master branch is sdcard flash bootloader_from_flash is flash from an spi chip
mechanics :
The bootloader looks for byte in eeprom at address 0x63:
-if it is set to 0xF0 bootloader will look for a bin file on the sdcard named
firmware.bin and use it to flash the firmware then reset the byte to 0xFF so it
does this only once
-otherwise no action is taken and bootloader works as a arduino bootloader except
some of the debugging functions are missing
Setup ADAFruit micro sdcard 5V ready:
SDCARD on ATMEGA 2560 or ADK
pin 50 - DO
pin 51 - DI
pin 52 - CLK
pin 53 - CS
if you have an sd card shield which is different from this setup you need to change
the pinout in asmfunc.S and recompile the bootloader !!!
Flashing bootloader :
- copy the entire 'hardware' folder to your mydocuments/arduino folder
- restart arduino ide
- you should now see under tools -> boards -> Arduino mega 2560 (Dual sd bootloader) (select this)
- set the appropriate programmer
- burn bootloader
Using arduino ISP bootloader :
- connect arduino atmega 2560
- upload sketch 'Arduino ISP' (found in file -> examples)
Atmega2560 to Atmega 2560 connections:
programmer - receiver
pin 50 pin 50
pin 51 pin 51
pin 52 pin 52
pin 53 reset
5v 5v
ground ground
aditionally on programmer you have to put a capacitor between reset and ground (2.2microf works)
if you don't do this it won't work !!!
Compile bootloader:
install Crosspack (http://www.obdev.at/products/crosspack/index.html)
Navigate to My Documents/arduino/hardware/microbridge/bootladers/microbridge/
issue :
- make clean
- make all
bootloader output :
Size after:
AVR Memory Usage
----------------
Device: atmega2560
Program: 6116 bytes (2.3% Full)
(.text + .data + .bootloader)
Data: 333 bytes (4.1% Full)
(.data + .bss + .noinit)
Generate BIN file:
To generate a bin file you need issue the following command on you apps elf executable :
avr-objcopy -I elf32-avr -O binary firmware.cpp.elf firmware.bin
this generates firmware.bin which can be put on the sd for flashing your firmware. You can find the elf file in you apps build directory.
Using olimex usb to upload bootloader: avrdude -c stk500v2 -p m2560 -P /dev/tty.usbmodemfd131 -B 500 -e -u -U lock:w:0x3F:m -U efuse:w:0xFD:m -U hfuse:w:0xD8:m -U efuse:w:0xFF:m -F
avrdude -p m2560 -c stk500v2 -P /dev/tty.usbmodemfa131 -F -U flash:w:stk500boot.hex -b 115200 -B1 -U lock:w:0x0F:m
avrdude -p m168 -c usbtiny -e -u -U lock:w:0x3f:m -U efuse:w:0x00:m -U hfuse:w:0xDD:m -U lfuse:w:0xFF:m
avrdude -p m2560 -c stk500v2 -P /dev/tty.usbmodemfd131 -U flash:w:stk500boot_v2_mega2560.hex -U lock:w:0x0F:m -v
avrdude -c stk500v2 -p m2560 -P /dev/tty.usbmodemfd131 -U lock:w:0x3F:m -U efuse:w:0xFD:m -U hfuse:w:0xD8:m -U lfuse:w:0xFF:m -e -v