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第四章、为eLua添加自定义模块

  第四章内容迟迟没有迎来更新，小伙伴们估计都等不及了。距离上次elua文档正式发布也过了将近半个月的时间。当时在文末只留下了几个大字：未完待续。。。。你说看着正上瘾，刚准备动手实操下，突然就没了。

  我要是说结束了吧，各位也许还不会那么期待，可能只会觉得不够完美。这时候我偏偏来个未完待续，并且还写了第四章的标题为eLua添加自定义模块，这让人一看就知道后面还有干货，并且还是各位所期待的实操环节。

  正好前几天在csdk上发布了一个OneWire驱动库，这个库足够简单，就几个函数。今天正好就可以拿来练练手。

  进入正文之前我们先回顾下前三章讲了什么内容。前三章主要是讲了lua内核结构以及一些功能模块。并且举了两个现有的模块添加的例子，分别是adc和json，这些功能在现在的luat版本中都是已经存在的了，举例只是为了说明它们之间是什么样的关系。当时并没有讲编译的事情，对编译不熟悉的同学们，如果去自己尝试添加elua模块了，只看第三章的内容还真不一定能搞定。

  那么正好今天有点时间，我们就一起来看一下怎么自己注册一个自定义模块到elua中。

4.1、添加OneWire库到elua模块中

4.1.1、开始前准备

  正式开始前需要把OneWire软件包复制到elua下面的lib模块中。

  这时候有人会问了，既然OneWire是硬件模块，那就要和硬件打交道。为什么要放到lib目录下，第三章不是说了吗lib目录存放的是纯软驱动，不依赖外界环境吗。

  虽然OneWire是需要驱动硬件的，理论上讲就需要抽象层和外界硬件驱动库对接。但是又由于库函数不能满足使用的需求，代码中使用的是直接操作寄存器的方式控制的gpio，直接操作的内存地址。那就又不依赖外界代码库了了，看起来就像是一个纯软代码，那就又没必要抽象了。

  将elua/lib/OneWire目录下cmake文件修改成下面的代码：

set(target lua_OneWire)
add_library(${target} STATIC)
set_target_properties(${target} PROPERTIES ARCHIVE_OUTPUT_DIRECTORY ${out_lib_dir})target_include_directories(${target} PUBLIC ./)
target_include_directories(${target} PUBLIC dht11)
target_include_directories(${target} PUBLIC ./ds18b20)
target_include_directories(${target} PRIVATE  ${PROJECT_SOURCE_DIR}/components/openat_inc)target_sources(${target} PUBLIC./OneWire.cdht11/dht11.cds18b20/ds18b20.c
)

  将elua/lib目录下cmake文件修改成下面的代码：

add_subdirectory_if_exist(crypto)
add_subdirectory_if_exist(iconv)
add_subdirectory_if_exist(json)
add_subdirectory_if_exist(lzma)
add_subdirectory_if_exist(pbc)
add_subdirectory_if_exist(zlib)
add_subdirectory_if_exist(lpng)
add_subdirectory_if_exist(qr_encode)
add_subdirectory_if_exist(OneWire)#就添加了这么一行

4.1.2、注册函数

  打开elua/modules/include/auxmods.h，在文件中找个位置添加这么一段，增加声明OneWire模块的模块名和注册函数。

#define AUXLIB_OneWire    "OneWire"
LUALIB_API int ( luaopen_OneWire )( lua_State * L );

  别乱加哈。我建议和我一样，加在这个地方。

  打开elua/platform/openat/include/platform_conf.h，在文件中添加这么一段，完成将模块名和初始化函数注册到lua内核中。

    _ROM( AUXLIB_OneWire, luaopen_OneWire, OneWire_map) 

  这个就不能随便加了，大概加在这个地方。注意了要在上一条语句的结尾加上\

4.1.3、编写实现函数

  4.1.2完成后，那就需要实现一下lua代码与c对接的部分了。在elua/modules/src目录下新建luaOneWire.c文件。

  编写OneWire注册函数。注册了OneWire基础函数：微秒延时函数、切换输入输出函数、读取和设置函数。还有应用层函数读取ds18b20函数以及读取dht11函数。

#include "lrodefs.h"
const LUA_REG_TYPE OneWire_map[] = {{LSTRKEY("Delay1us"), LFUNCVAL(Delay1us)},{LSTRKEY("IOIN"), LFUNCVAL(IOIN)},{LSTRKEY("IOOUT"), LFUNCVAL(IOOUT)},{LSTRKEY("DQIN"), LFUNCVAL(DQIN)},{LSTRKEY("DQOUT"), LFUNCVAL(DQOUT)},{LSTRKEY("GetDS18B20Data"), LFUNCVAL(GetDS18B20Data)},{LSTRKEY("GetDHT11Data"), LFUNCVAL(GetDHT11Data)},{LNILKEY, LNILVAL}};LUALIB_API int luaopen_OneWire(lua_State *L)
{luaL_register(L, AUXLIB_OneWire, OneWire_map);return 1;
}

