Code de demonstration de la lecture des codeurs

CMakeLists.txt

@@ -2,7 +2,7 @@ cmake_minimum_required(VERSION 3.13)
 
 include(pico_sdk_import.cmake)
 
-project(PAMI_Cours_Moteurs C CXX ASM)
+project(PAMI_Cours_Codeurs C CXX ASM)
 set(CMAKE_C_STNDARD 11)
 set(CMAKE_CXX_STANDARD 17)
 
@@ -10,30 +10,33 @@ set(PICO_EXAMPLES_PATH ${PROJECT_SOURCE_DIR})
 
 pico_sdk_init()
 
-add_executable(PAMI_Cours_Moteurs
+add_executable(PAMI_Cours_Codeurs
   main.c
-
   Moteurs.c
+  QEI.c
   Teleplot.c
   Temps.c
 )
 
-target_include_directories(PAMI_Cours_Moteurs PRIVATE ${CMAKE_CURRENT_LIST_DIR})
+pico_generate_pio_header(PAMI_Cours_Codeurs ${CMAKE_CURRENT_LIST_DIR}/quadrature_encoder.pio)
 
-target_link_libraries(PAMI_Cours_Moteurs
-  hardware_uart 
+target_include_directories(PAMI_Cours_Codeurs PRIVATE ${CMAKE_CURRENT_LIST_DIR})
+
+target_link_libraries(PAMI_Cours_Codeurs
+  hardware_uart
+  hardware_pio 
   hardware_pwm 
   pico_stdlib
   pico_multicore
   pico_cyw43_arch_lwip_poll
 )
 
-pico_enable_stdio_usb(PAMI_Cours_Moteurs 1)
-pico_enable_stdio_uart(PAMI_Cours_Moteurs 1)
+pico_enable_stdio_usb(PAMI_Cours_Codeurs 1)
+pico_enable_stdio_uart(PAMI_Cours_Codeurs 1)
 
-pico_add_extra_outputs(PAMI_Cours_Moteurs)
+pico_add_extra_outputs(PAMI_Cours_Codeurs)
 
 add_custom_target(Flash
-    DEPENDS PAMI_Cours_Moteurs
-    COMMAND sudo picotool load -f ${PROJECT_BINARY_DIR}/PAMI_Cours_Moteurs.uf2
+    DEPENDS PAMI_Cours_Codeurs
+    COMMAND sudo picotool load -f ${PROJECT_BINARY_DIR}/PAMI_Cours_Codeurs.uf2
 )

Moteurs.h

@@ -10,6 +10,7 @@ enum t_moteur {
 
 #define MOTEUR_COMMANDE_MAX 25000
 
+
 void Moteur_init(void);
 void Moteur_set_commande(enum t_moteur moteur, int32_t vitesse );
 void Moteur_stop(void);

QEI.c

@@ -0,0 +1,86 @@
+#include <stdio.h>
+#include "pico/stdlib.h"
+#include "hardware/pio.h"
+#include "hardware/timer.h"
+#include "QEI.h"
+#include "quadrature_encoder.pio.h"
+
+
+// C'est ici que se fait la conversion en mm 
+#define IMPULSION_PAR_MM (1.f)
+
+float impulsion_par_mm;
+
+
+struct QEI_t QEI_A, QEI_B;
+
+bool QEI_est_init = false;
+
+PIO pio_QEI = pio0;
+
+
+void QEI_init(){
+    // Initialisation des 3 modules QEI
+    // Chaque module QEI sera dans une machine à état du PIO 0
+    if(!QEI_est_init){
+        // Offset le début du programme
+        // Si ce n'est pas 0, le programme ne marchera pas
+        uint offset = pio_add_program(pio_QEI, &quadrature_encoder_program); 
+        if(offset != 0){
+            printf("PIO init error: offset != 0");
+        }
+        // Initialisation des "machines à états" :
+        // QEI1 : broche 11 et 12 - pio : pio0, sm : 0, Offset : 0, GPIO 11 et 12, clock div : 0 pour commencer
+        quadrature_encoder_program_init(pio_QEI, 0, offset, 11, 0);
+        // QEI2 : broche 2 et 3 - pio : pio0, sm : 1, Offset : 0, GPIO 2 et 3, clock div : 0 pour commencer
+        quadrature_encoder_program_init(pio_QEI, 1, offset, 2, 0);
+
+        QEI_A.value=0;
+        QEI_B.value=0;
+        QEI_est_init=true;
+    }
+    impulsion_par_mm = IMPULSION_PAR_MM;
+}
+
+/// @brief Lit les modules QEI et stock l'écart en cette lecture et la lecture précédente.
+void QEI_update(void){
+    
+    int old_value;
+
+    old_value = QEI_A.value;
+    QEI_A.value = quadrature_encoder_get_count(pio_QEI, 0);
+    QEI_A.delta = QEI_A.value - old_value;
+
+    old_value = QEI_B.value;
+    QEI_B.value = quadrature_encoder_get_count(pio_QEI, 1);
+    QEI_B.delta = QEI_B.value - old_value;
+
+}
+
+/// @brief Renvoi le nombre d'impulsion du module QEI depuis la lecture précédente
+/// Les signe sont inversés (sauf A) car le reducteur inverse le sens de rotation.
+/// Attention, le signe du QEI_A est inversé par rapport aux autres à cause d'un soucis sur la carte électornique
+/// @param  qei : Nom du module à lire (QEI_A_NAME, QEI_B_NAME ou QEI_C_NAME)
+/// @return Nombre d'impulsion calculé lors du dernier appel de la function QEI_Update()
+int QEI_get(enum QEI_name_t qei){
+    switch (qei)
+    {
+    case QEI_A_NAME:
+        return QEI_A.delta;
+        break;
+
+    case QEI_B_NAME:
+        return -QEI_B.delta;
+        break;
+    
+    default:
+        break;
+    }
+}
+
+/// @brief Renvoi la distance parcourue en mm depuis la lecture précédente
+/// @param  qei : Nom du module à lire (QEI_A_NAME, QEI_B_NAME ou QEI_C_NAME)
+/// @return la distance parcourue en mm calculée lors du dernier appel de la function QEI_Update()
+float QEI_get_mm(enum QEI_name_t qei){
+    return ((float) QEI_get(qei)) / impulsion_par_mm;
+}

