Yes, the avrdude command/parameters.
This part here changes the CKSEL bits? lfuse:w:0xe0:m
Why does the upper bit of 0xff get changed as well?
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)
Note: 1. The default value of SUT1...0 results in maximum start-up time for the default clock source.
See Table 9-12 on page 34 for details.
2. The default setting of CKSEL3...0 results in internal RC Oscillator @ 8MHz. See Table 9-11 on
page 34 for details.
3. The CKOUT Fuse allows the system clock to be output on PORTB0. See ”Clock Output Buffer”
on page 36 for details.
4. See ”System Clock Prescaler” on page 36 for details.
So have bit 7 = 0 means Divide by 8 is enabled? I still want to run at 16 MHz.
The clock will be coming from Xtal2 on the 2nd 328 in the dual-328 system I am proofing out, and go into Xtal1.
PB0 will not be changed, and PB7 should be free'd up as well. I suppose that could be added to pins_arduinio.h as well to have another IO pin.