  基础函数的部分实现（除了微秒延时），这个直接调用C库就可以，啥都不用管。就只有四个函数，编写的流程就是读取传入参数--->调用c库运算--->返回运算结果。

static int IOIN(lua_State *L)
{uint8 pin = luaL_checkinteger(L, 1);lua_pushinteger(L, OneWire_IO_IN(pin));return 1;
}static int IOOUT(lua_State *L)
{uint8 pin = luaL_checkinteger(L, 1);OneWire_IO_OUT(pin);lua_pushinteger(L, 1);return 1;
}static int DQOUT(lua_State *L)
{uint8 pin = luaL_checkinteger(L, 1);uint8 level = luaL_checkinteger(L, 2);OneWire_DQ_OUT(pin, level);lua_pushinteger(L, 1);return 1;
}static int DQIN(lua_State *L)
{uint8 pin = luaL_checkinteger(L, 1);lua_pushinteger(L, OneWire_DQ_IN(pin));return 1;
}

  基础函数的微秒延时函数，不能直接使用OneWire库中现有的c库代码。现有的c库代码，延时是很精准的，但是lua调用时会存在一个翻译的过程，我大概测试了下，翻译一条语句到执行c函数大约需要4us的时间。所以需要在现有的c库基础上另外重新实现做减法运算，减掉翻译的时间。lua调用的时候由于单语句翻译就需要4us，这就导致5us以下的延时不可能实现。开放给上层使用只能使用5us以上的延时。

#pragma GCC push_options
#pragma GCC optimize("O0")
static int Delay1us(lua_State *L)
{uint32 num = luaL_checkinteger(L, 1);if (num >= 5 && num < 20){for (volatile int i = 60 * num - 70 * 4; i > 0; i--);}else if (num >= 20 && num < 100){for (volatile int i = 60 * num - 90 * 4; i > 0; i--);}else if (num >= 100){for (volatile int i = 63 * num - 90 * 4; i > 0; i--);}lua_pushinteger(L, 1);return 1;
}
#pragma GCC pop_options

  编写剩下的应用层代码，这个也需要做出小小的调整，我们需要根据返回的结果给上层推送不同的消息。不建议直接使用c库代码。

static int GetDS18B20Data(lua_State *L)
{uint8 pin = luaL_checkinteger(L, 1);int TempNum = 0;int data1 = 0, data2 = 0;char str1[10] = {0};char str2[10] = {0};char TempStr[20] = {0};uint8 var = 0;var = DS18B20_GetTemp_Num(pin, &TempNum);switch (var){case 0:data1 = TempNum / 10000;data2 = TempNum % 10000;itoa(data1, str1, 10);itoa(data2, str2, 10);sprintf(TempStr, "%s.%s C", str1, str2);lua_pushinteger(L, TempNum);lua_pushlstring(L, TempStr, strlen(TempStr) + 1);break;case 1:lua_pushinteger(L, 0xffff);lua_pushlstring(L, "[OneWire]TempStr=NULL", sizeof("[OneWire]TempStr=NULL"));break;case 2:lua_pushinteger(L, 0xffff);lua_pushlstring(L, "[OneWire]The pin passed in is not in the allowed range", sizeof("[OneWire]The pin passed in is not in the allowed range"));break;case 3:lua_pushinteger(L, 0xffff);lua_pushlstring(L, "[OneWire]DS18B20 was not detected", sizeof("[OneWire]DS18B20 was not detected"));break;}return 2;
}static int GetDHT11Data(lua_State *L)
{uint8 pin = luaL_checkinteger(L, 1);uint8 HumNum = 0, TemNum = 0;char str1[10] = {0};char str2[10] = {0};char HumStr[20] = {0};char TemStr[20] = {0};uint8 var = 0;var = DHT11_GetData_Num(pin, &HumNum, &TemNum);switch (var){case 0:itoa(HumNum, str1, 10);itoa(TemNum, str2, 10);char len = sprintf(HumStr, "%s%% RH", str1);HumStr[(int)len] = '\0';len = sprintf(TemStr, "%s C", str2);TemStr[(int)len] = '\0';lua_pushinteger(L, HumNum);lua_pushlstring(L, HumStr, strlen(HumStr) + 1);lua_pushinteger(L, TemNum);lua_pushlstring(L, TemStr, strlen(TemStr) + 1);break;case 1:lua_pushinteger(L, 0xffff);lua_pushlstring(L, "[OneWire]HumStr == NULL || TemStr == NULL", sizeof("[OneWire]HumStr == NULL || TemStr == NULL"));return 2;case 2:lua_pushinteger(L, 0xffff);lua_pushlstring(L, "[OneWire]The pin passed in is not in the allowed range", sizeof("[OneWire]The pin passed in is not in the allowed range"));return 2;case 3:lua_pushinteger(L, 0xffff);lua_pushlstring(L, "[OneWire]DHT11 was not detected", sizeof("[OneWire]DHT11 was not detected"));return 2;case 4:lua_pushinteger(L, 0xffff);lua_pushlstring(L, "[OneWire]Data verification error", sizeof("[OneWire]Data verification error"));return 2;}return 4;
}

