esp8266: Separate 1-wire timing funcs from Python module to save iRAM.

esponewire.c contains low-level timing-critical functions that go in
iRAM.  modonewire.c contains Python wrapper code.

esp8266/Makefile

@@ -60,6 +60,7 @@ SRC_C = \
 	lexerstr32.c \
 	uart.c \
 	esppwm.c \
+	esponewire.c \
 	espneopixel.c \
 	intr.c \
 	modpyb.c \

esp8266/esp8266.ld

@@ -146,6 +146,7 @@ SECTIONS
         *modutime.o(.literal* .text*)
         *modlwip.o(.literal* .text*)
         *modsocket.o(.literal* .text*)
+        *modonewire.o(.literal* .text*)
 
         /* we put as much rodata as possible in this section */
         /* note that only rodata accessed as a machine word is allowed here */

esp8266/esponewire.c

@@ -0,0 +1,99 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2015-2016 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 <stdint.h>
+
+#include "etshal.h"
+#include "user_interface.h"
+#include "modpyb.h"
+#include "esponewire.h"
+
+#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)
+
+uint16_t esp_onewire_timings[9] = {480, 40, 420, 5, 5, 40, 10, 50, 10};
+
+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
+
+int esp_onewire_reset(uint pin) {
+    pin_set(pin, 0);
+    DELAY_US(esp_onewire_timings[TIMING_RESET1]);
+    uint32_t i = disable_irq();
+    pin_set(pin, 1);
+    DELAY_US(esp_onewire_timings[TIMING_RESET2]);
+    int status = !pin_get(pin);
+    enable_irq(i);
+    DELAY_US(esp_onewire_timings[TIMING_RESET3]);
+    return status;
+}
+
+int esp_onewire_readbit(uint pin) {
+    pin_set(pin, 1);
+    uint32_t i = disable_irq();
+    pin_set(pin, 0);
+    DELAY_US(esp_onewire_timings[TIMING_READ1]);
+    pin_set(pin, 1);
+    DELAY_US(esp_onewire_timings[TIMING_READ2]);
+    int value = pin_get(pin);
+    enable_irq(i);
+    DELAY_US(esp_onewire_timings[TIMING_READ3]);
+    return value;
+}
+
+void esp_onewire_writebit(uint pin, int value) {
+    uint32_t i = disable_irq();
+    pin_set(pin, 0);
+    DELAY_US(esp_onewire_timings[TIMING_WRITE1]);
+    if (value) {
+        pin_set(pin, 1);
+    }
+    DELAY_US(esp_onewire_timings[TIMING_WRITE2]);
+    pin_set(pin, 1);
+    DELAY_US(esp_onewire_timings[TIMING_WRITE3]);
+    enable_irq(i);
+}

esp8266/esponewire.h

@@ -0,0 +1,36 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2016 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.
+ */
+
+#ifndef __MICROPY_INCLUDED_ESP8266_ESPONEWIRE_H__
+#define __MICROPY_INCLUDED_ESP8266_ESPONEWIRE_H__
+
+extern uint16_t esp_onewire_timings[9];
+
+int esp_onewire_reset(uint pin);
+int esp_onewire_readbit(uint pin);
+void esp_onewire_writebit(uint pin, int value);
+
+#endif // __MICROPY_INCLUDED_ESP8266_ESPONEWIRE_H__

esp8266/modonewire.c

@@ -27,80 +27,28 @@
 #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};
+#include "esponewire.h"
 
 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]);
+        esp_onewire_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);
+    return mp_obj_new_bool(esp_onewire_reset(mp_obj_get_pin(pin_in)));
 }
 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)));
+    return MP_OBJ_NEW_SMALL_INT(esp_onewire_readbit(mp_obj_get_pin(pin_in)));
 }
 STATIC MP_DEFINE_CONST_FUN_OBJ_1(onewire_readbit_obj, onewire_readbit);
 
@@ -108,25 +56,14 @@ 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;
+        value |= esp_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));
+    esp_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);
@@ -135,7 +72,7 @@ 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);
+        esp_onewire_writebit(pin, value & 1);
         value >>= 1;
     }
     return mp_const_none;