git.gag.com Git - fw/altos/blob - src/drivers/ao_quadrature.c

   1 /*
   2  * Copyright © 2012 Keith Packard <keithp@keithp.com>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful, but
  10  * WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License along
  15  * with this program; if not, write to the Free Software Foundation, Inc.,
  16  * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
  17  */
  18
  19 #include <ao.h>
  20 #include <ao_quadrature.h>
  21 #include <ao_exti.h>
  22 #include <ao_fast_timer.h>
  23 #include <ao_event.h>
  24
  25 __xdata int32_t ao_quadrature_count[AO_QUADRATURE_COUNT];
  26 #ifndef AO_QUADRATURE_SINGLE_CODE
  27 static int8_t ao_quadrature_step[AO_QUADRATURE_COUNT];
  28 #endif
  29
  30 static uint8_t  ao_quadrature_state[AO_QUADRATURE_COUNT];
  31
  32 struct ao_debounce {
  33         uint8_t state;
  34         uint8_t count;
  35 };
  36
  37 static struct ao_debounce ao_debounce_state[AO_QUADRATURE_COUNT][2];
  38
  39 #define port(q) AO_QUADRATURE_ ## q ## _PORT
  40 #define bita(q) AO_QUADRATURE_ ## q ## _A
  41 #define bitb(q) AO_QUADRATURE_ ## q ## _B
  42 #define pina(q) AO_QUADRATURE_ ## q ## _A ## _PIN
  43 #define pinb(q) AO_QUADRATURE_ ## q ## _B ## _PIN
  44 #define isr(q)  ao_quadrature_isr_ ## q
  45
  46 #ifndef AO_QUADRATURE_DEBOUNCE
  47 #error must define AO_QUADRATURE_DEBOUNCE
  48 #endif
  49
  50 static uint8_t
  51 ao_debounce(uint8_t cur, struct ao_debounce *debounce)
  52 {
  53 #if AO_QUADRATURE_DEBOUNCE > 0
  54         if (debounce->count > 0) {
  55                 debounce->count--;
  56         } else if (cur != debounce->state) {
  57                 debounce->state = cur;
  58                 debounce->count = AO_QUADRATURE_DEBOUNCE;
  59         }
  60         return debounce->state;
  61 #else
  62         (void) debounce;
  63         return cur;
  64 #endif
  65 }
  66
  67 static uint16_t
  68 ao_quadrature_read(struct stm_gpio *gpio, uint8_t pin_a, uint8_t pin_b, struct ao_debounce debounce_state[2]) {
  69         uint16_t        v = ~stm_gpio_get_all(gpio);
  70         uint8_t         a = (v >> pin_a) & 1;
  71         uint8_t         b = (v >> pin_b) & 1;
  72
  73         a = ao_debounce(a, &debounce_state[0]);
  74         b = ao_debounce(b, &debounce_state[1]);
  75
  76         return a | (b << 1);
  77 }
  78
  79 #define _ao_quadrature_get(q)   ao_quadrature_read(port(q), bita(q), bitb(q), ao_debounce_state[q])
  80
  81 static void
  82 _ao_quadrature_step(uint8_t q, int8_t step)
  83 {
  84 #ifndef AO_QUADRATURE_SINGLE_CODE
  85         ao_quadrature_step[q] += step;
  86         if (ao_quadrature_state[q] != 0)
  87                 return;
  88         if (ao_quadrature_step[q] >= 4) {
  89                 ao_quadrature_step[q] = 0;
  90                 step = 1;
  91         } else if (ao_quadrature_step[q] <= -4) {
  92                 ao_quadrature_step[q] = 0;
  93                 step = -1;
  94         } else
  95                 return;
  96 #endif
  97         ao_quadrature_count[q] += step;
  98 #if AO_EVENT
  99         ao_event_put_isr(AO_EVENT_QUADRATURE, q, step);
 100 #endif
 101         ao_wakeup(&ao_quadrature_count[q]);
 102 }
 103
 104 static const struct {
 105         uint8_t prev, next;
 106 } ao_quadrature_steps[4] = {
 107         [0] { .prev = 2, .next = 1 },
 108         [1] { .prev = 0, .next = 3 },