  完整的c文件内容如下：

#include "lua.h"
#include "lualib.h"
#include "lauxlib.h"
#include "lplatform.h"
#include "auxmods.h"
#include "lrotable.h"
#include <string.h>
#include <stdlib.h>
#include <ctype.h>#include "OneWire.h"
#include "ds18b20.h"
#include "dht11.h"#pragma GCC push_options
#pragma GCC optimize("O0")
static int Delay1us(lua_State *L)
{uint32 num = luaL_checkinteger(L, 1);if (num >= 5 && num < 20){for (volatile int i = 60 * num - 70 * 4; i > 0; i--);}else if (num >= 20 && num < 100){for (volatile int i = 60 * num - 90 * 4; i > 0; i--);}else if (num >= 100){for (volatile int i = 63 * num - 90 * 4; i > 0; i--);}lua_pushinteger(L, 1);return 1;
}
#pragma GCC pop_options
static int GetDS18B20Data(lua_State *L)
{uint8 pin = luaL_checkinteger(L, 1);int TempNum = 0;int data1 = 0, data2 = 0;char str1[10] = {0};char str2[10] = {0};char TempStr[20] = {0};uint8 var = 0;var = DS18B20_GetTemp_Num(pin, &TempNum);switch (var){case 0:data1 = TempNum / 10000;data2 = TempNum % 10000;itoa(data1, str1, 10);itoa(data2, str2, 10);sprintf(TempStr, "%s.%s C", str1, str2);lua_pushinteger(L, TempNum);lua_pushlstring(L, TempStr, strlen(TempStr) + 1);break;case 1:lua_pushinteger(L, 0xffff);lua_pushlstring(L, "[OneWire]TempStr=NULL", sizeof("[OneWire]TempStr=NULL"));break;case 2:lua_pushinteger(L, 0xffff);lua_pushlstring(L, "[OneWire]The pin passed in is not in the allowed range", sizeof("[OneWire]The pin passed in is not in the allowed range"));break;case 3:lua_pushinteger(L, 0xffff);lua_pushlstring(L, "[OneWire]DS18B20 was not detected", sizeof("[OneWire]DS18B20 was not detected"));break;}return 2;
}static int GetDHT11Data(lua_State *L)
{uint8 pin = luaL_checkinteger(L, 1);uint8 HumNum = 0, TemNum = 0;char str1[10] = {0};char str2[10] = {0};char HumStr[20] = {0};char TemStr[20] = {0};uint8 var = 0;var = DHT11_GetData_Num(pin, &HumNum, &TemNum);switch (var){case 0:itoa(HumNum, str1, 10);itoa(TemNum, str2, 10);char len = sprintf(HumStr, "%s%% RH", str1);HumStr[(int)len] = '\0';len = sprintf(TemStr, "%s C", str2);TemStr[(int)len] = '\0';lua_pushinteger(L, HumNum);lua_pushlstring(L, HumStr, strlen(HumStr) + 1);lua_pushinteger(L, TemNum);lua_pushlstring(L, TemStr, strlen(TemStr) + 1);break;case 1:lua_pushinteger(L, 0xffff);lua_pushlstring(L, "[OneWire]HumStr == NULL || TemStr == NULL", sizeof("[OneWire]HumStr == NULL || TemStr == NULL"));return 2;case 2:lua_pushinteger(L, 0xffff);lua_pushlstring(L, "[OneWire]The pin passed in is not in the allowed range", sizeof("[OneWire]The pin passed in is not in the allowed range"));return 2;case 3:lua_pushinteger(L, 0xffff);lua_pushlstring(L, "[OneWire]DHT11 was not detected", sizeof("[OneWire]DHT11 was not detected"));return 2;case 4:lua_pushinteger(L, 0xffff);lua_pushlstring(L, "[OneWire]Data verification error", sizeof("[OneWire]Data verification error"));return 2;}return 4;
}static int IOIN(lua_State *L)
{uint8 pin = luaL_checkinteger(L, 1);lua_pushinteger(L, OneWire_IO_IN(pin));return 1;
}static int IOOUT(lua_State *L)
{uint8 pin = luaL_checkinteger(L, 1);OneWire_IO_OUT(pin);lua_pushinteger(L, 1);return 1;
}static int DQOUT(lua_State *L)
{uint8 pin = luaL_checkinteger(L, 1);uint8 level = luaL_checkinteger(L, 2);OneWire_DQ_OUT(pin, level);lua_pushinteger(L, 1);return 1;
}static int DQIN(lua_State *L)
{uint8 pin = luaL_checkinteger(L, 1);lua_pushinteger(L, OneWire_DQ_IN(pin));return 1;
}
#include "lrodefs.h"
const LUA_REG_TYPE OneWire_map[] = {{LSTRKEY("Delay1us"), LFUNCVAL(Delay1us)},{LSTRKEY("IOIN"), LFUNCVAL(IOIN)},{LSTRKEY("IOOUT"), LFUNCVAL(IOOUT)},{LSTRKEY("DQIN"), LFUNCVAL(DQIN)},{LSTRKEY("DQOUT"), LFUNCVAL(DQOUT)},{LSTRKEY("GetDS18B20Data"), LFUNCVAL(GetDS18B20Data)},{LSTRKEY("GetDHT11Data"), LFUNCVAL(GetDHT11Data)},{LNILKEY, LNILVAL}};LUALIB_API int luaopen_OneWire(lua_State *L)
{luaL_register(L, AUXLIB_OneWire, OneWire_map);return 1;
}

