I had used the Mega256 SCh to build my board, Using Arduino mega as ISP to burn sketch, I had loaded boot loader from Arduino IDE. and when I downloaded the blink led code. Led responding slow. same with Serial code. delay of 100 acting as of 1000 on my board in code baud rate in 9600 but i am getting proper value when i set 4800 in serial monitor. Can any one point out the problem Thanks
If your ans regarding to fuse than please specify which one and also which fuse has to set to use external osc.
Look at boards.txt for the Mega2560 board, the fuse settings you need are there.
Can verify them with Nick Gammon's tool here:
I had match fuse setting nothing changed.
Also can you specify the fuse which decide weather to use internal or external oscillator.
Also i am unable to program the mega via usb but getting response when using the serial monitor
DFU file was selected properly.
My boards.txt
mega.upload.tool=avrdude
mega.upload.maximum_data_size=8192
mega.bootloader.tool=avrdude
mega.bootloader.low_fuses=0xFF
mega.bootloader.unlock_bits=0x3F
mega.bootloader.lock_bits=0x0F
mega.build.f_cpu=16000000L
mega.build.core=arduino
mega.build.variant=mega
default board may be overridden by the cpu menu
mega.build.board=AVR_MEGA2560
Table 30-5. Low Fuse Byte:
Bit No Description Default Value
CKDIV8(4) 7 Divide clock by 8 0 (programmed)
CKOUT(3) 6 Clock output 1 (unprogrammed)
SUT1 5 Select start-up time 1 (unprogrammed)(1)
SUT0 4 Select start-up time 0 (programmed)(1)
CKSEL3 3 Select Clock source 0 (programmed)(2)
CKSEL2 2 Select Clock source 0 (programmed)(2)
CKSEL1 1 Select Clock source 1 (unprogrammed)(2)
CKSEL0 0 Select Clock source 0 (programmed)(2)
2. The default setting of CKSEL3:0 results in internal RC Oscillator @ 8MHz. See Table 10-1 on page 40 for details.
Table 10-1
Device Clocking Options Select(1)
Device Clocking Option CKSEL3:0
Low Power Crystal Oscillator 1111 - 1000
Full Swing Crystal Oscillator 0111 - 0110
Low Frequency Crystal Oscillator 0101 - 0100
Internal 128kHz RC Oscillator 0011
Calibrated Internal RC Oscillator 0010
External Clock 0000
Reserved 0001
Note: 1. For all fuses “1” means unprogrammed while “0” means programmed.