2 * Copyright © 2012 Keith Packard <keithp@keithp.com>
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.
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.
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.
19 #include <ao_quadrature.h>
21 #include <ao_fast_timer.h>
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];
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)))
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
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);
42 return ~((((v >> pin_a) & 1) | (((v >> pin_b) & 1) << 1))) & 3;
45 #define _ao_quadrature_get(q) ao_quadrature_read(port(q), bita(q), bitb(q))
48 _ao_quadrature_queue(uint8_t q, int8_t step)
50 ao_quadrature_count[q] += step;
52 ao_event_put_isr(AO_EVENT_QUADRATURE, q, step);
54 ao_wakeup(&ao_quadrature_count[q]);
57 static const int8_t step[16] = {
59 [STATE(0,0,0,1)] = -1,
64 [STATE(0,1,1,1)] = -1,
65 [STATE(1,0,0,0)] = -1,
71 [STATE(1,1,1,0)] = -1,
76 _ao_quadrature_set(uint8_t q, uint8_t value) {
79 v = ao_quadrature_state[q] & 3;
85 ao_quadrature_state[q] = (v << 2) | value;
87 ao_quadrature_raw[q] += step[ao_quadrature_state[q]];
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;
98 ao_quadrature_isr(void)
100 _ao_quadrature_set(0, _ao_quadrature_get(0));
101 _ao_quadrature_set(1, _ao_quadrature_get(1));
105 ao_quadrature_poll(uint8_t q)
108 ao_arch_critical(ret = ao_quadrature_count[q];);
113 ao_quadrature_wait(uint8_t q)
115 ao_sleep(&ao_quadrature_count[q]);
116 return ao_quadrature_poll(q);
120 ao_quadrature_test(void)
126 if (q >= AO_QUADRATURE_COUNT) {
127 ao_cmd_status = ao_cmd_syntax_error;
130 printf ("count %d state %x raw %d\n",
131 ao_quadrature_count[q],
132 ao_quadrature_state[q],
133 ao_quadrature_raw[q]);
138 c = ao_quadrature_wait(q);
139 printf ("new count %6d\n", c);
146 static const struct ao_cmds ao_quadrature_cmds[] = {
147 { ao_quadrature_test, "q <unit>\0Test quadrature" },
151 #define init(q) do { \
152 ao_enable_input(port(q), bita(q), 0); \
153 ao_enable_input(port(q), bitb(q), 0); \
157 ao_quadrature_init(void)
159 #if AO_QUADRATURE_COUNT > 0
162 #if AO_QUADRATURE_COUNT > 1
165 ao_fast_timer_init();
166 ao_fast_timer_on(ao_quadrature_isr);
167 ao_cmd_register(&ao_quadrature_cmds[0]);