HW spirit

[maengtae]

Posted on March 13, 2014 at 16:19

what is the electrical configuration of the SPI pins of SPIRIT1 (MISO,MOSI,SCLK,CSn). For outputs I guess it is push/pull, for inputs is it floating, with pull-up? Please can you advise ? Similar question for GPIOs.

[Nickname1920_O]

Posted on March 14, 2014 at 08:09

Hello,

as regards the SPI, the output pin (MISO) is configurated as push/pull so no resistor has to be placed. Regarding the input pins, they are configurated as floating. In this case you have to put a pull-up resistor for the pin CSn because it is active low; for the MOSI and CLK you can put a pull-up or a pull-down indifferently.  Instead the GPIO can be set in different modes. When they are set as digital, the functionality is exactly the same of the SPI: if they are set as output no pull resistor is necessary, when they are set as input they are floating so a pull-up or down resistor is necessary. For this scope a resistor value of 100KOhm is the most suitable one.Best regards,Gaetano