BLE-NRF51822教程8-软件定时器的使用

ゞ浴缸里的玫瑰 2022-07-13 09:21 210阅读 0赞

本讲教程还是会基于 9.0 sdk中的uart例子。 在该例子上使用 sdk中自带的软件定时器来实现一些功能

Uart例子在sdk 中如下目录

XXX\\Keil\_v5\\ARM\\Pack\\NordicSemiconductor\\nRF\_Examples\\9.0.0\\ble\_peripheral\\ble\_app\_uart

首先 了解一下相关API

Sdk中的app timer（软件定时器） 是用51822中的RTC来模拟出的一个定时器队列来实现通过一个硬件RTC来模拟多个软件定时器。

使用app timer模块之前需要调用

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 <td style="word-wrap:break-word; margin:0px; padding:0px"> uint32_t app_timer_init </td> 
 <td style="word-wrap:break-word; margin:0px; padding:0px"> ( </td> 
 <td style="word-wrap:break-word; margin:0px; padding:0px"> uint32_t&nbsp; </td> 
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 <td style="word-wrap:break-word; margin:0px; padding:0px"> <a style="word-wrap:break-word; text-decoration:none; color:rgb(25,89,155)" rel="nofollow">app_timer_evt_schedule_func_t</a>&nbsp; </td> 
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来初始化模块，通常都不直接使用该函数，而是使用SDK中提供的宏。

这个宏会根据帮你的参数申请合适的buff然后再调用app\_timer\_init函数

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 <td style="word-wrap:break-word; margin:0px; padding:0px"> #define APP_TIMER_INIT </td> 
 <td style="word-wrap:break-word; margin:0px; padding:0px"> ( </td> 
 <td style="word-wrap:break-word; margin:0px; padding:0px"> &nbsp; </td> 
 <td style="word-wrap:break-word; margin:0px; padding:0px"> PRESCALER, </td> 
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 <td style="word-wrap:break-word; margin:0px; padding:0px"> </td> 
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 <td style="word-wrap:break-word; margin:0px; padding:0px"> &nbsp; </td> 
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 <td style="word-wrap:break-word; margin:0px; padding:0px">&nbsp;</td> 
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 <td style="word-wrap:break-word; margin:0px; padding:0px"> &nbsp; </td> 
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 <td style="word-wrap:break-word; margin:0px; padding:0px"> SCHEDULER_FUNC&nbsp; </td> 
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Value:

do                                                                 \\

\{                                                                        \\

static uint32\_t APP\_TIMER\_BUF\[CEIL\_DIV(APP\_TIMER\_BUF\_SIZE((MAX\_TIMERS), \\

(OP\_QUEUES\_SIZE) + 1), \\

sizeof(uint32\_t))\]; \\

uint32\_t ERR\_CODE = app\_timer\_init((PRESCALER), \\

(MAX\_TIMERS), \\

(OP\_QUEUES\_SIZE) + 1, \\

APP\_TIMER\_BUF, \\

SCHEDULER\_FUNC); \\

APP\_ERROR\_CHECK(ERR\_CODE); \\

\} while (0)

然后就可以创建自己的定时器了。

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 <td style="word-wrap:break-word; margin:0px; padding:0px"> uint32_t app_timer_create </td> 
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 <td style="word-wrap:break-word; margin:0px; padding:0px"> <a style="word-wrap:break-word; text-decoration:none; color:rgb(25,89,155)" rel="nofollow">app_timer_id_t</a>&nbsp;*&nbsp; </td> 
 <td style="word-wrap:break-word; margin:0px; padding:0px"> p_timer_id, </td> 
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 <td style="word-wrap:break-word; margin:0px; padding:0px"> <a style="word-wrap:break-word; text-decoration:none; color:rgb(25,89,155)" rel="nofollow">app_timer_mode_t</a>&nbsp; </td> 
 <td style="word-wrap:break-word; margin:0px; padding:0px"> mode, </td> 
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 <td style="word-wrap:break-word; margin:0px; padding:0px"> <a style="word-wrap:break-word; text-decoration:none; color:rgb(25,89,155)" rel="nofollow">app_timer_timeout_handler_t</a>&nbsp; </td> 
 <td style="word-wrap:break-word; margin:0px; padding:0px"> timeout_handler&nbsp; </td> 
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可以通过mode模式来选择是只运行一次还是周期性的定时器。

