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