Merge pull request #372 from panoti/feature/pcf8591

8-bit digital-to-analog conversion PCF8591 library

examples/pcf8591/Makefile

@@ -0,0 +1,3 @@
+PROGRAM = pcf8591
+EXTRA_COMPONENTS = extras/i2c extras/pcf8591
+include ../../common.mk

examples/pcf8591/main.c

@@ -0,0 +1,36 @@
+#include <stdio.h>
+
+#include "espressif/esp_common.h"
+#include "esp/uart.h"
+
+#include "FreeRTOS.h"
+#include "task.h"
+
+#include "i2c/i2c.h"
+#include "pcf8591/pcf8591.h"
+
+#define SCL_PIN 5
+#define SDA_PIN 4
+
+static void measure(void *pvParameters)
+{
+    while (1)
+    {
+        vTaskDelay(1000 / portTICK_PERIOD_MS);
+        printf("Value: %d\n", pcf8591_read(PCF8591_DEFAULT_ADDRESS, 0x03));
+    }
+}
+
+void user_init(void)
+{
+    uart_set_baud(0, 115200);
+
+    // Just some information
+    printf("\n");
+    printf("SDK version : %s\n", sdk_system_get_sdk_version());
+    printf("GIT version : %s\n", GITSHORTREV);
+
+    i2c_init(SCL_PIN, SDA_PIN);
+
+    xTaskCreate(measure, "measure_task", 256, NULL, 2, NULL);
+}

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 +1,22 @@
+#include <stddef.h>
+#include <stdint.h>
+
+#include <i2c/i2c.h>
+#include "pcf8591.h"
+
+/**
+ * CAUTION: PLEASE SET I2C_FREQUENCY_400K IS 'false' IN 'i2c.h' FILE
+ */
+
+#define PCF8591_CTRL_REG_READ 0x03
+
+uint8_t
+pcf8591_read(uint8_t addr, uint8_t analog_pin)
+{
+    uint8_t res = 0;
+    uint8_t control_reg = PCF8591_CTRL_REG_READ & analog_pin;
+
+    i2c_slave_read(addr, &control_reg, &res, 1);
+
+    return res;
+}

extras/pcf8591/pcf8591.h

@@ -0,0 +1,42 @@
+/**
+ * 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
+
+/**
+ * CAUTION: PLEASE SET I2C_FREQUENCY_400K IS 'false' IN 'i2c.h' FILE
+ */
+
+#define PCF8591_DEFAULT_ADDRESS 0x48
+
+void pcf8591_init(void);
+
+/**
+ * Read input value of an analog pin.
+ * @param[in] addr Pointer to device
+ * @param[in] analog_pin pin number:
+ *            0 - AIN0
+ *            1 - AIN1
+ *            2 - AIN2
+ *            3 - AIN3
+ * @return analog value
+ */
+uint8_t pcf8591_read(uint8_t addr, uint8_t analog_pin);
+
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* _EXTRAS_PCF8591_H_ */