【AT-START-F425测评】 五、定时器中断代码简析及呼吸灯实现
<p>雅特力AT32提供了较完整的Demo例程，其中tmr例程还是非常丰富的，其中有个7_pwm_output的例程，7个管脚分别输出PWM。Readme文件中有英文说明</p><p> - tmr1_ch1 ---> pa8<br />
- tmr1_ch1c ---> pb13<br />
- tmr1_ch2 ---> pa9<br />
- tmr1_ch2c ---> pb14<br />
- tmr1_ch3 ---> pa10<br />
- tmr1_ch3c ---> pb15<br />
- tmr1_ch4 ---> pa11</p>
<p>查询手册，可以看到定时器各管脚的复用情况</p>
<p> 可以看到，复用使用MUX2。</p>
<p>具体的代码部分为</p>
<pre>
<code>int main(void)
{
uint8_tdir = 0;
system_clock_config();
at32_board_init();
/* get system clock */
crm_clocks_freq_get(&crm_clocks_freq_struct);
/* turn led2/led3/led4 on */
at32_led_on(LED2);
at32_led_on(LED3);
at32_led_on(LED4);
/* enable tmr1/gpioa/gpiob clock */
crm_periph_clock_enable(CRM_TMR1_PERIPH_CLOCK, TRUE);
crm_periph_clock_enable(CRM_GPIOA_PERIPH_CLOCK, TRUE);
//crm_periph_clock_enable(CRM_GPIOB_PERIPH_CLOCK, TRUE);
/* timer1 output pin Configuration */
gpio_init_struct.gpio_pins = GPIO_PINS_8 | GPIO_PINS_9 | GPIO_PINS_10 |GPIO_PINS_11;
gpio_init_struct.gpio_mode = GPIO_MODE_MUX;
gpio_init_struct.gpio_out_type = GPIO_OUTPUT_PUSH_PULL;
gpio_init_struct.gpio_pull = GPIO_PULL_NONE;
gpio_init_struct.gpio_drive_strength = GPIO_DRIVE_STRENGTH_STRONGER;
gpio_init(GPIOA, &gpio_init_struct);
//gpio_init_struct.gpio_pins = GPIO_PINS_13 | GPIO_PINS_14 | GPIO_PINS_15;
//gpio_init_struct.gpio_mode = GPIO_MODE_MUX;
//gpio_init_struct.gpio_out_type = GPIO_OUTPUT_PUSH_PULL;
//gpio_init_struct.gpio_pull = GPIO_PULL_NONE;
//gpio_init_struct.gpio_drive_strength = GPIO_DRIVE_STRENGTH_STRONGER;
//gpio_init(GPIOB, &gpio_init_struct);
gpio_pin_mux_config(GPIOA, GPIO_PINS_SOURCE8, GPIO_MUX_2);
gpio_pin_mux_config(GPIOA, GPIO_PINS_SOURCE9, GPIO_MUX_2);
gpio_pin_mux_config(GPIOA, GPIO_PINS_SOURCE10, GPIO_MUX_2);
gpio_pin_mux_config(GPIOA, GPIO_PINS_SOURCE11, GPIO_MUX_2);
//gpio_pin_mux_config(GPIOB, GPIO_PINS_SOURCE13, GPIO_MUX_2);
//gpio_pin_mux_config(GPIOB, GPIO_PINS_SOURCE14, GPIO_MUX_2);
//gpio_pin_mux_config(GPIOB, GPIO_PINS_SOURCE15, GPIO_MUX_2);
/* tmr1 configuration generate 7 pwm signals with 4 different duty cycles:
prescaler = 0, tmr1 counter clock = system_core_clock
the objective is to generate 7 pwm signal at 17.57 khz:
- tim1_period = (system_core_clock / 17570) - 1
the channel 1 and channel 1c duty cycle is set to 50%
the channel 2 and channel 2c duty cycle is set to 37.5%
the channel 3 and channel 3c duty cycle is set to 25%
the channel 4 duty cycle is set to 12.5%
the timer pulse is calculated as follows:
- channelxpulse = duty_cycle * (tim1_period - 1) / 100 */
//类似stm32的ARR，自动重新装载寄存器
/* compute the value to be set in arr regiter to generate signal frequency at 17.57 khz */
//timer_period = (crm_clocks_freq_struct.sclk_freq / 17570 ) - 1;
//一下分别根据周期计算占空比
