Shop OBEX P1 Docs P2 Docs Learn Events
microSD size — Parallax Forums

microSD size

bitnerdbitnerd Posts: 10
in Propeller 1

Does anyone know what the maximum size is for a Propellor 1 project board microSD?

Comments

  • Wuerfel_21Wuerfel_21 Posts: 5,684

    depends on the driver object you use to access it. There are a few older ones floating around that only work with <= 2GB cards (plain SD). The more usual ones should work with <= 32GB (SDHC). You can then make <= 2TB (SDXC) work by reformatting them to FAT32 (SDHC->SDXC transition didn't change the hardware protocol, just the factory formatting from FAT32 to exFAT)

  • evanhevanh Posts: 16,835
    edited 2025-10-28 22:06

    I haven't seen any SDSC only drivers, but their protocol (Byte addressing) prevents them from working with > 2GB cards (Block addressing).

    SDUC for over 2TB, up to 128TB, isn't supported. It adds prefixing complexity, like an ACMD, to the block addressing and I suspect will require more error handling.

    EDIT: That said, it looks like a SDUC card will act as a 2 TB SDHC by default. The extension feature looks to be only activated if the driver requests it in the early ACMD41. The trick then is to format the card with first FAT32 partition contained entirely in the first 2 TB of the card.

    EDIT2: Oh, and that would go for a SDSC driver too. A SDHC card will act as a 2GB SDSC card if the driver doesn't request for SDHC (HCS bit in ACMD41) extension.

Sign In or Register to comment.