o add gnususb as reference bootloader

o refactor boot loader  cpde
o

tools/gnusb/bootloader/firmware/snesram_bootloader.c

@@ -0,0 +1,164 @@
+/*
+ * =====================================================================================
+ *
+ *       Filename:  snesram_bootloader.c 
+ *
+ *    Description:
+ *
+ *        Version:  1.0
+ *        Created:  05/06/2009 03:06:26 PM
+ *       Revision:  none
+ *       Compiler:  gcc
+ *
+ *         Author:  David Voswinkel (DV), david@optixx.org
+ *        Company:  Optixx
+
+ *      inspired by
+ *      AVRUSBBoot - USB bootloader for Atmel AVR controllers
+ *      Thomas Fischl <tfischl@gmx.de>
+ *
+ * =====================================================================================
+ */
+
+#include <avr/io.h>
+#include <avr/interrupt.h>
+#include <avr/pgmspace.h>
+#include <avr/wdt.h>
+#include <avr/boot.h>
+
+#include "usbdrv.h"
+#include "../usb_cmds.h"        
+
+#define SNESRAM_BOOT_SOFTJUMPER_ADDRESS	0x05
+#define SNESRAM_BOOT_SOFTJUMPER			0xd9
+
+
+static uchar replyBuffer[8];    // reply buffer for USB
+static unsigned int page;       // address of page we're currently writing to
+static unsigned int byte_counter;       // address of next byte to write to
+static uchar ready;
+
+void (*jump_to_app) (void) = 0x0000;
+
+void leaveBootloader()
+{
+    cli();
+    boot_rww_enable();
+    GICR = (1 << IVCE);         /* enable change of interrupt vectors */
+    GICR = (0 << IVSEL);        /* move interrupts to application flash section */
+    jump_to_app();
+}
+
+void writePage(void)
+{
+    PORTD ^= (1 << 5);          // Toggle yellow led
+
+    eeprom_busy_wait();
+
+    cli();
+    boot_page_erase(page);      // erase page
+    boot_spm_busy_wait();       // wait until page is erased
+    boot_page_write(page);      // Store buffer in flash page.
+    boot_spm_busy_wait();       // Wait until the memory is written.
+    sei();
+
+    byte_counter = 0;
+    page += SPM_PAGESIZE;
+}
+
+uchar usbFunctionSetup(uchar data[8])
+{
+    uchar len = 0;
+
+    usbMsgPtr = replyBuffer;
+
+    if (data[1] == SNESRAM_BOOT_CMD_LEAVE) {
+        usbDeviceDisconnect();
+        leaveBootloader();
+
+    } else if (data[1] == SNESRAM_BOOT_CMD_START) {
+        page = 0;
+        byte_counter = 0;
+        ready = 1;
+    } else if (data[1] == SNESRAM_BOOT_CMD_STATUS) {
+
+        if (byte_counter >= SPM_PAGESIZE) {
+            writePage();
+        }
+        replyBuffer[0] = ready;
+        len = 1;
+
+    } else if (data[1] == SNESRAM_BOOT_CMD_WRITE) {
+
+        replyBuffer[0] = data[2];
+        replyBuffer[1] = data[3];
+        len = 2;
+
+        cli();
+        boot_page_fill(page + byte_counter, data[3] | (data[2] << 8));
+        sei();
+
+        byte_counter += 2;
+
+    } else if (data[1] == SNESRAM_BOOT_CMD_FINISH) {
+        if (byte_counter) {
+            writePage();
+        }
+        ready = 0;
+        PORTD &= ~(1 << 5);     // Light yellow Led 
+
+    } else if (data[1] == SNESRAM_BOOT_CMD_CLEAR_FLAG) {
+
+        while (EECR & (1 << EEWE)) ;
+        // write 00 to eeprom
+        EEARL = SNESRAM_BOOT_SOFTJUMPER_ADDRESS;
+        EEDR = 0x00;
+        cli();
+        EECR |= 1 << EEMWE;
+        EECR |= 1 << EEWE;      // must follow within a couple of cycles -- therefore cli() 
+        sei();
+
+    }
+
+    return len;
+}
+
+int main(void)
+{
+    // set PORT D Directions -> 1110 0000, output 0 on USB pullup PD7
+    DDRD = 0xe0;                // 1110 0000 -> set PD0..PD4 to inputs -> USB pins
+    PORTD = 0x70;               // 0111 0000 -> set Pullup for Bootloader Jumper, no pullups on USB pins
+
+    // see if hardware jumper is set
+    if (!((PIND & (1 << 4)) == 0)) {
+
+        // no jumper, let's see if we have softjumper flag in EEPROM            
+        while (EECR & (1 << EEWE)) ;
+        EEARL = SNESRAM_BOOT_SOFTJUMPER_ADDRESS;
+        EECR |= 1 << EERE;
+        if (EEDR != SNESRAM_BOOT_SOFTJUMPER)
+            leaveBootloader();
+    }
+
+    GICR = (1 << IVCE);         // enable change of interrupt vectors 
+    GICR = (1 << IVSEL);        // move interrupts to boot flash section 
+
+    uchar i, j;
+    PORTD = 0xd0;               // 1101 0000 -> pull up pd7 for device connect, pullup on jumper, light yellow led to show we're in bootloader
+    DDRD = 0xe3;                // 1110 0011 -> set USB pins to output -> SE0
+    j = 0;
+    while (--j) {
+        i = 0;
+        while (--i) ;           // delay >10ms for USB reset
+    }
+
+    DDRD = 0xe0;                // 1110 0000 -> set USB pins to input
+
+    usbInit();
+    sei();                      // turn on interrupts
+
+    while (1) {                 // main event loop
+        usbPoll();
+    }
+    return 0;
+}