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Updates along with SDK1.3.0 release (#181)

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Bug fixes and new examples

Co-authored-by: Paulo Marques <pm@quant-insight.com>
Co-authored-by: martin <admin@crossleys.biz>
Co-authored-by: matiasilva <matias.silva@raspberrypi.com>
Co-authored-by: Uri Shaked <uri@urishaked.com>
Co-authored-by: Diego Solano <diegosolano@gmail.com>
Co-authored-by: Andrew Scheller <andrew.scheller@raspberrypi.com>
Co-authored-by: Adrian Hesketh <a-h@users.noreply.github.com>
Co-authored-by: Emircan Gündoğdu <58917386+emircangun@users.noreply.github.com>
Co-authored-by: Josef Wegner <80200012+josefwegner@users.noreply.github.com>
Co-authored-by: pmarques-dev <72901351+pmarques-dev@users.noreply.github.com>
Co-authored-by: Paulo Marques <pm@quant-insight.com>
Co-authored-by: mjcross <mjcross@users.noreply.github.com>
Co-authored-by: martin <admin@crossleys.biz>
This commit is contained in:
Graham Sanderson
2021-11-01 14:41:54 -05:00
committed by GitHub
parent 146680d625
commit f800a7e303
150 changed files with 4832 additions and 98 deletions
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61
pio/quadrature_encoder/quadrature_encoder.c Normal file
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/**
* Copyright (c) 2021 pmarques-dev @ github
*
* SPDX-License-Identifier: BSD-3-Clause
*/
#include <stdio.h>
#include "pico/stdlib.h"
#include "hardware/pio.h"
#include "hardware/timer.h"
#include "quadrature_encoder.pio.h"
//
// ---- quadrature encoder interface example
//
// the PIO program reads phase A/B of a quadrature encoder and increments or
// decrements an internal counter to keep the current absolute step count
// updated. At any point, the main code can query the current count by using
// the quadrature_encoder_*_count functions. The counter is kept in a full
// 32 bit register that just wraps around. Two's complement arithmetic means
// that it can be interpreted as a 32-bit signed or unsigned value, and it will
// work anyway.
//
// As an example, a two wheel robot being controlled at 100Hz, can use two
// state machines to read the two encoders and in the main control loop it can
// simply ask for the current encoder counts to get the absolute step count. It
// can also subtract the values from the last sample to check how many steps
// each wheel as done since the last sample period.
//
// One advantage of this approach is that it requires zero CPU time to keep the
// encoder count updated and because of that it supports very high step rates.
//
int main() {
int new_value, delta, old_value = 0;
// Base pin to connect the A phase of the encoder.
// The B phase must be connected to the next pin
const uint PIN_AB = 10;
stdio_init_all();
PIO pio = pio0;
const uint sm = 0;
uint offset = pio_add_program(pio, &quadrature_encoder_program);
quadrature_encoder_program_init(pio, sm, offset, PIN_AB, 0);
while (1) {
// note: thanks to two's complement arithmetic delta will always
// be correct even when new_value wraps around MAXINT / MININT
new_value = quadrature_encoder_get_count(pio, sm);
delta = new_value - old_value;
old_value = new_value;
printf("position %8d, delta %6d\n", new_value, delta);
sleep_ms(100);
}
}