flashbuf,count);		// Read while page is erasing
+
 	if (!write)
 		return;
-	
+
 	boot_spm_busy_wait();			// Wait until the memory is erased.
-	
+
 	count >>= 1;
 	u16* p = (u16*)page;
 	u16* b = (u16*)_flashbuf;
 	for (u8 i = 0; i < count; i++)
 		boot_page_fill(p++, b[i]);
-	
+
     boot_page_write(page);
     boot_spm_busy_wait();
     boot_rww_enable ();
 }
 
-u16 _pulse;
-void LEDPulse() 
-{
-	_pulse += 1;
-	u8 p = _pulse >> 9;
-	if (p > 63)
-		p = 127-p;
-	p += p;
-	if (((u8)_pulse) > p)
-		L_LED_OFF();
-	else
-		L_LED_ON();
-}
+
+int USBGetChar();
+#define getch USBGetChar
 
 #define HW_VER	 0x02
 #define SW_MAJOR 0x01
@@ -107,147 +104,136 @@ const u8 _consts[] =
 	0x00,		// 
 };
 
-void start_sketch()
-{
-	if (pgm_read_word(0) == -1)		// no sketch has been uploaded yet - stay in bootloader
-		return;
-	
-	L_LED_OFF();
-	RX_LED_OFF();
-	TX_LED_OFF();
-	/* move interrupts to application section:
-	 * uses inline assembly because the procedure must be completed in four cycles.
-	 */
-	cli();	// disable interrupts first
-	asm volatile (
-				  "ldi r16,	  0x01\n"		// (1<<IVCE)	/* Enable change of interrupt vectors */
-				  "out 0x35,  r16\n"		// MCUCR
-				  "ldi r16,	  0x00\n"		// (1<<IVSEL)	/* Move interrupts to application flash section */
-				  "out 0x35,  r16\n"		// MCUCR				  
-				  );							
-	UDCON = 1;		// Detatch USB
-	UDIEN = 0;
-	asm volatile (	// Reset vector to run firmware
-				  "clr r30\n"
-				  "clr r31\n"
-				  "ijmp\n"
-				  ::);
-}
 
