esp8266: Add onewire helper functions as C module.

Includes functions to read and write bits and bytes.

esp8266/Makefile

@@ -67,6 +67,7 @@ SRC_C = \
 	modutime.c \
 	moduos.c \
 	modmachine.c \
+	modonewire.c \
 	utils.c \
 	ets_alt_task.c \
 	$(BUILD)/frozen.c \

esp8266/modonewire.c

+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2015 Damien P. George
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include <stdio.h>
+#include <stdint.h>
+
+#include "etshal.h"
+#include "user_interface.h"
+#include "py/obj.h"
+#include "py/mphal.h"
+#include "modpyb.h"
+
+STATIC uint32_t disable_irq(void) {
+    ets_intr_lock();
+    return 0;
+}
+
+STATIC void enable_irq(uint32_t i) {
+    ets_intr_unlock();
+}
+
+STATIC void mp_hal_delay_us_no_irq(uint32_t us) {
+    uint32_t start = system_get_time();
+    while (system_get_time() - start < us) {
+    }
+}
+
+#define DELAY_US mp_hal_delay_us_no_irq
+
+#define TIMING_RESET1 (0)
+#define TIMING_RESET2 (1)
+#define TIMING_RESET3 (2)
+#define TIMING_READ1 (3)
+#define TIMING_READ2 (4)
+#define TIMING_READ3 (5)
+#define TIMING_WRITE1 (6)
+#define TIMING_WRITE2 (7)
+#define TIMING_WRITE3 (8)
+
+static int timings[] = {480, 40, 420, 5, 5, 40, 10, 50, 10};
+
+STATIC mp_obj_t onewire_timings(mp_obj_t timings_in) {
+    mp_obj_t *items;
+    mp_obj_get_array_fixed_n(timings_in, 9, &items);
+    for (int i = 0; i < 9; ++i) {
+        timings[i] = mp_obj_get_int(items[i]);
+    }
+    return mp_const_none;
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_1(onewire_timings_obj, onewire_timings);
+
+STATIC mp_obj_t onewire_reset(mp_obj_t pin_in) {
+    uint pin = mp_obj_get_pin(pin_in);
+    pin_set(pin, 0);
+    DELAY_US(timings[TIMING_RESET1]);
+    uint32_t i = disable_irq();
+    pin_set(pin, 1);
+    DELAY_US(timings[TIMING_RESET2]);
+    int status = !pin_get(pin);
+    enable_irq(i);
+    DELAY_US(timings[TIMING_RESET3]);
+    return mp_obj_new_bool(status);
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_1(onewire_reset_obj, onewire_reset);
+
+STATIC int _onewire_readbit(uint pin) {
+    pin_set(pin, 1);
+    uint32_t i = disable_irq();
+    pin_set(pin, 0);
+    DELAY_US(timings[TIMING_READ1]);
+    pin_set(pin, 1);
+    DELAY_US(timings[TIMING_READ2]);
+    int value = pin_get(pin);
+    enable_irq(i);
+    DELAY_US(timings[TIMING_READ3]);
+    return value;
+}
+
+STATIC mp_obj_t onewire_readbit(mp_obj_t pin_in) {
+    return MP_OBJ_NEW_SMALL_INT(_onewire_readbit(mp_obj_get_pin(pin_in)));
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_1(onewire_readbit_obj, onewire_readbit);
+
+STATIC mp_obj_t onewire_readbyte(mp_obj_t pin_in) {
+    uint pin = mp_obj_get_pin(pin_in);
+    uint8_t value = 0;
+    for (int i = 0; i < 8; ++i) {
+        value |= _onewire_readbit(pin) << i;
+    }
+    return MP_OBJ_NEW_SMALL_INT(value);
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_1(onewire_readbyte_obj, onewire_readbyte);
+
+STATIC void _onewire_writebit(uint pin, int value) {
+    uint32_t i = disable_irq();
+    pin_set(pin, 0);
+    DELAY_US(timings[TIMING_WRITE1]);
+    pin_set(pin, value);
+    DELAY_US(timings[TIMING_WRITE2]);
+    pin_set(pin, 1);
+    DELAY_US(timings[TIMING_WRITE3]);
+    enable_irq(i);
+}
+
+STATIC mp_obj_t onewire_writebit(mp_obj_t pin_in, mp_obj_t value_in) {
+    _onewire_writebit(mp_obj_get_pin(pin_in), mp_obj_get_int(value_in));
+    return mp_const_none;
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_2(onewire_writebit_obj, onewire_writebit);
+
+STATIC mp_obj_t onewire_writebyte(mp_obj_t pin_in, mp_obj_t value_in) {
+    uint pin = mp_obj_get_pin(pin_in);
+    int value = mp_obj_get_int(value_in);
+    for (int i = 0; i < 8; ++i) {
+        _onewire_writebit(pin, value & 1);
+        value >>= 1;
+    }
+    return mp_const_none;
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_2(onewire_writebyte_obj, onewire_writebyte);
+
+STATIC mp_obj_t onewire_crc8(mp_obj_t data) {
+    mp_buffer_info_t bufinfo;
+    mp_get_buffer_raise(data, &bufinfo, MP_BUFFER_READ);
+    uint8_t crc = 0;
+    for (size_t i = 0; i < bufinfo.len; ++i) {
+        uint8_t byte = ((uint8_t*)bufinfo.buf)[i];
+        for (int b = 0; b < 8; ++b) {
+            uint8_t fb_bit = (crc ^ byte) & 0x01;
+            if (fb_bit == 0x01) {
+                crc = crc ^ 0x18;
+            }
+            crc = (crc >> 1) & 0x7f;
+            if (fb_bit == 0x01) {
+                crc = crc | 0x80;
+            }
+            byte = byte >> 1;
+        }
+    }
+    return MP_OBJ_NEW_SMALL_INT(crc);
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_1(onewire_crc8_obj, onewire_crc8);
+
+STATIC const mp_map_elem_t onewire_module_globals_table[] = {
+    { MP_ROM_QSTR(MP_QSTR___name__), MP_ROM_QSTR(MP_QSTR_onewire) },
+
+    { MP_ROM_QSTR(MP_QSTR_timings), MP_ROM_PTR((mp_obj_t)&onewire_timings_obj) },
+    { MP_ROM_QSTR(MP_QSTR_reset), MP_ROM_PTR((mp_obj_t)&onewire_reset_obj) },
+    { MP_ROM_QSTR(MP_QSTR_readbit), MP_ROM_PTR((mp_obj_t)&onewire_readbit_obj) },
+    { MP_ROM_QSTR(MP_QSTR_readbyte), MP_ROM_PTR((mp_obj_t)&onewire_readbyte_obj) },
+    { MP_ROM_QSTR(MP_QSTR_writebit), MP_ROM_PTR((mp_obj_t)&onewire_writebit_obj) },
+    { MP_ROM_QSTR(MP_QSTR_writebyte), MP_ROM_PTR((mp_obj_t)&onewire_writebyte_obj) },
+    { MP_ROM_QSTR(MP_QSTR_crc8), MP_ROM_PTR((mp_obj_t)&onewire_crc8_obj) },
+};
+
+STATIC MP_DEFINE_CONST_DICT(onewire_module_globals, onewire_module_globals_table);
+
+const mp_obj_module_t onewire_module = {
+    .base = { &mp_type_module },
+    .name = MP_QSTR_onewire,
+    .globals = (mp_obj_dict_t*)&onewire_module_globals,
+};