4.1.4、最后一步

  函数实现后，还剩下三件事，分别是：

  在modules下面的cmake文件中加入如下代码，将自己写的luaOneWire.c加入编译：

src/luaOneWire.c

  那就是链接OneWire库，在链接文件的后面加上库名称：

  添加OneWire头文件路径：

target_include_directories(${target} PRIVATE ../lib/OneWire)
target_include_directories(${target} PRIVATE ../lib/OneWire/ds18b20)
target_include_directories(${target} PRIVATE ../lib/OneWire/dht11)

  大概就加在这个地方，就行了。

4.1.5、编译一下看看

  没有错误，皆大欢喜 ̑̑ฅ( ˃̶˙ω˙˂̶ ฅ) ​​​

4.1.6、来跑一下

  来写一个脚本，跑一下看看，从gpio0读取ds18b20，从gpio1读取dht11。代码如下：

--必须在这个位置定义PROJECT和VERSION变量
--PROJECT：ascii string类型，可以随便定义，只要不使用,就行
--VERSION：ascii string类型，如果使用Luat物联云平台固件升级的功能，必须按照"X.X.X"定义，X表示1位数字；否则可随便定义
PROJECT = "LED"
VERSION = "0.0.1"
require "sys"
--加载日志功能模块，并且设置日志输出等级
--如果关闭调用log模块接口输出的日志，等级设置为log.LOG_SILENT即可
require "log"LOG_LEVEL = log.LOGLEVEL_TRACE
--[[
如果使用UART输出日志，打开这行注释的代码"--log.openTrace(true,1,115200)"即可，根据自己的需求修改此接口的参数
如果要彻底关闭脚本中的输出日志（包括调用log模块接口和Lua标准print接口输出的日志），执行log.openTrace(false,第二个参数跟调用openTrace接口打开日志的第二个参数相同)，例如：
1、没有调用过sys.opntrace配置日志输出端口或者最后一次是调用log.openTrace(true,nil,921600)配置日志输出端口，此时要关闭输出日志，直接调用log.openTrace(false)即可
2、最后一次是调用log.openTrace(true,1,115200)配置日志输出端口，此时要关闭输出日志，直接调用log.openTrace(false,1)即可
]]
--log.openTrace(true,1,115200)local function ds18b20_Task()local TempNum, TempStr = 0, 0while true doTempNum, TempStr = OneWire.GetDS18B20Data(0)if TempNum~=0xffff thenlog.info("ds18b20的值:", TempNum, TempStr)elselog.info("ds18b20读取出错:", TempStr)endsys.wait(1000)end
endlocal function dht11_Task()local  HumNum, HumStr, TemNum, TemStr = 0, 0, 0, 0while true doHumNum, HumStr, TemNum, TemStr = OneWire.GetDHT11Data(1)if HumNum~=0xffff thenlog.info("dht11:HumNum", HumNum)log.info("dht11:HumStr", HumStr)log.info("dht11:TemNum", TemNum)log.info("dht11:TemStr", TemStr)elselog.info("dht11读取出错:", HumStr)endsys.wait(3000)end
end
local function user_main()sys.wait(10000)sys.taskInit(ds18b20_Task)sys.taskInit(dht11_Task)
end--启动系统框架
sys.taskInit(user_main)
sys.init(0, 0)
sys.run()

