---
tag: m0021
title: Init SD card
brief: Attempt to detect an SD card in the slot.
author: thinkyhead

requires: SDSUPPORT
group: sdcard

codes: [ M21 ]

notes: Requires [`SDSUPPORT`](/docs/configuration/configuration.html#sd-card)

parameters:

examples:
  -
    pre: Init card with success
    code: |
      > M21
      SD card ok
      ok
  -
    pre: Init card with failure
    code: |
      > M21
      No SD card
      ok

---

Use this command to mount the last-selected SD card or thumb drive.