From be10ccdb6bcf244e4a06758464d5867c6b563eac Mon Sep 17 00:00:00 2001
From: Jason Schmidlapp <Jason.Schmidlapp@gmail.com>
Date: Sun, 5 Jun 2016 13:59:55 -0700
Subject: [PATCH] Added support for Analog Devices ADXL345 accelerometer
 (#1252)

---
 app/include/user_modules.h |  2 +-
 app/modules/adxl345.c      | 95 ++++++++++++++++++++++++++++++++++++++
 docs/en/modules/adxl345.md | 36 +++++++++++++++
 mkdocs.yml                 |  1 +
 4 files changed, 133 insertions(+), 1 deletion(-)
 create mode 100644 app/modules/adxl345.c
 create mode 100644 docs/en/modules/adxl345.md

diff --git a/app/include/user_modules.h b/app/include/user_modules.h
index 0b046db6..af393be2 100644
--- a/app/include/user_modules.h
+++ b/app/include/user_modules.h
@@ -18,6 +18,7 @@
 // See https://github.com/nodemcu/nodemcu-firmware/pull/1127 for discussions.
 // New modules should be disabled by default and added in alphabetical order.
 #define LUA_USE_MODULES_ADC
+//#define LUA_USE_MODULES_ADXL345
 //#define LUA_USE_MODULES_AM2320
 //#define LUA_USE_MODULES_APA102
 #define LUA_USE_MODULES_BIT
@@ -61,6 +62,5 @@
 //#define LUA_USE_MODULES_WS2801
 //#define LUA_USE_MODULES_WS2812
 
