Raspberry Pi Pico - Details

20: UART1 TX
21: UART1 RX
There is one line in the setup_default_uart function:
bi_decl_if_func_used(bi_2pins_with_func(PICO_DEFAULT_UART_RX_PIN, PICO_DEFAULT_UART_TX_PIN,
GPIO_FUNC_UART));
The two pin numbers, and the function UART are stored, then decoded to their actual function names (UART1 TX etc) by
picotool. The bi_decl_if_func_used makes sure the binary information is only included if the containing function is called.
Equally, the video code contains a few lines like this:
bi_decl_if_func_used(bi_pin_mask_with_name(0x1f << (PICO_SCANVIDEO_COLOR_PIN_BASE +
PICO_SCANVIDEO_DPI_PIXEL_RSHIFT), "Red 0-4"));
Details
Things are designed to waste as little space as possible, but you can turn everything off with preprocessor var
PICO_NO_BINARY_INFO=1. Additionally any SDK code that inserts binary info can be separately excluded by its own
preprocesor var.
You need,
#include "pico/binary_info.h"
There are a bunch of bi_ macros in the headers
#define bi_binary_end(end)
#define bi_program_name(name)
#define bi_program_description(description)
#define bi_program_version_string(version_string)
#define bi_program_build_date_string(date_string)
#define bi_program_url(url)
#define bi_program_feature(feature)
#define bi_program_build_attribute(attr)
#define bi_1pin_with_func(p0, func)
#define bi_2pins_with_func(p0, p1, func)
#define bi_3pins_with_func(p0, p1, p2, func)
#define bi_4pins_with_func(p0, p1, p2, p3, func)
#define bi_5pins_with_func(p0, p1, p2, p3, p4, func)
#define bi_pin_range_with_func(plo, phi, func)
#define bi_pin_mask_with_name(pmask, label)
#define bi_pin_mask_with_names(pmask, label)
#define bi_1pin_with_name(p0, name)
#define bi_2pins_with_names(p0, name0, p1, name1)
#define bi_3pins_with_names(p0, name0, p1, name1, p2, name2)
#define bi_4pins_with_names(p0, name0, p1, name1, p2, name2, p3, name3)
which make use of underlying macros, e.g.
Getting started with Raspberry Pi Pico
Binary Information 71