Discussion
Once Papyrix has decided whether it actually wants to boot... It inits SD card access & an SPI bus for it to use, from which it can read (amongst other things) the ebooks you want it to reader.
For my feature-phone at the very least I'll want to store contacts & texting-history on an SD card, though there's other media I'd enjoy storing there too! So I'd likely reuse this code.
On both microcontrollers of interest to me Arduino implements SPI as 2 layers around the hardware's magic pointers.
1/
For the SAMD21 microcontroller I've bought the inner layer of abstraction is shared across most serial protocols, representing shared hardware.
Papyrix includes a support library providing some useful utils wrapping SDFat.h (which I'll explore later), adding error logging via another support library & minimizing how many Stream objects the caller has to juggle.
It includes methods for (de)initialization adding a flag for whether its initialized, recursive directory listings, ...
2/3?
... reads a file entirely into memory a KiB at a time, pipe a file into an output stream in chunks, read a file into caller-specified memory with trailing 0 byte, write a string to a file, create a directory if it doesn't exist with a few retries, open a file by iterating over its parent directory, check if a file exists in that way, some light abstractions upon that, & to delete a directory with all its descendants whilst invoking a callback to render progress.
3/3 Fin! Tomorrow: Logging!
Install bonfire.cafe
Get the full app experience
