AVR-ISP

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#1
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Hi everyone ,

I hv a question about AVR-ISP. I hv an RF module(CC1101) and the MCU i'm using to program it is ATmega168A n AVR_ISP loader.When the AVR_ISP is pluged in everything works fine but when removed the mcu doesn't run the program.The RF and the Atmega talk with SPI and the AVR_ISP also uses SPI.S o i thought of inserting a pull up resister for slave select pin(SS) but it doesn't help.When there is the ISP pluged in ev"thing works fine.Can anyone give me a suggestion ASAP  plsss ?

                                                                                                         Best Regards,

                                                                                                                          Mekdelawit

GonnaBawesome

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Usually when things work with a programmer attached and not without it, it is because the programmer was providing a common ground.

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I checked if the programmer provides the common ground and it sure doesn't.they all get it from the voltage regulator.Any other reason  ?

 

GonnaBawesome

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Got a pullup on the AVR's reset line?  10k is good.

 

S.

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yeah , there is a pull up on the reset pin 4.7K.
 

GonnaBawesome

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10k would be a better choice for Reset pullup. It would make the mega168 compatible with debugWIRE.
Likewise, you want an external pullup on every SPI chip select to ensure they are in 3-state during ISP programming.
.
Post a schematic. A pencil sketch is fine. Just as long as it is readable.

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 I used 10K resistor and it works perfectly.Thank you everyone....................

GonnaBawesome