From dbcb707c1c3d4d25293a4121f648ba76b30e048b Mon Sep 17 00:00:00 2001
From: thanhpn <pano.tjoan@yahoo.com>
Date: Tue, 25 Apr 2017 23:57:40 +0700
Subject: [PATCH] add pcf8591 lib + example

---
 examples/pcf8591/main.c  | 51 +++++++++++++++++-----------------------
 extras/pcf8591/pcf8591.c | 19 ++++++++++-----
 extras/pcf8591/pcf8591.h | 19 +++++++++++----
 3 files changed, 50 insertions(+), 39 deletions(-)

diff --git a/examples/pcf8591/main.c b/examples/pcf8591/main.c
index 4b1e7a6..7547c75 100644
--- a/examples/pcf8591/main.c
+++ b/examples/pcf8591/main.c
@@ -1,43 +1,36 @@
-/*
- * Example of using PCA9685 PWM driver
- *
- * Part of esp-open-rtos
- * Copyright (C) 2016 Ruslan V. Uss <unclerus@gmail.com>
- * Public domain
- */
-#include <esp/uart.h>
-#include <espressif/esp_common.h>
-#include <i2c/i2c.h>
-#include <pca9685/pca9685.h>
 #include <stdio.h>
 
-#define ADDR 0x40
+#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
 
-#define PWM_FREQ 500
+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);
-    printf("SDK version:%s\n", sdk_system_get_sdk_version());
+
+    // 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);
 
-    pca9685_init(ADDR);
-
-    pca9685_set_pwm_frequency(ADDR, 1000);
-    printf("Freq 1000Hz, real %d\n", pca9685_get_pwm_frequency(ADDR));
-
-    uint16_t val = 0;
-    while (true)
-    {
-        printf("Set ch0 to %d, ch4 to %d\n", val, 4096 - val);
-        pca9685_set_pwm_value(ADDR, 0, val);
-        pca9685_set_pwm_value(ADDR, 4, 4096 - val);
-
-        if (val++ == 4096)
-            val = 0;
-    }
+    xTaskCreate(measure, "measure_task", 256, NULL, 2, NULL);
 }
diff --git a/extras/pcf8591/pcf8591.c b/extras/pcf8591/pcf8591.c
index c9b45f7..42b9df4 100644
--- a/extras/pcf8591/pcf8591.c
+++ b/extras/pcf8591/pcf8591.c
@@ -1,15 +1,22 @@
 #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;
+/**
+ * CAUTION: PLEASE SET I2C_FREQUENCY_400K IS 'false' IN 'i2c.h' FILE
+ */
 
-void
-pcf8591_set_address(uint8_t addr)
+#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;
 }
diff --git a/extras/pcf8591/pcf8591.h b/extras/pcf8591/pcf8591.h
index 2cfbfde..3deac57 100644
--- a/extras/pcf8591/pcf8591.h
+++ b/extras/pcf8591/pcf8591.h
@@ -14,14 +14,25 @@ extern "C"
 {
 #endif
 
-#define PCF8591_DEFAULT_ADDRESS 0x90
+/**
+ * CAUTION: PLEASE SET I2C_FREQUENCY_400K IS 'false' IN 'i2c.h' FILE
+ */
+
+#define PCF8591_DEFAULT_ADDRESS 0x48
+
+void pcf8591_init(void);
 
 /**
- * Set new sensor address for switching another.
+ * Read input value of an analog pin.
  * @param[in] addr Pointer to device
- * @return none
+ * @param[in] analog_pin pin number:
+ *            0 - AIN0
+ *            1 - AIN1
+ *            2 - AIN2
+ *            3 - AIN3
+ * @return analog value
  */
-void pcf8591_set_address(uint8_t addr);
+uint8_t pcf8591_read(uint8_t addr, uint8_t analog_pin);
 
 
 #ifdef __cplusplus