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Topic: Bootloader problem when SPI slave connected (Read 1 time) previous topic - next topic

MarkT

Floating CMOS inputs aren't compatible with very low power!  Just make sure the 'normal' state is the one you pull to (so CS bar should be pulled up, SCLK pulled down, etc).  Use 47k resistors rather than 1k...   Still I'm not sure if this causes the original problem, but it might be sending the RF chip haywire if the inputs gates are oscillating or shooting-through.  Sure the 3V3 supply is providing enough current during upload (the FTDI chip only provides 50mA I think, if its an FTDI cable).
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estratos

You're making very good observations.

There are no floating pins except during the bootloading I think. I'll check the in-line and pull-up/down resistor stuff. I too think that a high impedance output on the SPI bus could be causing the problem. As for the maximum power provided by the FTDI chip I'll check it too. The CC1101 sinks much less than 50 mA but again I don't know about the consumption of the atmega during the upload process.

Thanks again!

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