/* compute c1dt value to generate a duty cycle at 50% for channel 1 and 1c */
// channel1_pulse = (uint16_t)(((uint32_t) 5 * (timer_period - 1)) / 10);
/* compute c2dt value to generate a duty cycle at 37.5%for channel 2 and 2c */
//channel2_pulse = (uint16_t)(((uint32_t) 375 * (timer_period - 1)) / 1000);
/* compute c3dt value to generate a duty cycle at 25%for channel 3 and 3c */
//channel3_pulse = (uint16_t)(((uint32_t) 2 * (timer_period - 1)) / 100);
/* compute c4dt value to generate a duty cycle at 12.5%for channel 4 */
//channel4_pulse = (uint16_t)(((uint32_t) 125 * (timer_period- 1)) / 1000);
//原代码直接用系统主频进行计数，不分频
//tmr_base_init(TMR1, timer_period, 0);
//更改为分频96，及定时器主频为96Mhz / (95 +1) = 1Mhz
//更改Arr 为 500， 实际计数为501个
tmr_base_init(TMR1,500,95);
tmr_cnt_dir_set(TMR1, TMR_COUNT_UP); //向上计数方式
tmr_clock_source_div_set(TMR1, TMR_CLOCK_DIV1); //采用预分频的频率
/* channel 1, 2, 3 and 4 configuration in output mode */
tmr_output_default_para_init(&tmr_output_struct);
tmr_output_struct.oc_mode = TMR_OUTPUT_CONTROL_PWM_MODE_B;
tmr_output_struct.oc_output_state = TRUE;
tmr_output_struct.oc_polarity = TMR_OUTPUT_ACTIVE_LOW;
tmr_output_struct.oc_idle_state = TRUE;
tmr_output_struct.occ_output_state = TRUE;
tmr_output_struct.occ_polarity = TMR_OUTPUT_ACTIVE_HIGH;
tmr_output_struct.occ_idle_state = FALSE;
// channel 1通道1配置，以及设置占空比
tmr_output_channel_config(TMR1, TMR_SELECT_CHANNEL_1, &tmr_output_struct);
tmr_channel_value_set(TMR1, TMR_SELECT_CHANNEL_1, channel1_pulse);
// channel 2通道2配置，以及设置占空比
tmr_output_channel_config(TMR1, TMR_SELECT_CHANNEL_2, &tmr_output_struct);
tmr_channel_value_set(TMR1, TMR_SELECT_CHANNEL_2, channel2_pulse);
// channel 3通道3配置，以及设置占空比
tmr_output_channel_config(TMR1, TMR_SELECT_CHANNEL_3, &tmr_output_struct);
tmr_channel_value_set(TMR1, TMR_SELECT_CHANNEL_3, channel3_pulse);
// channel 4通道4配置，以及设置占空比
tmr_output_channel_config(TMR1, TMR_SELECT_CHANNEL_4, &tmr_output_struct);
tmr_channel_value_set(TMR1, TMR_SELECT_CHANNEL_4, channel4_pulse);
/* output enable */
tmr_output_enable(TMR1, TRUE);
/* enable tmr1 */
tmr_counter_enable(TMR1, TRUE);
channel3_pulse = 100;
while(1)
{
//设置呼吸方式，最大值时递减，最小值时递增
if(dir)channel3_pulse++;
else channel3_pulse--;
if(channel3_pulse>=500)dir=0;
if(channel3_pulse==0)dir=1;
//赋值占空比
TMR1->c3dt = channel3_pulse;
delay_ms(2);
}
}</code></pre>
<p>用的是高级定时器TMR1实现的。</p>
<p> </p>
<p>评测的时候发现PA11没有占空比信号，通过万用表检测，发现排针（PA11）和MCU的管脚之间断开了，不知道是什么原因，个人在使用过程中对开发板的保护还是蛮好的，由此推断应该是出厂没有完全检测管脚，也给厂家提个醒。</p>
<p>建议收到，期待后续：）</p>
旁边这个是神马神器呀，看着有点象ESP8266？ <p>板子不良？作为评估板这有点尴尬了。</p>
lugl4313820 发表于 2022-4-29 09:27
旁边这个是神马神器呀，看着有点象ESP8266？
<p>网友火眼金睛啊，旁边是自己设计的stm32的开发板底板，确实用了8266。</p>
<p>用镊子拨一下PA11引脚，看会不会变形，一搬LQFP封装没焊好用这种方法能试出来。</p>
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