add

extras/pcf8591/component.mk

@@ -0,0 +1,6 @@
+# Component makefile for extras/pcf8591
+
+INC_DIRS += $(pcf8591_ROOT)..
+pcf8591_SRC_DIR =  $(pcf8591_ROOT)
+
+$(eval $(call component_compile_rules,pcf8591))

extras/pcf8591/pcf8591.c

@@ -0,0 +1,15 @@
+#include <stddef.h>
+#include <stdint.h>
+#include <stdbool.h>
+
+#include <i2c/i2c.h>
+#include "pcf8591.h"
+
+static uint8_t mAddress = PCF8591_DEFAULT_ADDRESS;
+static float mVoltage = 3.3f;
+
+void
+pcf8591_set_address(uint8_t addr)
+{
+    //
+}

extras/pcf8591/pcf8591.h

@@ -0,0 +1,31 @@
+/**
+ * Driver for  8-bit analog-to-digital conversion and
+ * an 8-bit digital-to-analog conversion PCF8591
+ *
+ * Part of esp-open-rtos
+ * Copyright (C) 2017 Pham Ngoc Thanh <pnt239@gmail.com>
+ * BSD Licensed as described in the file LICENSE
+ */
+#ifndef _EXTRAS_PCF8591_H_
+#define _EXTRAS_PCF8591_H_
+
+#ifdef __cplusplus
+extern "C"
+{
+#endif
+
+#define PCF8591_DEFAULT_ADDRESS 0x90
+
+/**
+ * Set new sensor address for switching another.
+ * @param[in] addr Pointer to device
+ * @return none
+ */
+void pcf8591_set_address(uint8_t addr);
+
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* _EXTRAS_PCF8591_H_ */