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 static int8_t   ao_quadrature_raw[AO_QUADRATURE_COUNT];
  27
  28 #define BIT(a,b)        ((a) | ((b) << 1))
  29 #define STATE(old_a, old_b, new_a, new_b)       (((BIT(old_a, old_b) << 2) | BIT(new_a, new_b)))
  30
  31 #define port(q) AO_QUADRATURE_ ## q ## _PORT
  32 #define bita(q) AO_QUADRATURE_ ## q ## _A
  33 #define bitb(q) AO_QUADRATURE_ ## q ## _B
  34 #define pina(q) AO_QUADRATURE_ ## q ## _A ## _PIN
  35 #define pinb(q) AO_QUADRATURE_ ## q ## _B ## _PIN
  36 #define isr(q)  ao_quadrature_isr_ ## q
  37
  38 static inline uint16_t
  39 ao_quadrature_read(struct stm_gpio *gpio, uint8_t pin_a, uint8_t pin_b) {
  40         uint16_t        v = stm_gpio_get_all(gpio);
  41
  42         return ~((((v >> pin_a) & 1) | (((v >> pin_b) & 1) << 1))) & 3;
  43 }
  44
  45 #define _ao_quadrature_get(q)   ao_quadrature_read(port(q), bita(q), bitb(q))
  46
  47 static void
  48 _ao_quadrature_queue(uint8_t q, int8_t step)
  49 {
  50         ao_quadrature_count[q] += step;
  51 #if AO_EVENT
  52         ao_event_put_isr(AO_EVENT_QUADRATURE, q, step);
  53 #endif
  54         ao_wakeup(&ao_quadrature_count[q]);
  55 }
  56
  57 static const int8_t     step[16] = {
  58         [STATE(0,0,0,0)] = 0,
  59         [STATE(0,0,0,1)] = -1,
  60         [STATE(0,0,1,0)] = 1,
  61         [STATE(0,0,1,1)] = 0,
  62         [STATE(0,1,0,0)] = 1,
  63         [STATE(0,1,1,0)] = 0,
  64         [STATE(0,1,1,1)] = -1,
  65         [STATE(1,0,0,0)] = -1,
  66         [STATE(1,0,0,1)] = 0,
  67         [STATE(1,0,1,0)] = 0,
  68         [STATE(1,0,1,1)] = 1,
  69         [STATE(1,1,0,0)] = 0,
  70         [STATE(1,1,0,1)] = 1,
  71         [STATE(1,1,1,0)] = -1,
  72         [STATE(1,1,1,1)] = 0
  73 };
  74
  75 static void
  76 _ao_quadrature_set(uint8_t q, uint8_t value) {
  77         uint8_t v;
  78
  79         v = ao_quadrature_state[q] & 3;
  80         value = value & 3;
  81
  82         if (v == value)
  83                 return;
  84
  85         ao_quadrature_state[q] = (v << 2) | value;
  86
  87         ao_quadrature_raw[q] += step[ao_quadrature_state[q]];
  88         if (value == 0) {
  89                 if (ao_quadrature_raw[q] == 4)
  90                         _ao_quadrature_queue(q, 1);
  91                 else if (ao_quadrature_raw[q] == -4)
  92                         _ao_quadrature_queue(q, -1);
  93                 ao_quadrature_raw[q] = 0;
  94         }
  95 }
  96
  97 static void
  98 ao_quadrature_isr(void)
  99 {
 100         _ao_quadrature_set(0, _ao_quadrature_get(0));
 101         _ao_quadrature_set(1, _ao_quadrature_get(1));
 102 }
 103
 104 int32_t
 105 ao_quadrature_poll(uint8_t q)
 106 {
 107         int32_t ret;
 108         ao_arch_critical(ret = ao_quadrature_count[q];);
 109         return ret;
 110 }
 111
 112 int32_t
 113 ao_quadrature_wait(uint8_t q)
 114 {
 115         ao_sleep(&ao_quadrature_count[q]);
 116         return ao_quadrature_poll(q);
 117 }
 118
 119 static void
 120 ao_quadrature_test(void)
 121 {
 122         uint8_t q;
 123
 124         ao_cmd_decimal();
 125         q = ao_cmd_lex_i;
 126         if (q >= AO_QUADRATURE_COUNT) {
 127                 ao_cmd_status = ao_cmd_syntax_error;
 128                 return;
 129         }
 130         printf ("count %d state %x raw %d\n",
 131                 ao_quadrature_count[q],
 132                 ao_quadrature_state[q],
 133                 ao_quadrature_raw[q]);
 134 #if 0
 135         for (;;) {
 136                 int32_t c;
 137                 flush();
 138                 c = ao_quadrature_wait(q);
 139                 printf ("new count %6d\n", c);
 140                 if (c == 100)
 141                         break;
 142         }
 143 #endif
 144 }
 145
 146 static const struct ao_cmds ao_quadrature_cmds[] = {
 147         { ao_quadrature_test,   "q <unit>\0Test quadrature" },
 148         { 0, NULL }
 149 };
 150
 151 #define init(q) do {                                    \
 152                 ao_enable_input(port(q), bita(q), 0);   \
 153                 ao_enable_input(port(q), bitb(q), 0);   \
 154         } while (0)
 155
 156 void
 157 ao_quadrature_init(void)
 158 {
 159 #if AO_QUADRATURE_COUNT > 0
 160         init(0);
 161 #endif
 162 #if AO_QUADRATURE_COUNT > 1
 163         init(1);
 164 #endif
 165         ao_fast_timer_init();
 166         ao_fast_timer_on(ao_quadrature_isr);
 167         ao_cmd_register(&ao_quadrature_cmds[0]);
 168 }