Skip to main content
G
G.Lumeau
Visitor II
August 28, 2019
Question

LIS3DH - Current drive by SO pin

  • August 28, 2019
  • 1 reply
  • 549 views

Hi,

My LIS3DH share SPi bus with an other component which has an internal pull-up (arround 15kOhm).

When I start a communication with my LIS3DH, SO pin never be at 0V.

I see drop voltage arround 0.5V, on SO pin. SI and CLK pin's level are ok.

I have disable internal SO pullup on LIS3DH but how many current could be drive by SO pin ?

When a try to set voltage at 0V I drive arround 300µA.

Thks for your help

    This topic has been closed for replies.

    1 reply

    E
    Eleon BORLINI
    ST Employee
    September 18, 2019

    Hi @Grégoire Lumeau​ , the current consumption will be decreased also if you connect the SDO/SA0 pin to Vcc. Inside the LIS3DH is pull-up resistor, so if you connect the pin to ground the current is flowing from Vcc through the pull-up resistor to ground, on the contrary if you connect the pin to Vcc there won't be any current as the voltage is the same on both side of the pull up. For the Vcc=2.5V the typical value of internal pull-up on SDA/SA0 pin is 30.4kohm. So the current should be 80uA. Did you already disable the internal pull-ups in CTRL_REG0 register?

    Please ref also to this topic if can be of your help. Regards

    Terms & ConditionsAccessibility statement