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#include "Platform.h"
// This bootloader creates a composite Serial/Mass storage device
//
// The serial interface supports a STK500v1 protocol that is very similar to optiboot
// The mass storage interface emulates a disk image that is used to read or write firmware.bin files
// Delete firmware.bin and copy a new binary (not .hex) file to flash the firmware i.e:
//
// cp firmware.bin f:/. -f
//
// Ejecting the disk will run the firmware
//
// 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"
"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;
extern volatile u8 _ejected;
extern volatile u16 _timeout;
void Program(u8 ep, u16 page, u8 count)
{
u8 write = page < 30*1024; // Don't write over firmware please
if (write)
boot_page_erase(page);
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 ();
}
int USBGetChar();
#define getch USBGetChar
#define HW_VER 0x02
#define SW_MAJOR 0x01
#define SW_MINOR 0x10
#define STK_OK 0x10
#define STK_INSYNC 0x14 // ' '
#define CRC_EOP 0x20 // 'SPACE'
#define STK_GET_SYNC 0x30 // '0'
#define STK_GET_PARAMETER 0x41 // 'A'
#define STK_SET_DEVICE 0x42 // 'B'
#define STK_SET_DEVICE_EXT 0x45 // 'E'
#define STK_LOAD_ADDRESS 0x55 // 'U'
#define STK_UNIVERSAL 0x56 // 'V'
#define STK_PROG_PAGE 0x64 // 'd'
#define STK_READ_PAGE 0x74 // 't'
#define STK_READ_SIGN 0x75 // 'u'
extern const u8 _readSize[] PROGMEM;
const u8 _readSize[] =
{
STK_GET_PARAMETER, 1,
STK_SET_DEVICE, 20,
STK_SET_DEVICE_EXT, 5,
STK_UNIVERSAL, 4,
STK_LOAD_ADDRESS, 2,
STK_PROG_PAGE, 3,
STK_READ_PAGE, 3,
0,0
};
extern const u8 _consts[] PROGMEM;
const u8 _consts[] =
{
SIGNATURE_0,
SIGNATURE_1,
SIGNATURE_2,
HW_VER, // Hardware version
SW_MAJOR, // Software major version
SW_MINOR, // Software minor version
0x03, // Unknown but seems to be required by avr studio 3.56
0x00, //
};
void USBInit(void);
extern u8 _sector3[512];
int main(void) __attribute__ ((naked));
// STK500v1 main loop, very similar to optiboot in protocol and implementation
int main()
{
BOARD_INIT();
USBInit();
#ifdef WRITABLE_DIRECTORY
_sector3[0] = 0;
#endif
_inSync = STK_INSYNC;
_ok = STK_OK;
#ifndef MSC_ENABLED
if (pgm_read_word(0) != -1)
_ejected = 1;
#endif
for(;;)
{
u8* packet = _flashbuf;
u16 address = 0;
for (;;)
{
u8 cmd = getch();
// 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;
}
#ifndef MSC_ENABLED
_timeout = 0;
#endif
// 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)
{
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;
}
_ejected = 1;
}
}
// Nice breathing LED indicates we are in the firmware
u16 _pulse;
void LEDPulse()
{
_pulse++;
u8 p = _pulse >> 8;
if (p > 127)
p = 255-p;
p += p;
if (((u8)_pulse) > p)
LED0;
else
LED1;
}
void Reboot()
{
UDCON = 1; // Detatch USB
UDIEN = 0;
asm volatile ( // Reset vector to run firmware
"clr r30\n"
"clr r31\n"
"ijmp\n"
::);
}
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