> Are pull up or pull down resistors needed on the MOSI, MISO & SCLK lines
> of SPI?
>
> Andrew

Since the master always drives MOSI and SCLK, no pull-ups are required
there. You MIGHT want to put a weak pull-up or pull-down on MISO if SPI
activity is infrequent to prevent a floating input on the PIC. The
floating input increases power dissipation of the PIC but is generally not
serious. I generally do not use pull-ups or pull-downs on SPI lines.
However, I'll often put a pull-up on nCS for each chip to keep multiple
devices from driving MISO before the PIC has changed the pins from their
power up input conditions to output and high.

Harold




Harold



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