 109         [3] { .prev = 1, .next = 2 },
 110         [2] { .prev = 3, .next = 0 },
 111 };
 112
 113 static void
 114 _ao_quadrature_set(uint8_t q, uint8_t new) {
 115         uint8_t old;
 116
 117         ao_arch_block_interrupts();
 118         old = ao_quadrature_state[q];
 119         ao_quadrature_state[q] = new;
 120         ao_arch_release_interrupts();
 121
 122         if (new == ao_quadrature_steps[old].next)
 123                 _ao_quadrature_step(q, 1);
 124         else if (new == ao_quadrature_steps[old].prev)
 125                 _ao_quadrature_step(q, -1);
 126 }
 127
 128 static void
 129 ao_quadrature_isr(void)
 130 {
 131 #if AO_QUADRATURE_COUNT > 0
 132         _ao_quadrature_set(0, _ao_quadrature_get(0));
 133 #endif
 134 #if AO_QUADRATURE_COUNT > 1
 135         _ao_quadrature_set(1, _ao_quadrature_get(1));
 136 #endif
 137 }
 138
 139 int32_t
 140 ao_quadrature_poll(uint8_t q)
 141 {
 142         int32_t ret;
 143         ao_arch_critical(ret = ao_quadrature_count[q];);
 144         return ret;
 145 }
 146
 147 int32_t
 148 ao_quadrature_wait(uint8_t q)
 149 {
 150         ao_sleep(&ao_quadrature_count[q]);
 151         return ao_quadrature_poll(q);
 152 }
 153
 154 static void
 155 ao_quadrature_test(void)
 156 {
 157         uint8_t q;
 158         int32_t c;
 159         uint8_t s;
 160 #ifndef AO_QUADRATURE_SINGLE_CODE
 161         int8_t t = 0;
 162 #endif
 163
 164         ao_cmd_decimal();
 165         q = ao_cmd_lex_i;
 166         if (q >= AO_QUADRATURE_COUNT)
 167                 ao_cmd_status = ao_cmd_syntax_error;
 168         if (ao_cmd_status != ao_cmd_success)
 169                 return;
 170
 171         c = -10000;
 172         s = 0;
 173         while (ao_quadrature_count[q] != 10) {
 174                 if (ao_quadrature_count[q] != c ||
 175 #ifndef AO_QUADRATURE_SINGLE_CODE
 176                     ao_quadrature_step[q] != t ||
 177 #endif
 178                     ao_quadrature_state[q] != s)
 179                 {
 180                         c = ao_quadrature_count[q];
 181                         s = ao_quadrature_state[q];
 182 #ifndef AO_QUADRATURE_SINGLE_CODE
 183                         t = ao_quadrature_step[q];
 184                         printf("step %3d ", t);
 185 #endif
 186                         printf ("count %3d state %2x\n", c, s);
 187                         flush();
 188                 }
 189         }
 190 #if 0
 191         for (;;) {
 192                 int32_t c;
 193                 flush();
 194                 c = ao_quadrature_wait(q);
 195                 printf ("new count %6d\n", c);
 196                 if (c == 100)
 197                         break;
 198         }
 199 #endif
 200 }
 201
 202 static const struct ao_cmds ao_quadrature_cmds[] = {
 203         { ao_quadrature_test,   "q <unit>\0Test quadrature" },
 204         { 0, NULL }
 205 };
 206
 207 #define init(q) do {                                    \
 208                 ao_enable_input(port(q), bita(q), 0);   \
 209                 ao_enable_input(port(q), bitb(q), 0);   \
 210         } while (0)
 211
 212 void
 213 ao_quadrature_init(void)
 214 {
 215 #if AO_QUADRATURE_COUNT > 0
 216         init(0);
 217 #endif
 218 #if AO_QUADRATURE_COUNT > 1
 219         init(1);
 220 #endif
 221         ao_fast_timer_init();
 222         ao_fast_timer_on(ao_quadrature_isr);
 223         ao_cmd_register(&ao_quadrature_cmds[0]);
 224 }