P2 Dual uSD FAT32 and FLASH FS

A unified filesystem driver for the Parallax Propeller 2 (P2) that provides simultaneous access to both the onboard 16MB FLASH chip and a microSD card through a single cog and a single API.

When to Use This Driver

This driver is larger than either standalone driver because it includes both filesystems. There are several ways to use it depending on your project needs:

• Dual-device product — Your application uses both SD and Flash at runtime. One cog, one API, both devices always available.

• Provisioning tool — Use the SD card to load configuration files, firmware images, or data onto Flash during manufacturing or field setup. Once Flash is populated, ship the product with the smaller standalone Flash driver for a reduced image size.

• Development and testing — Use the SD card as a convenient way to get data onto the board during development, then switch to Flash-only for production.

If your product only ever needs one device, the standalone drivers (Flash-only, SD-only) produce smaller binaries.

Features

• One worker cog, two devices — a dedicated cog owns all SPI I/O for both SD and Flash, eliminating bus contention
• Unified API — mount, open, read, write, close, and copy files on either device with the same calls
• Cross-device copy — copy files between Flash and SD through one driver with copyFile()
• Shared SPI bus management — automatic bus switching between SD (Mode 0) and Flash (Mode 3) with proper smart pin reconfiguration
• Flash directory emulation — per-cog current working directory on the flat Flash filesystem using slash-delimited filename convention
• Multi-cog safety — hardware lock serializes access from up to 8 cogs
• Defragmentation — query file fragmentation, compact files in-place, create pre-allocated contiguous files (SD_INCLUDE_DEFRAG)
• Conditional compilation — SD_INCLUDE_RAW, SD_INCLUDE_REGISTERS, SD_INCLUDE_SPEED, SD_INCLUDE_DEBUG, SD_INCLUDE_DEFRAG for minimal or full builds
• 1,350 regression tests across 32 standard test suites verified on real P2 hardware

Hardware Requirements

• Parallax Propeller 2 — P2-EC or P2-EC32MB
• microSD card (SDHC or SDXC) — the included format utility can format cards that are not already FAT32

Notes

• This is a regression test certified driver for the P2 Edge boards.
  This object v1.3.0 will be updated periodically. For the latest release, visit the Releases Page