bh1750 i2c light sensor driver + pwm cleanup (#330)

Add bh1750 (I2C light sensor) driver + usage example

examples/bh1750/Makefile

@@ -0,0 +1,3 @@
+PROGRAM=bh1750_example
+EXTRA_COMPONENTS = extras/i2c extras/bh1750
+include ../../common.mk

examples/bh1750/bh1750_example.c

@@ -0,0 +1,41 @@
+#include <stdio.h>
+
+#include "espressif/esp_common.h"
+#include "esp/uart.h"
+
+#include "FreeRTOS.h"
+#include "task.h"
+
+#include "i2c/i2c.h"
+#include "bh1750/bh1750.h"
+
+#define SCL_PIN 5
+#define SDA_PIN 4
+
+static void measure(void *pvParameters)
+{
+    bh1750_configure(BH1750_ADDR_LO,
+                     BH1750_CONTINUOUS_MODE | BH1750_HIGH_RES_MODE);
+
+    while (1) {
+        while(1) {
+            vTaskDelay(200 / portTICK_PERIOD_MS);
+            
+            printf("Lux: %d\n", bh1750_read(BH1750_ADDR_LO));
+        }
+    }
+}
+
+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/bh1750/bh1750.c

@@ -0,0 +1,28 @@
+/*
+ * Driver for BH1750 light sensor
+ *
+ * Part of esp-open-rtos
+ * Copyright (C) 2017 Andrej Krutak <dev@andree.sk>
+ * BSD Licensed as described in the file LICENSE
+ */
+#include "bh1750.h"
+#include <i2c/i2c.h>
+#include <stdio.h>
+
+void bh1750_configure(uint8_t addr, uint8_t mode)
+{
+	i2c_slave_write(addr, NULL, &mode, 1);
+}
+
+uint16_t bh1750_read(uint8_t addr)
+{
+	uint8_t buf[2];
+	uint16_t level;
+
+	i2c_slave_read(addr, NULL, buf, 2);
+
+	level = buf[0] << 8 | buf[1];
+	level = (level * 10) / 12; // convert to LUX
+
+	return level;
+}

extras/bh1750/bh1750.h

@@ -0,0 +1,82 @@
+/*
+ * Driver for BH1750 light sensor
+ *
+ * Part of esp-open-rtos
+ * Copyright (C) 2017 Andrej Krutak <dev@andree.sk>
+ * BSD Licensed as described in the file LICENSE
+ *
+ * ROHM Semiconductor bh1750fvi-e.pdf
+ */
+#ifndef EXTRAS_BH1750_H_
+#define EXTRAS_BH1750_H_
+
+#include <stdint.h>
+#include <stdbool.h>
+#include <time.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* Possible chip addresses */
+#define BH1750_ADDR_LO 0x23 // ADDR pin floating/low
+#define BH1750_ADDR_HI 0x5c
+
+
+/* Configuration options */
+
+// No active state
+#define BH1750_POWER_DOWN 0x00
+
+// Wating for measurement command
+#define BH1750_POWER_ON 0x01
+
+// Reset data register value - not accepted in POWER_DOWN mode
+#define BH1750_RESET 0x07
+
+
+/* Measurement modes */
+
+#define BH1750_CONTINUOUS_MODE  0x10
+#define BH1750_ONE_TIME_MODE  0x20
+
+// Start measurement at 1 lx resolution (measurement time typically 120ms)
+#define BH1750_HIGH_RES_MODE 0x00
+// Start measurement at 0.5 lx resolution  (measurement time typically 120ms)
+#define BH1750_HIGH_RES_MODE2 0x01
+// Start measurement at 4 lx resolution  (measurement time typically 16ms)
+#define BH1750_LOW_RES_MODE 0x03
+
+/* Adjust measurement time to account for optical window size (see datasheet).
+ * Procedure from datasheet suggests order Hi, Low and finally measurement mode
+ */
+#define BH1750_MEASURE_TIME_HI(mt) (0x40 | (((mt) >> 5) & 0x7))
+#define BH1750_MEASURE_TIME_LO(mt) (0x60 | ((mt) & 0x1f))
+#define BH1750_DEFAULT_MEASURE_TIME 0x45
+
+
+/**
+ * Configure the device.
+ * @param addr Device address
+ * @param mode Combination of BH1750_* flags
+ *
+ * May be called multiple times e.g. to configure the measurement time and
+ * the readout mode afterwards - or if one time mode is used consecutively.
+ *
+ * Example: BH1750_ADDR_LO, BH1750_CONTINUOUS_MODE | BH1750_HIGH_RES_MODE
+ */
+void bh1750_configure(uint8_t addr, uint8_t mode);
+
+/**
+ * Read LUX value from the device.
+ *
+ * @param addr Device address
+ * @returns read value in lux units
+ */
+uint16_t bh1750_read(uint8_t addr);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* EXTRAS_BH1750_H_ */

extras/bh1750/component.mk

@@ -0,0 +1,9 @@
+# Component makefile for extras/bh1750
+
+# expected anyone using RTC driver includes it as 'bh1750/bh1750.h'
+INC_DIRS += $(bh1750_ROOT)..
+
+# args for passing into compile rule generation
+bh1750_SRC_DIR =  $(bh1750_ROOT)
+
+$(eval $(call component_compile_rules,bh1750))

extras/pwm/pwm.c

@@ -29,7 +29,7 @@ typedef struct pwmInfoDefinition
     uint8_t running;
 
     uint16_t freq;
-    uint16_t dutyCicle;
+    uint16_t dutyCycle;
 
     /* private */
     uint32_t _maxLoad;
@@ -66,7 +66,7 @@ static void frc1_interrupt_handler(void)
     pwmInfo._step = step;
 }
 
-void pwm_init(uint8_t npins, uint8_t* pins)
+void pwm_init(uint8_t npins, const uint8_t* pins)
 {
     /* Assert number of pins is correct */
     if (npins > MAX_PWM_PINS)
@@ -127,10 +127,10 @@ void pwm_set_duty(uint16_t duty)
 {
     bool output;
 
-    pwmInfo.dutyCicle = duty;
+    pwmInfo.dutyCycle = duty;
     if (duty > 0 && duty < UINT16_MAX) {
         pwm_restart();
-	return;
+        return;
     }
 
     // 0% and 100% duty cycle are special cases: constant output.
@@ -139,7 +139,7 @@ void pwm_set_duty(uint16_t duty)
     output = (duty == UINT16_MAX);
     for (uint8_t i = 0; i < pwmInfo.usedPins; ++i)
     {
-	gpio_write(pwmInfo.pins[i].pin, output);
+        gpio_write(pwmInfo.pins[i].pin, output);
     }
 }
 
@@ -154,7 +154,7 @@ void pwm_restart()
 
 void pwm_start()
 {
-    pwmInfo._onLoad = pwmInfo.dutyCicle * pwmInfo._maxLoad / UINT16_MAX;
+    pwmInfo._onLoad = pwmInfo.dutyCycle * pwmInfo._maxLoad / UINT16_MAX;
     pwmInfo._offLoad = pwmInfo._maxLoad - pwmInfo._onLoad;
     pwmInfo._step = PERIOD_ON;
 

extras/pwm/pwm.h

@@ -16,7 +16,7 @@
 extern "C" {
 #endif
 
-void pwm_init(uint8_t npins, uint8_t* pins);
+void pwm_init(uint8_t npins, const uint8_t* pins);
 void pwm_set_freq(uint16_t freq);
 void pwm_set_duty(uint16_t duty);