Datasheet


NOTE
Within the Pico SDK you do not need to invoke pioasm directly, as the CMake function pico_generate_pio_header(TARGET
PIO_FILE) takes care of invoking pioasm and adding the generated header to the include path of the target TARGET for
you.
3.3.2. Directives
The following directives control the assembly of PIO programs:
Table 356. pioasm
directives
.define ( PUBLIC ) <symbol> <value> Define an integer symbol named <symbol> with the value <value> (see Section
3.3.3). If this .define appears before the first program in the input file, then the
define is global to all programs, otherwise it is local to the program in which it
occurs. If PUBLIC is specified the symbol will be emitted into the assembled
output for use by user code. For the Pico SDK this takes the form of:
#define <program_name>_<symbol> value for program symbols or #define <symbol>
value for global symbols
.program <name> Start a new program with the name <name>. Note that that name is used in
code so should be alphanumeric/underscore not starting with a digit. The
program lasts until another .program directive or the end of the source file. PIO
instructions are only allowed within a program
.origin <offset> Optional directive to speicfy the PIO instruction memory offset at which the
program must load. Most commonly this is used for programs that must load
at offset 0, because they use data based JMPs with the (absolute) jmp target
being stored in only a few bits. This directive is invalid outside of a program
.side_set <count> (opt) (pindirs) If this directive is present, <count> indicates the number of side set bits to be
used. Additionally opt may be specified to indicate that a side <value> is
optional for instructions (not using this requires stealing an extra bit - in addition
to the <count> bits - from those available for the instruction delay). Finally,
pindirs may be specified to indicate that the side set values should be applied to
the PINDIRs and not the PINs. This directive is only valid within a program
before the first instruction
.wrap_target Place prior to an instruction, this directive specifies the instruction where
execution continues due to program wrapping. This directive is invalid outside
of a program, may only be used once within a program, and if not specified
defaults to the start of the program
.wrap Placed after an instruction, this directive specifies the instruction after which, in
normal control flow, the program wraps (to .wrap_target instruction). This
directive is invalid outside of a program, may only be used once within a
program, and if not specified defaults to after the last program instruction.
.lang_opt <lang> <name> <option> Specifies an option for the program related to a particular language generator.
(See Section 3.3.9). This directive is invalid outside of a program
.word <value> Stores a raw 16 bit value as an instruction in the program. This directive is
invalid outside of a program.
3.3.3. Values
The following types of values can be used to define integer numbers or branch targets
RP2040 Datasheet
3.3. PIO Assembler (pioasm) 314