ESP8266 platform support

Author: pstolarz

README.md

@@ -42,6 +42,9 @@ devices (e.g. Dallas/Maxim thermometers).
 * Arduino megaAVR (recent Microchip AVR architecture).
     * Platform class: `OneWireNg_ArduinoMegaAVR`.
     * **Not tested**.
+* Arduino ESP8266.
+    * Platform class: `OneWireNg_ArduinoESP8266`.
+    * **Not tested**.
 
 NOTE: Expect more platforms support in the future. **I'm inviting all developers**,
 eager to help me with porting and testing the library for new platforms.

library.properties

@@ -6,4 +6,4 @@ sentence=Arduino 1-wire service library
 paragraph=An alternative for the classic Arduino OneWire library providing: (1) fixed handling of the 1-wire bus low-level activities related to its open-drain characteristic, (2) new I/O interface with enhanced parasite powering support, (3) improved overall software architecture.
 category=Communication
 url=https://github.com/pstolarz/OneWireNg
-architectures=avr,megaavr
+architectures=avr,megaavr,esp8266

src/OneWireNg.cpp

@@ -130,7 +130,7 @@ uint8_t OneWireNg::crc8(const void *in, size_t len)
 #elif (CONFIG_CRC8_TAB == CRC8_TAB_16LH)
     static const uint8_t CRCTAB_STORAGE CRC8_16L[] = {
         0x00, 0x5e, 0xbc, 0xe2, 0x61, 0x3f, 0xdd, 0x83,
-        0xc2, 0x9c, 0x7e, 0x20, 0xa3, 0xfd, 0x1f, 0x41,
+        0xc2, 0x9c, 0x7e, 0x20, 0xa3, 0xfd, 0x1f, 0x41
     };
     static const uint8_t CRCTAB_STORAGE CRC8_16H[] = {
         0x00, 0x9d, 0x23, 0xbe, 0x46, 0xdb, 0x65, 0xf8,

src/OneWireNg_ArduinoESP8266.h

@@ -0,0 +1,146 @@
+/*
+ * Copyright (c) 2019 Piotr Stolarz
+ * OneWireNg: Ardiono 1-wire service library
+ *
+ * Distributed under the 2-clause BSD License (the License)
+ * see accompanying file LICENSE for details.
+ *
+ * This software is distributed WITHOUT ANY WARRANTY; without even the
+ * implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+ * See the License for more information.
+ */
+
+#ifndef __OWNG_ARDUINO_ESP8266__
+#define __OWNG_ARDUINO_ESP8266__
+
+#include "Arduino.h"
+#include "OneWireNg_BitBang.h"
+
+#define __WRITE_GPIO(pin, st) \
+    if (pin < 16) { \
+        if (st) GPOS = (1 << pin); else GPOC = (1 << pin); \
+    } else \
+    if (pin == 16) { \
+        if (st) GP16O |= 1; else GP16O &= ~1; \
+    }
+
+#define __GPIO_AS_INPUT(pin) \
+    if (pin < 16) { \
+        GPEC = (1 << pin); \
+    } else \
+    if (pin == 16) { \
+      GP16E &= ~1; \
+    }
+
+#define __GPIO_AS_OUTPUT(pin) \
+    if (pin < 16) { \
+        GPES = (1 << pin); \
+    } else \
+    if (pin == 16) { \
+      GP16E |= 1; \
+    }
+
+/**
+ * Arduino ESP8266 platform GPIO specific implementation.
+ */
+class OneWireNg_ArduinoESP8266: public OneWireNg_BitBang
+{
+public:
+    /**
+     * OneWireNg 1-wire service for Arduino ESP8266 platform.
+     *
+     * Bus powering is supported via switching its GPIO to the high state.
+     * In this case the GPIO servers as a voltage source for connected slaves
+     * working in parasite powering configuration.
+     *
+     * @param pin Arduino GPIO pin number used for bit-banging 1-wire bus.
+     * @param pullUp If @c true configure internal pull-up resistor for the bus.
+     */
+    OneWireNg_ArduinoESP8266(unsigned pin, bool pullUp):
+        OneWireNg_BitBang(false)
+    {
+        _dtaPin = pin;
+        initDtaGpio(pullUp);
+    }
+
+    /**
+     * OneWireNg 1-wire service for Arduino ESP8266 platform.
+     *
+     * Bus powering is supported via a switching transistor providing
+     * the power to the bus and controlled by a dedicated GPIO (see @sa
+     * OneWireNg_BitBang::setupPwrCtrlGpio()). In this configuration the
+     * service mimics the open-drain type of output. The approach may be
+     * feasible if the GPIO is unable to provide sufficient power for
+     * connected slaves working in parasite powering configuration.
+     *
+     * @param pin Arduino GPIO pin number used for bit-banging 1-wire bus.
+     * @param pwrCtrlPin Arduino GPIO pin number controlling the switching
+     *     transistor.
+     * @param pullUp If @c true configure internal pull-up resistor for the bus.
+     */
+    OneWireNg_ArduinoESP8266(unsigned pin, unsigned pwrCtrlPin, bool pullUp):
+        OneWireNg_BitBang(true)
+    {
+        _dtaPin = pin;
+        _pwrCtrlPin = pwrCtrlPin;
+
+        initDtaGpio(pullUp);
+        initPwrCtrlGpio();
+    }
+
+protected:
+    virtual int readGpioIn(GpioType gpio)
+    {
+        UNUSED(gpio);
+        return (_dtaPin < 16 ? GPIP(_dtaPin) :
+            _dtaPin == 16 ? (GP16I & 0x01) : 1);
+    }
+
+    virtual void writeGpioOut(GpioType gpio, int state)
+    {
+        if (gpio == GPIO_DTA) {
+            __WRITE_GPIO(_dtaPin, state);
+        } else {
+            __WRITE_GPIO(_pwrCtrlPin, state);
+        }
+    }
+
+    virtual void setGpioAsInput(GpioType gpio)
+    {
+        UNUSED(gpio);
+        __GPIO_AS_INPUT(_dtaPin);
+    }
+
+    virtual void setGpioAsOutput(GpioType gpio, int state)
+    {
+        if (gpio == GPIO_DTA) {
+            __GPIO_AS_OUTPUT(_dtaPin);
+            __WRITE_GPIO(_dtaPin, state);
+        } else {
+            __GPIO_AS_OUTPUT(_pwrCtrlPin);
+            __WRITE_GPIO(_pwrCtrlPin, state);
+        }
+    }
+
+    void initDtaGpio(bool pullUp)
+    {
+        pinMode(_dtaPin, (pullUp ? INPUT_PULLUP : INPUT));
+        setupDtaGpio();
+    }
+
+    void initPwrCtrlGpio(void)
+    {
+        pinMode(_pwrCtrlPin, OUTPUT_OPEN_DRAIN);
+        setupPwrCtrlGpio(true);
+    }
+
+private:
+    unsigned _dtaPin;
+    unsigned _pwrCtrlPin;
+};
+
+#undef __GPIO_AS_OUTPUT
+#undef __GPIO_AS_INPUT
+#undef __WRITE_GPIO
+
+#endif /* __OWNG_ARDUINO_ESP8266__ */