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   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
  22 __xdata int32_t ao_quadrature_count[AO_QUADRATURE_COUNT];
  23
  24 static uint8_t  ao_quadrature_state[AO_QUADRATURE_COUNT];
  25
  26 #define BIT(a,b)        ((a) | ((b) << 1))
  27 #define STATE(old_a, old_b, new_a, new_b)       (((BIT(old_a, old_b) << 2) | BIT(new_a, new_b)))
  28
  29 #define port(q) AO_QUADRATURE_ ## q ## _PORT
  30 #define bita(q) AO_QUADRATURE_ ## q ## _A
  31 #define bitb(q) AO_QUADRATURE_ ## q ## _B
  32
  33 #define ao_quadrature_update(q) do {                                    \
  34                 ao_quadrature_state[q] = ((ao_quadrature_state[q] & 3) << 2); \
  35                 ao_quadrature_state[q] |= ao_gpio_get(port(q), bita(q), 0); \
  36                 ao_quadrature_state[q] |= ao_gpio_get(port(q), bitb(q), 0) << 1; \
  37         } while (0)
  38
  39
  40 static void
  41 ao_quadrature_isr(void)
  42 {
  43         uint8_t q;
  44 #if AO_QUADRATURE_COUNT > 0
  45         ao_quadrature_update(0);
  46 #endif
  47 #if AO_QUADRATURE_COUNT > 1
  48         ao_quadrature_update(1);
  49 #endif
  50
  51         for (q = 0; q < AO_QUADRATURE_COUNT; q++) {
  52                 switch (ao_quadrature_state[q]) {
  53                 case STATE(0, 1, 0, 0):
  54                         ao_quadrature_count[q]++;
  55                         break;
  56                 case STATE(1, 0, 0, 0):
  57                         ao_quadrature_count[q]--;
  58                         break;
  59                 default:
  60                         continue;
  61                 }
  62                 ao_wakeup(&ao_quadrature_count[q]);
  63         }
  64 }
  65
  66 int32_t
  67 ao_quadrature_poll(uint8_t q)
  68 {
  69         int32_t ret;
  70         ao_arch_critical(ret = ao_quadrature_count[q];);
  71         return ret;
  72 }
  73
  74 int32_t
  75 ao_quadrature_wait(uint8_t q)
  76 {
  77         ao_sleep(&ao_quadrature_count[q]);
  78         return ao_quadrature_poll(q);
  79 }
  80
  81 static void
  82 ao_quadrature_test(void)
  83 {
  84 #if 1
  85         for (;;) {
  86                 int32_t c;
  87                 flush();
  88                 c = ao_quadrature_wait(0);
  89                 printf ("new count %6d\n", c);
  90                 if (c == 100)
  91                         break;
  92         }
  93 #endif
  94 #if 0
  95         uint8_t a, old_a, b, old_b;
  96
  97         old_a = 2; old_b = 2;
  98         for (;;) {
  99                 a = ao_gpio_get(AO_QUADRATURE_PORT, AO_QUADRATURE_A, AO_QUADRATURE_A_PIN);
 100                 b = ao_gpio_get(AO_QUADRATURE_PORT, AO_QUADRATURE_B, AO_QUADRATURE_B_PIN);
 101                 if (a != old_a || b != old_b) {
 102                         printf ("A %d B %d count %ld\n", a, b, ao_quadrature_count);
 103                         flush();
 104                         ao_yield();
 105                         old_a = a;
 106                         old_b = b;
 107                 }
 108                 if (ao_stdin_ready)
 109                         break;
 110         }
 111 #endif
 112 }
 113
 114 static const struct ao_cmds ao_quadrature_cmds[] = {
 115         { ao_quadrature_test,   "q\0Test quadrature" },
 116         { 0, NULL }
 117 };
 118
 119 #define init(q) do {                                                    \
 120                 ao_enable_port(port(q));                                \
 121                                                                         \
 122                 ao_exti_setup(port(q), bita(q),                         \
 123                               AO_QUADRATURE_MODE|AO_EXTI_MODE_FALLING|AO_EXTI_MODE_RISING|AO_EXTI_PRIORITY_MED, \
 124                               ao_quadrature_isr);                       \
 125                 ao_exti_enable(port(q), bita(q));                       \
 126                                                                         \
 127                 ao_exti_setup(port(q), bitb(q),                         \
 128                               AO_QUADRATURE_MODE|AO_EXTI_MODE_FALLING|AO_EXTI_MODE_RISING|AO_EXTI_PRIORITY_MED, \
 129                               ao_quadrature_isr);                       \
 130                 ao_exti_enable(port(q), bitb(q));                       \
 131         } while (0)
 132
 133 void
 134 ao_quadrature_init(void)
 135 {
 136 #if AO_QUADRATURE_COUNT > 0
 137         init(0);
 138 #endif
 139 #if AO_QUADRATURE_COUNT > 1
 140         init(1);
 141 #endif
 142         ao_cmd_register(&ao_quadrature_cmds[0]);
 143 }