QEI.h

@@ -0,0 +1,16 @@
+struct QEI_t{
+    int value;
+    int delta;
+};
+
+enum QEI_name_t{
+    QEI_A_NAME=0,
+    QEI_B_NAME=1,
+};
+
+extern struct QEI_t QEI_A, QEI_B, QEI_C;
+
+void QEI_update(void);
+void QEI_init();
+int QEI_get(enum QEI_name_t qei);
+float QEI_get_mm(enum QEI_name_t qei);

main.c

@@ -5,6 +5,7 @@
 */
 #include "pico/stdlib.h"
 #include "Moteurs.h"
+#include "QEI.h"
 #include "Teleplot.h"
 #include "Temps.h"
 #include <stdio.h>
@@ -14,6 +15,7 @@ void setup(void);
 void loop(void);
 
 int valeur = 1;
+uint32_t m_temps_ms;
 
 void main(void)
 {
@@ -28,10 +30,31 @@ void setup(void){
 	Teleplot_init();
 	Temps_init();
 	Moteur_init();
+	QEI_init();
 }
 
 void loop(void){
+	static float cA_distance = 0, cB_distance = 0;
 	float t = (float) Temps_get_temps_ms() / 1000. ;
 	Moteur_set_commande(MOTEUR_A, sin(t * 3.14) * MOTEUR_COMMANDE_MAX) ;
 	Moteur_set_commande(MOTEUR_B, sin(t * 3.14) * MOTEUR_COMMANDE_MAX) ;
+	if(m_temps_ms != Temps_get_temps_ms()){
+		m_temps_ms = Temps_get_temps_ms();
+
+		if(m_temps_ms % 1 == 0){ // Fréquence d'actualisation des codeurs (1 ms)
+			QEI_update();
+			cA_distance += QEI_get_mm(QEI_A_NAME);
+			cB_distance += QEI_get_mm(QEI_B_NAME);
+		}
+
+		if(m_temps_ms % 20 == 0){ // Fréquence d'affichage (20 ms)
+			Teleplot_fige_temps();
+			Teleplot_add_variable_float_2decimal("codeur_A_vitesse", QEI_get_mm(QEI_A_NAME));
+			Teleplot_add_variable_float_2decimal("codeur_B_vitesse", QEI_get_mm(QEI_B_NAME));
+			Teleplot_add_variable_float_2decimal("codeur_A_distance", cA_distance);
+			Teleplot_add_variable_float_2decimal("codeur_B_distance", cA_distance);
+			Teleplot_envoie_tampon();
+		}
+	}
+
 }

