board/progmem

This is documentation for the progmem integration. Please note that this is just documentation for the interface, different boards might have different caveats for the various procedures.

type Progmem[T] = distinct T

Type for data stored in program memory, accesing this memory should trigger the correct behaviour for reading this data. If this is not a useful distinction on the selected board it will simply behave as the normal type.

type ProgmemString[size] = Progmem[array[size, char]]

Special type for strings stored in program memory.

proc pgmReadByte[T](address: ptr T): uint8

Low level procedure for reading a single byte of program memory

proc pgmReadWord[T](address: ptr T): uint16

Low level procedure for reading a two-byte word of program memory

proc pgmReadDoubleWord[T](address: ptr T): uint32

Low level procedure for reading a four-byte double word of program memory

proc memcpyPgm[T](dest: ptr T; src: ptr T; size: csize_t): ptr T

Low level procedure for reading arbitrary amounts of data from program memory

proc `[]`[T](src: ptr Progmem[T]): T

Dereference operator for program memory, this will read all the memory indendpented of the size of the underlying type.

template `[]`[N, T](data: Progmem[array[N, T]]; idx: int): untyped

Array access for program memory allocated arrays. This will either return a progmem type for whatever is stored in the array, or simply read out the value depending on whether it's a simply type or an object.

template `[]`(data: Progmem[cstring]; idx: int): untyped

Reads a single character from a cstring stored in program memory, this does not verify if idx is actually within the string.

proc readInto[T](dst: var T; src: Progmem[T])

Reads progmem data into a variable

template read[T](data: Progmem[T]): T

Creates a read statement for the progmem data

template len[N, T](data: Progmem[array[N, T]]): untyped

Returns the length of an array in program memory

template p(x: static[string]): untyped

Template to turn string literals into program memory strings. Analagous to the F macro in Arduino. Simply call it like this:

serial.send p"Hello world"

macro progmem(definitions: untyped): untyped

Creates a block in which you can define variables which will be stored in program memory.