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|
#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"
"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
::);
}
uint8_t _flashbuf[128];
uint8_t _inSync;
uint8_t _ok;
extern volatile uint8_t _ejected;
extern volatile uint16_t _timeout;
void Program(uint8_t ep, uint16_t page, uint8_t count)
{
uint8_t 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;
uint16_t* p = (uint16_t*)page;
uint16_t* b = (uint16_t*)_flashbuf;
for (uint8_t i = 0; i < count; i++)
boot_page_fill(p++, b[i]);
boot_page_write(page);
boot_spm_busy_wait();
boot_rww_enable ();
}
void StartSketch();
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 uint8_t _readSize[] PROGMEM;
const uint8_t _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 uint8_t _consts[] PROGMEM;
const uint8_t _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);
int main(void) __attribute__ ((naked));
// STK500v1 main loop, very similar to optiboot in protocol and implementation
int main()
{
uint8_t MCUSR_state = MCUSR; // store the reason for the reset
MCUSR &= ~(1 << WDRF); // must clear the watchdog reset flag before disabling and reenabling WDT
wdt_disable();
TX_LED_OFF();
RX_LED_OFF();
L_LED_OFF();
if (MCUSR_state & (1<<WDRF) && (pgm_read_word(0) != 0xFFFF)) {
StartSketch(); // if the reset was caused by WDT and if a sketch is already present then run the sketch instead of the bootloader
}
BOARD_INIT();
USBInit();
_inSync = STK_INSYNC;
_ok = STK_OK;
if (pgm_read_word(0) != 0xFFFF)
_ejected = 1;
for(;;)
{
uint8_t* packet = _flashbuf;
uint16_t address = 0;
for (;;)
{
uint8_t cmd = getch();
// Read packet contents
uint8_t len;
const uint8_t* rs = _readSize;
for(;;)
{
uint8_t c = pgm_read_byte(rs++);
len = pgm_read_byte(rs++);
if (c == cmd || c == 0)
break;
}
_timeout = 0;
// Read params
Recv(CDC_RX,packet,len);
// Send a response
uint8_t send = 0;
const uint8_t* pgm = _consts+7; // 0
if (STK_GET_PARAMETER == cmd)
{
uint8_t 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 = *((uint16_t*)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 uint8_t*)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
uint16_t _pulse;
void LEDPulse()
{
_pulse += 4;
uint8_t p = _pulse >> 9;
if (p > 63)
p = 127-p;
p += p;
if (((uint8_t)_pulse) > p)
L_LED_OFF();
else
L_LED_ON();
}
void StartSketch()
{
TX_LED_OFF(); // switch off the RX and TX LEDs before starting the user sketch
RX_LED_OFF();
UDCON = 1; // Detach USB
UDIEN = 0;
asm volatile ( // Reset vector to run firmware
"clr r30\n"
"clr r31\n"
"ijmp\n"
::);
}
void Reset()
{
wdt_enable(WDTO_15MS); // reset the microcontroller to reinitialize all IO and other registers
for (;;)
;
}
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