AnsweredAssumed Answered

SPI interface question in the LPC55S69-EVK

Question asked by StanleyH Employee on Nov 20, 2019
Latest reply on Nov 25, 2019 by Eugene Hiihtaja

Hi support team,


  There are three 2.2Kohm pull-up resistors connected on the LPC55S69 SPI interface in our LPC55S69 EVB. 


Would like to ask why it needs these pull-up R for a SPI bus which has no pull-up R in general.

Are these R necessary ? Are our SPI pins(SPI_MISO, SPI_MOSI, SPI_SSEL) open-drain and must pull high externally ?  or transmission speed concern.




Customer: Ecolux