ISP of 8535 with Pullups on the SPI Port

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Does anyone know if there will be issues programming an 8535 over the SPI port with external pullups?

I'm not sure how the ISP programming will be effected because the RESET is asserted while ISP programming which sets PORTB and DDRB to 0x00 wich puts the pins in a tristate mode. If I have pullups external to my part then the programmer isn't really seeing a tristate pin.

Erick

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There will not be issues programming an 8535 over the SPI port with external pullups unless the pullups are too low in value. When the processor is reset the pins indeed become tri-stated, and MOSI and SCK can be driven. Once the first two bytes of the Programming Enable instruction are recognized, the MISO pin becomes an output. As long as your source and the 8535 can drive the signals with the pullups present, you will be ok.
Dave Raymond

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