atmega8515 without crystal

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#1
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when connecting my atmega8515 to a circuit, can i get it to work without a MHz crystall? I don't have one ;)

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Yes, the mega8515 has an internal RC oscillator. As long as you don't need precise timing, it will be fine.

Regards,
Steve A.

The Board helps those that help themselves.

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the atmega8515 has two internal speeds like most (all?) avrs, well I guess it has one, but its

8Mhz (to get this you have to burn the fusebit CKDIV8 to 1 (unprogrammed))
or
1Mhz(stock when you buy the chip, it comes like this (CKDIV8 0)

basically a 8Mhz internal clock, but there is also a internal clock divider, with CKDIV programmed, it divides the clock by 8, so 1Mhz.

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yes, most of i have used without crystals are at 1 MHz

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Quote:
the atmega8515 has two internal speeds like most (all?) avrs

Newer AVRs tend to have a system clock pre-scaler, giving them several speeds (usually 9).

Regards,
Steve A.

The Board helps those that help themselves.

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The atmega8515 is one of the older AVRs, it does not have the new clock prescaler, no CKDIV8 fuse. Instead the CKSEL fuses select one of 4 speeds:

Quote:
Table 12. Internal Calibrated RC Oscillator Operating Modes
CKSEL3..0 Nominal Frequency (MHz)
0001(1) 1.0
0010 2.0
0011 4.0
0100 8.0
Note: 1. The device is shipped with this option selected.

Regards,

Martin.