APP\_TIMER\_MODE\_SINGLE\_SHOT,

APP\_TIMER\_MODE\_REPEATED

Timeout\_handler为注册的回调函数，在定时到期后执行

定时器创建完成后需要主动调用开始函数

uint32\_t app\_timer\_start(app\_timer\_id\_t timer\_id,uint32\_t timeout\_ticks,void \* p\_context )

定时时间 timeout\_ticks 需要通过宏 APP\_TIMER\_TICKS(MS, PRESCALER) 来或得，MS为需要定时的ms数, PRESCALER就是上面的 初始化模块时的参数PRESCALER。

P\_context 为传递给回调函数的参数。 在定时到期执行定时函数时这个参数会作为他的参数

下面我们在uart工程的基础上创建一个定时器，这个定时器在手机使能了rx特征值的notify功能后启动，然后周期性的递增发送一个数据给手机

Uart工程中 app timer模块的初始化已经有了，我们只要创建一个定时器然后在手机使能notify时开启他就行了。

添加如下变量和函数。

app\_timer\_id\_t my\_test\_timer;

uint8\_t g\_send\_data = 0;

void my\_timer\_handler(void \*params)\{

ble\_nus\_string\_send(&m\_nus, &g\_send\_data, 1);

g\_send\_data++;

修改main函数，初始化最后创建定时器。

int main(void)

uint32\_t err\_code;

bool erase\_bonds;

uint8\_t  start\_string\[\] = START\_STRING;

// Initialize.

APP\_TIMER\_INIT(APP\_TIMER\_PRESCALER,APP\_TIMER\_MAX\_TIMERS,APP\_TIMER\_OP\_QUEUE\_SIZE, false);                    //原工程中已经初始化了app timer模块

uart\_init();

buttons\_leds\_init(&erase\_bonds);

ble\_stack\_init();

gap\_params\_init();

services\_init();

advertising\_init();

conn\_params\_init();

printf("start");

err\_code = ble\_advertising\_start(BLE\_ADV\_MODE\_FAST);

APP\_ERROR\_CHECK(err\_code);

//添加创建定时器代码

err\_code = app\_timer\_create(&my\_test\_timer,

APP\_TIMER\_MODE\_REPEATED,

my\_timer\_handler);

printf("create timere err\_code:%d\\r\\n",err\_code);

// Enter main loop.

for (;;)

power\_manage();

然后 在 ble\_nus.c 中 找到on\_write函数添加红色部分

extern app\_timer\_id\_t my\_test\_timer;  //声明下变量

static void on\_write(ble\_nus\_t \* p\_nus, ble\_evt\_t \* p\_ble\_evt)

int err\_code;

ble\_gatts\_evt\_write\_t \* p\_evt\_write = &p\_ble\_evt->evt.gatts\_evt.params.write;

if ( (p\_evt\_write->handle == p\_nus->rx\_handles.cccd\_handle)&&(p\_evt\_write->len == 2))

if (ble\_srv\_is\_notification\_enabled(p\_evt\_write->data))

p\_nus->is\_notification\_enabled = true;

//定时1s，   PRESCALER直接填 0

app\_timer\_start(my\_test\_timer,  APP\_TIMER\_TICKS(1000, 0), NULL);

else

p\_nus->is\_notification\_enabled = false;

else if ((p\_evt\_write->handle == p\_nus->tx\_handles.value\_handle)

&&(p\_nus->data\_handler != NULL)

)

……………………………………….

else

// Do Nothing. This event is not relevant for this service.

现在下载程序后，手机连接，然后点使能Notify后就能周期收到数据了。

如果创建timer出错。是允许创建的定时器已经达到最大值了，可以修改一下宏。

Main.c中的

\#define APP\_TIMER\_MAX\_TIMERS            (3 + BSP\_APP\_TIMERS\_NUMBER)

将原来的2 改为3 如果想创建更多的定时器，同样也要改大这里的值

BLE-NRF51822教程8-软件定时器的使用

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