+void USBInit(void);
 int main(void) __attribute__ ((naked));
-int main() 
-{		
+
+//	STK500v1 main loop, very similar to optiboot in protocol and implementation
+int main()
+{
 	wdt_disable();
+	TXLED0;
+	RXLED0;
+	LED0;
 	BOARD_INIT();
-	/* move interrupts to boot section:
-	 * uses inline assembly because the procedure must be completed in four cycles.
-	 * seems to fail if called before disabling WDT and calling BOARD_INIT()
-	 */
-	asm volatile (
-				  "ldi r16,	  0x01\n"		// (1<<IVCE)	/* Enable change of interrupt vectors */
-				  "out 0x35,  r16\n"		// MCUCR
-				  "ldi r16,	  0x02\n"		// (1<<IVSEL)	/* Move interrupts to boot flash section */
-				  "out 0x35,  r16\n"		// MCUCR				  
-				  );	
-	TX_LED_OFF();
-	RX_LED_OFF();
-	L_LED_OFF();
-	USB.attach();	
-	sei();
-	
+	USBInit();
+
 	_inSync = STK_INSYNC;
 	_ok = STK_OK;
-	
-	for (;;) 
+
+	if (pgm_read_word(0) != -1)
+		_ejected = 1;
+
+	for(;;)
 	{
 		u8* packet = _flashbuf;
 		u16 address = 0;
 		for (;;)
-		{		
-			if (USB_Available(CDC_RX)) 
+		{
+			u8 cmd = getch();
+
+			//	Read packet contents
+			u8 len;
+			const u8* rs = _readSize;
+			for(;;)
 			{
-				u8 cmd = USB_Recv(CDC_RX);
-				
-				// Read packet contents
-				u8 len;
-				const u8* rs = _readSize;
-				for (;;) 
-				{
-					u8 c = pgm_read_byte(rs++);
-					len = pgm_read_byte(rs++);
-					if (c == cmd || c == 0)
-						break;
-				}
-				_timeout = 0;
-				// Read params
-				USB_Recv_block(CDC_RX, packet, len);
-				
-				// Send a response
-				u8 send = 0;
-				const u8* pgm = _consts+7;
-				if (STK_GET_PARAMETER == cmd)
-				{
-					u8 i = packet[0] - 0x80;
-					if (i > 2)
-						i = (i==0x18) ? 3 : 4;	
-					pgm = _consts + i + 3;
-					send = 1;
-				} 
-				else if (STK_UNIVERSAL == cmd) 
-				{
-					if (packet[0] == 0x30)
-						pgm = _consts + packet[2];	
-					send = 1;
-				}
-				else if (STK_READ_SIGN == cmd)
-				{ 
-					pgm = _consts;
-					send = 3;
-				}
-				else if (STK_LOAD_ADDRESS == cmd) 
-				{
-					address = *((u16*)packet);	// word address
-					address += address;
-				}
-				else if (STK_PROG_PAGE == cmd)
-				{
-					Program(CDC_RX, address, packet[1]);
-				}
-				else if (STK_READ_PAGE == cmd)
-				{
-					send = packet[1];
-					pgm = (const u8*)address;
-					address += send;
-				}
-				
-				u16 countdown = 5000;
-				while (countdown-- > 10 && !USB_Available(CDC_RX)) 
-					;
-				int x = USB_Recv(CDC_RX);
-				if (x != -1 && x != ' ')
+				u8 c = pgm_read_byte(rs++);
+				len = pgm_read_byte(rs++);
+				if (c == cmd || c == 0)
 					break;
-				
-				USB_Send(CDC_TX, &_inSync, 1);
-				
-				if (send) 
-					USB_Send(CDC_TX|TRANSFER_PGM, pgm, send);
-				
-				// Send ok
-				USB_Send(CDC_TX|TRANSFER_RELEASE, &_ok, 1);
-				
-				if ('Q' == cmd) 
-				{
-					_delay_ms(100);
-					start_sketch();
-				}
 			}
-			else 
+			_timeout = 0;
+			//	Read params
+			Recv(CDC_RX,packet,len);
+
+			//	Send a response
+			u8 send = 0;
+			const u8* pgm = _consts+7;			// 0
+			if (STK_GET_PARAMETER == cmd)
+			{
+				u8 i = packet[0] - 0x80;
+				if (i > 2)
+					i = (i == 0x18) ? 3 : 4;	// 0x80:HW_VER,0x81:SW_MAJOR,0x82:SW_MINOR,0x18:3 or 0
+				pgm = _consts + i + 3;
+				send = 1;
+			}
+
+			else if (STK_UNIVERSAL == cmd)
 			{
-				LEDPulse();
-				_delay_us(100);
-				if (_timeout-- == 1)
-					start_sketch();
+				if (packet[0] == 0x30)
+					pgm = _consts + packet[2];	// read signature
+				send = 1;
 			}
+			
+			//	Read signature bytes
+			else if (STK_READ_SIGN == cmd)
+			{
+				pgm = _consts;
+				send = 3;
+			}
+
+			else if (STK_LOAD_ADDRESS == cmd)
+			{
+				address = *((u16*)packet);		// word addresses
+				address += address;
+			}
+
+			else if (STK_PROG_PAGE == cmd)
+			{
+				Program(CDC_RX,address,packet[1]);
+			}
+
+			else if (STK_READ_PAGE == cmd)
+			{
+				send = packet[1];
+				pgm = (const u8*)address;
+				address += send; // not sure of this is required
+			}
+
+			// Check sync
+			if (getch() != ' ')
+				break;
+			Transfer(CDC_TX,&_inSync,1);
+
+			// Send result
+			if (send)
+				Transfer(CDC_TX|TRANSFER_PGM,pgm,send);	// All from pgm memory
+
+			//	Send ok
+			Transfer(CDC_TX|TRANSFER_RELEASE,&_ok,1);
+
+			if (cmd == 'Q')
+				break;
 		}
+		_timeout = 500;		// wait a moment before exiting the bootloader - may need to finish responding to 'Q' for example
+		_ejected = 1;
 	}
 }
+
+//	Nice breathing LED indicates we are in the firmware
+u16 _pulse;
+void LEDPulse()
+{
+	_pulse += 4;
+	u8 p = _pulse >> 9;
+	if (p > 63)
+		p = 127-p;
+	p += p;
+	if (((u8)_pulse) > p)
+		LED0;
+	else
+		LED1;
+}
+
+void Reboot()
+{
+	TXLED0;		// switch off the RX and TX LEDs before starting the user sketch
+	RXLED0;
+	UDCON = 1;		// Detatch USB
+	UDIEN = 0;
+	asm volatile (	// Reset vector to run firmware
+		"clr r30\n"
+		"clr r31\n"
+		"ijmp\n"
+	::);
+}