Society of Robots - Robot Forum

Software => Software => Topic started by: pomprocker on April 12, 2008, 02:21:16 PM

Title: $50 robot UART - Fuse Bits & Lock Bits
Post by: pomprocker on April 12, 2008, 02:21:16 PM
how do you do the fuse part on this page

http://www.societyofrobots.com/microcontroller_uart_50_robot.shtml (http://www.societyofrobots.com/microcontroller_uart_50_robot.shtml)

With the serial Olimex AVR STK dongle programmer?

Edit: Oh yeah - I am using the Atmega8
Title: Re: $50 robot UART - fusing
Post by: pomprocker on April 12, 2008, 05:34:02 PM
To do this in PonyProg:

You would  go the menu and navigate to Command -> Security and Configuration Bits

To Change your fuse bits to 8mhz 6 ck / 14 ck +65ms

You set the CKSEL bits to 0100.

Unchecked equals unprogrammed (bit = 1)
Checked equals programmed (bit = 0)

CKSEL3 = 0
CKSEL2 = 1
CKSEL1 = 0
CKSEL0 = 0

and SUT is set to 10

SUT1 = 1
SUT0 = 0

and you have to make sure that CKOPT is unchecked (1)


I am pretty sure you can't do 8mhz on an Atmega8 without an external crystal.


EDIT: Someone told me the Internal RC oscillator on the atmega8 CAN do 8mhz
Title: Re: $50 robot UART - Fuse Bits & Lock Bits
Post by: benji on April 29, 2008, 04:03:33 PM
man,, read the datasheet

calibrated internal oscilator at 8 mhz   

CKSEL3-0 == 0100

WITH CKOPT UN-PROGRAMMED (MEANS == 1)
Title: Re: $50 robot UART - Fuse Bits & Lock Bits
Post by: pomprocker on April 29, 2008, 05:48:38 PM
Yes, I did read the datasheet. But in Admins tutorial there was a "divide by 8" bit that he unchecked. I did not see that option on the ATmega8. It must be an ATmega168 option.
Title: Re: $50 robot UART - Fuse Bits & Lock Bits
Post by: benji on April 30, 2008, 02:46:37 AM
must be somthin wrong, i did have the atmega8 data sheet and in the calibrated internal osc part it says
1 MHZ(default)
2 MHZ
4 MHZ
8 MHZ

check the fuses as i told u and ull see