esp8266/mpconfigport.h

@@ -94,6 +94,7 @@ extern const struct _mp_obj_module_t utime_module;
 extern const struct _mp_obj_module_t uos_module;
 extern const struct _mp_obj_module_t mp_module_lwip;
 extern const struct _mp_obj_module_t mp_module_machine;
+extern const struct _mp_obj_module_t onewire_module;
 
 #define MICROPY_PORT_BUILTIN_MODULES \
     { MP_OBJ_NEW_QSTR(MP_QSTR_pyb), (mp_obj_t)&pyb_module }, \
@@ -105,6 +106,7 @@ extern const struct _mp_obj_module_t mp_module_machine;
     { MP_OBJ_NEW_QSTR(MP_QSTR_utime), (mp_obj_t)&utime_module }, \
     { MP_OBJ_NEW_QSTR(MP_QSTR_uos), (mp_obj_t)&uos_module }, \
     { MP_OBJ_NEW_QSTR(MP_QSTR_machine), (mp_obj_t)&mp_module_machine }, \
+    { MP_OBJ_NEW_QSTR(MP_QSTR__onewire), (mp_obj_t)&onewire_module }, \
 
 #define MICROPY_PORT_BUILTIN_MODULE_WEAK_LINKS \
     { MP_OBJ_NEW_QSTR(MP_QSTR_time), (mp_obj_t)&utime_module }, \

esp8266/qstrdefsport.h

@@ -178,4 +178,15 @@ Q(period)
 Q(ONE_SHOT)
 Q(PERIODIC)
 
+// onewire
+Q(_onewire)
+Q(onewire)
+Q(timings)
+Q(reset)
+Q(readbit)
+Q(readbyte)
+Q(writebit)
+Q(writebyte)
+Q(crc8)
+
 Q(json)