quadrature_encoder.pio

@@ -0,0 +1,165 @@
+;
+; Copyright (c) 2021 pmarques-dev @ github
+;
+; SPDX-License-Identifier: BSD-3-Clause
+;
+
+.program quadrature_encoder
+
+; this code must be loaded into address 0, but at 29 instructions, it probably
+; wouldn't be able to share space with other programs anyway
+.origin 0
+
+
+; the code works by running a loop that continuously shifts the 2 phase pins into
+; ISR and looks at the lower 4 bits to do a computed jump to an instruction that
+; does the proper "do nothing" | "increment" | "decrement" action for that pin
+; state change (or no change)
+
+; ISR holds the last state of the 2 pins during most of the code. The Y register
+; keeps the current encoder count and is incremented / decremented according to
+; the steps sampled
+
+; writing any non zero value to the TX FIFO makes the state machine push the
+; current count to RX FIFO between 6 to 18 clocks afterwards. The worst case
+; sampling loop takes 14 cycles, so this program is able to read step rates up
+; to sysclk / 14  (e.g., sysclk 125MHz, max step rate = 8.9 Msteps/sec)
+
+
+; 00 state
+	JMP update	; read 00
+	JMP decrement	; read 01
+	JMP increment	; read 10
+	JMP update	; read 11
+
+; 01 state
+	JMP increment	; read 00
+	JMP update	; read 01
+	JMP update	; read 10
+	JMP decrement	; read 11
+
+; 10 state
+	JMP decrement	; read 00
+	JMP update	; read 01
+	JMP update	; read 10
+	JMP increment	; read 11
+
+; to reduce code size, the last 2 states are implemented in place and become the
+; target for the other jumps
+
+; 11 state
+	JMP update	; read 00
+	JMP increment	; read 01
+decrement:
+	; note: the target of this instruction must be the next address, so that
+	; the effect of the instruction does not depend on the value of Y. The
+	; same is true for the "JMP X--" below. Basically "JMP Y--, <next addr>"
+	; is just a pure "decrement Y" instruction, with no other side effects
+	JMP Y--, update	; read 10
+
+	; this is where the main loop starts
+.wrap_target
+update:
+	; we start by checking the TX FIFO to see if the main code is asking for
+	; the current count after the PULL noblock, OSR will have either 0 if
+	; there was nothing or the value that was there
+	SET X, 0
+	PULL noblock
+
+	; since there are not many free registers, and PULL is done into OSR, we
+	; have to do some juggling to avoid losing the state information and
+	; still place the values where we need them
+	MOV X, OSR
+	MOV OSR, ISR
+
+	; the main code did not ask for the count, so just go to "sample_pins"
+	JMP !X, sample_pins
+
+	; if it did ask for the count, then we push it
+	MOV ISR, Y	; we trash ISR, but we already have a copy in OSR
+	PUSH
+
+sample_pins:
+	; we shift into ISR the last state of the 2 input pins (now in OSR) and
+	; the new state of the 2 pins, thus producing the 4 bit target for the
+	; computed jump into the correct action for this state
+	MOV ISR, NULL
+	IN OSR, 2
+	IN PINS, 2
+	MOV PC, ISR
+
+	; the PIO does not have a increment instruction, so to do that we do a
+	; negate, decrement, negate sequence
+increment:
+	MOV X, !Y
+	JMP X--, increment_cont
+increment_cont:
+	MOV Y, !X
+.wrap	; the .wrap here avoids one jump instruction and saves a cycle too
+
+
+
+% c-sdk {
+
+#include "hardware/clocks.h"
+#include "hardware/gpio.h"
+
+// max_step_rate is used to lower the clock of the state machine to save power
+// if the application doesn't require a very high sampling rate. Passing zero
+// will set the clock to the maximum, which gives a max step rate of around
+// 8.9 Msteps/sec at 125MHz
+
+static inline void quadrature_encoder_program_init(PIO pio, uint sm, uint offset, uint pin, int max_step_rate)
+{
+	pio_sm_set_consecutive_pindirs(pio, sm, pin, 2, false);
+	gpio_pull_up(pin);
+	gpio_pull_up(pin + 1);
+
+	pio_sm_config c = quadrature_encoder_program_get_default_config(offset);
+	sm_config_set_in_pins(&c, pin); // for WAIT, IN
+	sm_config_set_jmp_pin(&c, pin); // for JMP
+	// shift to left, autopull disabled
+	sm_config_set_in_shift(&c, false, false, 32);
+	// don't join FIFO's
+	sm_config_set_fifo_join(&c, PIO_FIFO_JOIN_NONE);
+
+	// passing "0" as the sample frequency,
+	if (max_step_rate == 0) {
+		sm_config_set_clkdiv(&c, 1.0);
+	} else {
+		// one state machine loop takes at most 14 cycles
+		float div = (float)clock_get_hz(clk_sys) / (14 * max_step_rate);
+		sm_config_set_clkdiv(&c, div);
+	}
+
+	pio_sm_init(pio, sm, offset, &c);
+	pio_sm_set_enabled(pio, sm, true);
+}
+
+
+// When requesting the current count we may have to wait a few cycles (average
+// ~11 sysclk cycles) for the state machine to reply. If we are reading multiple
+// encoders, we may request them all in one go and then fetch them all, thus
+// avoiding doing the wait multiple times. If we are reading just one encoder,
+// we can use the "get_count" function to request and wait
+
+static inline void quadrature_encoder_request_count(PIO pio, uint sm)
+{
+	pio->txf[sm] = 1;
+}
+
+static inline int32_t quadrature_encoder_fetch_count(PIO pio, uint sm)
+{
+	while (pio_sm_is_rx_fifo_empty(pio, sm))
+		tight_loop_contents();
+	return pio->rxf[sm];
+}
+
+static inline int32_t quadrature_encoder_get_count(PIO pio, uint sm)
+{
+	quadrature_encoder_request_count(pio, sm);
+	return quadrature_encoder_fetch_count(pio, sm);
+}
+
+%}
+