Hi, just started moving from PIC to AVR and am trying to create a low power app, so I wanted to change the clock speed to 32Khz. First thing I did was program the chip to blink an LED at 100ms intervals (using the default 1Mhz clock speed).
Then I went into AVRDude and changed the LFUSE from 0x62 (the original 1Mhz clock speed) to 0x64 (the new 32Khz clock speed) and it worked - the LED blinks a lot slower now.
problem is AVRDude will no longer connect to the chip.
the chip is an ATTiny25, and the programmer is a USBTinyISP.
AVRDude has -B and -i parameters so I figured that 1Mhz/32Khz is about 32 so I put that in as the -B parameter, the -i parameter and, in desperation, both. No love. I tried some other numbers as well, 64, 128, etc.
Can you please steer me in the right direction to connect to the chip at 32Khz?
Thanks,
DougM
Please note that I have cross-posted this to AVRFreaks, so if I get an answer there I'll cross-answer my own question here and vice versa.
newbie - changed CKSEL and now programmer won't connect
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- dougm
- Posts: 11
- Joined: Thu Feb 26, 2009 2:47 pm
- dougm
- Posts: 11
- Joined: Thu Feb 26, 2009 2:47 pm
Re: newbie - changed CKSEL and now programmer won't connect
Answering my own question here, turns out that if usbTinyISP is running at 8Mhz then the number should be 256 and...
avrdude -c usbtiny -p t25 -B 256
boom!
But if anyone has time, what is the difference between -i and -B?
Thank you,
DougM
avrdude -c usbtiny -p t25 -B 256
boom!
But if anyone has time, what is the difference between -i and -B?
Thank you,
DougM
-
- Posts: 1645
- Joined: Sat Nov 10, 2007 12:59 am
Re: newbie - changed CKSEL and now programmer won't connect
i think -B sends a delay parameter to a programmer with some local intelligence, whereas -i specifies a delay on the host for bitbang interfaces like dasa or parport.dougm wrote:But if anyone has time, what is the difference between -i and -B?
Please be positive and constructive with your questions and comments.