#include "hardware/pio.h"
#include <assert.h>
#include <stddef.h>
#include "hardware/clocks.h"
#include "hardware/structs/clocks.h"
#include "hx711.h"

Macros
#define	hx711_reader_wrap_target 3

#define	hx711_reader_wrap 13

#define	hx711_reader_HZ 10000000

Functions
static pio_sm_config	hx711_reader_program_get_default_config (uint offset)

void	hx711_reader_pio_init (hx711_t *const hx)

void	hx711_reader_program_init (hx711_t *const hx)

Variables
static const uint16_t	hx711_reader_program_instructions []

static const struct pio_program	hx711_reader_program

Macro Definition Documentation

◆ hx711_reader_HZ

#define hx711_reader_HZ 10000000

Definition at line 18 of file hx711_reader.pio.h.

◆ hx711_reader_wrap

#define hx711_reader_wrap 13

Definition at line 16 of file hx711_reader.pio.h.

◆ hx711_reader_wrap_target

#define hx711_reader_wrap_target 3

Definition at line 15 of file hx711_reader.pio.h.

Function Documentation

◆ hx711_reader_pio_init()

void hx711_reader_pio_init ( hx711_t *const hx )

Definition at line 80 of file hx711_reader.pio.h.

                                               {
     assert(hx != NULL);
     assert(hx->_pio != NULL);
     pio_gpio_init(
         hx->_pio,
         hx->_clock_pin);
     //clock pin setup
     pio_sm_set_out_pins(
         hx->_pio,
         hx->_reader_sm,
         hx->_clock_pin,
         1);
     pio_sm_set_set_pins(
         hx->_pio,
         hx->_reader_sm,
         hx->_clock_pin,
         1);
     pio_sm_set_consecutive_pindirs(
         hx->_pio,
         hx->_reader_sm,
         hx->_clock_pin,
         1,
         true);
     //data pin setup
     pio_gpio_init(
         hx->_pio,
         hx->_data_pin);
     pio_sm_set_in_pins(
         hx->_pio,
         hx->_reader_sm,
         hx->_data_pin);
     pio_sm_set_consecutive_pindirs(
         hx->_pio,
         hx->_reader_sm,
         hx->_data_pin,
         1,
         false);
 }

References hx711_t::_clock_pin, hx711_t::_data_pin, hx711_t::_pio, and hx711_t::_reader_sm.

◆ hx711_reader_program_get_default_config()

static pio_sm_config hx711_reader_program_get_default_config ( uint offset )

inlinestatic

Definition at line 46 of file hx711_reader.pio.h.

                                                                                  {
     pio_sm_config c = pio_get_default_sm_config();
     sm_config_set_wrap(&c, offset + hx711_reader_wrap_target, offset + hx711_reader_wrap);
     sm_config_set_sideset(&c, 2, true, false);
     return c;
 }

References hx711_reader_wrap, and hx711_reader_wrap_target.

Referenced by hx711_reader_program_init().

◆ hx711_reader_program_init()

void hx711_reader_program_init ( hx711_t *const hx )

Why enable autopush?

"The state machine keeps an eye on the total amount of data shifted into the ISR, and on the in which reaches or breaches a total shift count of 32 (or whatever number you have configured), the ISR contents, along with the new data from the in. goes straight to the RX FIFO. The ISR is cleared to zero in the same operation."

Raspberry Pi Pico C/C++ SDK pg. 45

When manually pushing using noblock, the FIFO contents are NOT changed.

"The PIO assembler sets the Block bit by default. If the Block bit is not set, the PUSH does not stall on a full RX FIFO, instead continuing immediately to the next instruction. The FIFO state and contents are unchanged when this happens. The ISR is still cleared to all-zeroes, and the FDEBUG_RXSTALL flag is set (the same as a blocking PUSH or autopush to a full RX FIFO) to indicate data was lost."

Raspberry Pi Pico C/C++ SDK pg. 64

Manually pushing is not ideal. Application code should be able to look at the FIFO and assume that the value inside is the most up-to-date data available. Autopushing does this.

Definition at line 118 of file hx711_reader.pio.h.

                                                   {
     assert(hx != NULL);
     assert(hx->_pio != NULL);
     pio_sm_config cfg = hx711_reader_program_get_default_config(
         hx->_reader_offset);
     const float div = (float)(clock_get_hz(clk_sys)) / (uint)hx711_reader_HZ;
     sm_config_set_clkdiv(
         &cfg,
         div);
     sm_config_set_set_pins(
         &cfg,
         hx->_clock_pin,
         1);
     sm_config_set_out_pins(
         &cfg,
         hx->_clock_pin,
         1);
     sm_config_set_sideset_pins(
         &cfg,
         hx->_clock_pin);
     sm_config_set_in_pins(
         &cfg,
         hx->_data_pin);
     sm_config_set_in_shift(
         &cfg,
         false,            //false = shift in left
         true,             //true = autopush enabled
         HX711_READ_BITS); //autopush on 24 bits
     pio_sm_clear_fifos(
         hx->_pio,
         hx->_reader_sm);
     //store a copy of the configuration for resetting the sm
     hx->_reader_prog_default_config = cfg;
 }

References hx711_t::_clock_pin, hx711_t::_data_pin, hx711_t::_pio, hx711_t::_reader_offset, hx711_t::_reader_prog_default_config, hx711_t::_reader_sm, HX711_READ_BITS, hx711_reader_HZ, and hx711_reader_program_get_default_config().

Variable Documentation

◆ hx711_reader_program

const struct pio_program hx711_reader_program

static

Initial value:

= {
    .instructions = hx711_reader_program_instructions,
    .length = 14,
    .origin = -1,
}

Definition at line 20 of file hx711_reader.pio.h.

◆ hx711_reader_program_instructions

const uint16_t hx711_reader_program_instructions[]