-
 #endif  /* LUA_CROSS_COMPILER */
 #endif	/* __USER_MODULES_H__ */
diff --git a/app/modules/adxl345.c b/app/modules/adxl345.c
new file mode 100644
index 00000000..f248bf77
--- /dev/null
+++ b/app/modules/adxl345.c
@@ -0,0 +1,95 @@
+/*
+ * Driver for Analog Devices ADXL345 accelerometer.
+ *
+ * Code based on BMP085 driver.
+ */
+#include "module.h"
+#include "lauxlib.h"
+#include "platform.h"
+#include "c_stdlib.h"
+#include "c_string.h"
+
+static const uint32_t adxl345_i2c_id = 0;
+static const uint8_t adxl345_i2c_addr = 0x53;
+
+static uint8_t ICACHE_FLASH_ATTR r8u(uint32_t id, uint8_t reg) {
+    uint8_t ret;
+
+    platform_i2c_send_start(id);
+    platform_i2c_send_address(id, adxl345_i2c_addr, PLATFORM_I2C_DIRECTION_TRANSMITTER);
+    platform_i2c_send_byte(id, reg);
+    platform_i2c_send_stop(id);
+    platform_i2c_send_start(id);
+    platform_i2c_send_address(id, adxl345_i2c_addr, PLATFORM_I2C_DIRECTION_RECEIVER);
+    ret = platform_i2c_recv_byte(id, 0);
+    platform_i2c_send_stop(id);
+    return ret;
+}
+
+static int ICACHE_FLASH_ATTR adxl345_init(lua_State* L) {
+
+    uint32_t sda;
+    uint32_t scl;
+    uint8_t  devid;
+
+    sda = luaL_checkinteger(L, 1);
+    scl = luaL_checkinteger(L, 2);
+
+    luaL_argcheck(L, sda > 0 && scl > 0, 1, "no i2c for D0");
+
+    platform_i2c_setup(adxl345_i2c_id, sda, scl, PLATFORM_I2C_SPEED_SLOW);
+    
+    devid = r8u(adxl345_i2c_id, 0x00);
+
+    if (devid != 229) {
+        return luaL_error(L, "device not found");
+    }
+
+    // Enable sensor
+    platform_i2c_send_start(adxl345_i2c_id);
+    platform_i2c_send_address(adxl345_i2c_id, adxl345_i2c_addr, PLATFORM_I2C_DIRECTION_TRANSMITTER);
+    platform_i2c_send_byte(adxl345_i2c_id, 0x2D);
+    platform_i2c_send_byte(adxl345_i2c_id, 0x08);
+    platform_i2c_send_stop(adxl345_i2c_id);
+
+    return 0;
+}
+
+static int ICACHE_FLASH_ATTR adxl345_read(lua_State* L) {
+
+    uint8_t data[6];
+    int x,y,z;
+    int i;
+
+    platform_i2c_send_start(adxl345_i2c_id);
+    platform_i2c_send_address(adxl345_i2c_id, adxl345_i2c_addr, PLATFORM_I2C_DIRECTION_TRANSMITTER);
+    platform_i2c_send_byte(adxl345_i2c_id, 0x32);
+    platform_i2c_send_start(adxl345_i2c_id);
+    platform_i2c_send_address(adxl345_i2c_id, adxl345_i2c_addr, PLATFORM_I2C_DIRECTION_RECEIVER);
+
+    for (i=0; i<5; i++) {
+	data[i] = platform_i2c_recv_byte(adxl345_i2c_id, 1);
+    }
+    
+    data[5] = platform_i2c_recv_byte(adxl345_i2c_id, 0);
+
+    platform_i2c_send_stop(adxl345_i2c_id);
+
+    x = (int16_t) ((data[1] << 8) | data[0]);
+    y = (int16_t) ((data[3] << 8) | data[2]);
+    z = (int16_t) ((data[5] << 8) | data[4]);
+
+    lua_pushinteger(L, x);
+    lua_pushinteger(L, y);
+    lua_pushinteger(L, z);
+
+    return 3;
+}
+
+static const LUA_REG_TYPE adxl345_map[] = {
+    { LSTRKEY( "read" ),         LFUNCVAL( adxl345_read )},
+    { LSTRKEY( "init" ),         LFUNCVAL( adxl345_init )},
+    { LNILKEY, LNILVAL}
+};
+
+NODEMCU_MODULE(ADXL345, "adxl345", adxl345_map, NULL);
diff --git a/docs/en/modules/adxl345.md b/docs/en/modules/adxl345.md
new file mode 100644
index 00000000..150e0524
--- /dev/null
+++ b/docs/en/modules/adxl345.md
@@ -0,0 +1,36 @@
+# ADXL345 Module
+| Since  | Origin / Contributor  | Maintainer  | Source  |
+| :----- | :-------------------- | :---------- | :------ |
+| 2016-04-08 | [Jason Schmidlapp](https://github.com/jschmidlapp) | [Jason Schmidlapp](https://github.com/jschmidlapp) | [adxl345.c](../../../app/modules/adxl345.c)|
+
+
+This module provides access to the [ADXL345](https://www.sparkfun.com/products/9836) triple axis accelerometer.
+
+## adxl345.read()
+Samples the sensor and returns X,Y and Z data from the accelerometer.
+
+#### Syntax
+`adxl345.read()`
+
+#### Returns
+X,Y,Z data (integers)
+
+#### Example
+```lua
+adxl345.init(1, 2)
+local x,y,z = adxl345.read()
+print(string.format("X = %d, Y = %d, Z = %d", x, y, z))
+```
+
+## adxl345.init()
+Initializes the module and sets the pin configuration.
+
+#### Syntax
+`adxl345.init(sda, scl)`
+
+#### Parameters
+- `sda` data pin
+- `scl` clock pin
+
+#### Returns
+`nil`
diff --git a/mkdocs.yml b/mkdocs.yml
index 350081b6..45fee75c 100644
--- a/mkdocs.yml
+++ b/mkdocs.yml
@@ -34,6 +34,7 @@ pages:
     - Support: 'en/support.md'
     - Modules:
         - 'adc': 'en/modules/adc.md'
+        - 'adxl345': 'en/modules/adxl345.md'
         - 'am2320': 'en/modules/am2320.md'
         - 'apa102': 'en/modules/apa102.md'
         - 'bit': 'en/modules/bit.md'