  下架编译的固件和脚本后，打印结果如下。三秒采集一次dht11，一秒采集一次ds18b20，看起来还是很稳定的。没出现什么错误。

[2020-08-07 13:24:57.396] [I]-[dht11:HumNum] 78
[2020-08-07 13:24:57.396] [I]-[dht11:HumStr] 78RH
[2020-08-07 13:24:57.396] [I]-[dht11:TemNum] 28
[2020-08-07 13:24:57.396] [I]-[dht11:TemStr] 28 C
[2020-08-07 13:24:58.027] [I]-[ds18b20的值:] 271250 27.1250 C
[2020-08-07 13:24:59.035] [I]-[ds18b20的值:] 271250 27.1250 C
[2020-08-07 13:25:00.042] [I]-[ds18b20的值:] 270625 27.625 C
[2020-08-07 13:25:00.419] [I]-[dht11:HumNum] 78
[2020-08-07 13:25:00.419] [I]-[dht11:HumStr] 78RH
[2020-08-07 13:25:00.419] [I]-[dht11:TemNum] 28
[2020-08-07 13:25:00.419] [I]-[dht11:TemStr] 28 C
[2020-08-07 13:25:01.028] [I]-[ds18b20的值:] 271250 27.1250 C
[2020-08-07 13:25:02.048] [I]-[ds18b20的值:] 271250 27.1250 C
[2020-08-07 13:25:03.058] [I]-[ds18b20的值:] 271250 27.1250 C
[2020-08-07 13:25:03.445] [I]-[dht11:HumNum] 78
[2020-08-07 13:25:03.445] [I]-[dht11:HumStr] 78RH
[2020-08-07 13:25:03.849] [I]-[dht11:TemNum] 28
[2020-08-07 13:25:03.849] [I]-[dht11:TemStr] 28 C
[2020-08-07 13:25:04.048] [I]-[ds18b20的值:] 271250 27.1250 C
[2020-08-07 13:25:05.069] [I]-[ds18b20的值:] 271250 27.1250 C
[2020-08-07 13:25:06.063] [I]-[ds18b20的值:] 271250 27.1250 C
[2020-08-07 13:25:06.497] [I]-[dht11:HumNum] 78
[2020-08-07 13:25:06.500] [I]-[dht11:HumStr] 78RH
[2020-08-07 13:25:06.500] [I]-[dht11:TemNum] 28
[2020-08-07 13:25:06.500] [I]-[dht11:TemStr] 28 C
[2020-08-07 13:25:07.088] [I]-[ds18b20的值:] 271250 27.1250 C
[2020-08-07 13:25:08.076] [I]-[ds18b20的值:] 271250 27.1250 C
[2020-08-07 13:25:09.122] [I]-[ds18b20的值:] 271250 27.1250 C
[2020-08-07 13:25:09.528] [I]-[dht11:HumNum] 78
[2020-08-07 13:25:09.528] [I]-[dht11:HumStr] 78RH
[2020-08-07 13:25:09.528] [I]-[dht11:TemNum] 28
[2020-08-07 13:25:09.528] [I]-[dht11:TemStr] 28 C
[2020-08-07 13:25:10.095] [I]-[ds18b20的值:] 271250 27.1250 C
[2020-08-07 13:25:11.104] [I]-[ds18b20的值:] 271250 27.1250 C
[2020-08-07 13:25:12.114] [I]-[ds18b20的值:] 271250 27.1250 C
[2020-08-07 13:25:12.548] [I]-[dht11:HumNum] 78
[2020-08-07 13:25:12.548] [I]-[dht11:HumStr] 78RH
[2020-08-07 13:25:12.548] [I]-[dht11:TemNum] 28
[2020-08-07 13:25:12.548] [I]-[dht11:TemStr] 28 C
[2020-08-07 13:25:13.113] [I]-[ds18b20的值:] 271250 27.1250 C
[2020-08-07 13:25:14.121] [I]-[ds18b20的值:] 270625 27.625 C