Forum Rule: Always post complete source code & details to reproduce any issue!
Results 1 to 5 of 5

Thread: Using 3V3 pin on T4

  1. #1
    Junior Member
    Join Date
    Oct 2019
    Posts
    10

    Using 3V3 pin on T4

    Hi!
    I am using an extern microSD card with teensy 4, can i use the 3V pin(3V3 250 mA max) as vcc for the micro SD card?

  2. #2
    Senior Member
    Join Date
    Apr 2013
    Posts
    1,924
    Yes, most SD cards run on 3.3V so that would be the expected wiring method. One thing to watch for is that writing flash memory is quite power hungry, possibly up to 100mA so if you are doing high rate writes factor that in the power budget. For just reading the values are 5-10% of that.

  3. #3
    Junior Member
    Join Date
    Oct 2019
    Posts
    10
    Hi GremlinWrangler!

    I think it will be 400 KB/m writing rate(using Class 10 Ultra SDHC) data logging, is it better to have Voltage regulator from 5V to 3V3 or the T4 can deliver 100 mA to the micro SD card?

  4. #4
    Senior Member
    Join Date
    Apr 2013
    Posts
    1,924
    Per the 250mA max note on the reference card 100mA for the SD card is not a problem unless you are also powering other things that eat into that capacity. Be aware that the standard SD card library working in SPI mode does not achieve the full throughput of a high performance card, but if your target is 400 kB a minute you should be fine.

  5. #5
    Junior Member
    Join Date
    Oct 2019
    Posts
    10
    Then it will be fine, thanks GremlinWrangler!

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •