ULTRASONIC INTERFACE USING TIMER

Hi Dialog,

我们的产品是盲人的障碍物检测。要升级到基于BLE的设备，我们选择DA14531模块。

组件是超声波传感器，蜂鸣器，触觉振动器，电池。

I'm trying to interface the following Ultrasonic sensor 400 S/T R 100. To generate 40 KHz burst of pulses, I configured timer 0 without PWM. I created a counter inside ISR of timer to generate transmission pulse. which I did it successfully(Refer attachment). Now after a delay of 1ms inside ISR , I'm calling adc_get_sample() function. From there I determine distance based on ultrasonic sensor principle. After running few iterations in keil debug mode .It got stuck in

static inline void dlg_error_isr(void)
{
ASSERT_WARNING(0);
}

in rwble.cThe project which is choose is BLE Barbone project. I have attached Trigger pulse generated with echo I got when obstacle is placed at 50 cm. As you can see the time interval is 3ms when coverted to distance is approx 51 cm. I have series of queries to implement this in code,

1. I'm not able to read ADC sample inside ISR.

2. What is the accuracy of your ADC ? w.r.to precision in milli voltage.

3.甚至when I run an ISR without any above functionality, I'm not able to connect to BLE scanner app.

Timer Configuration

// Enable the Timer0/Timer2 input clock
timer0_2_clk_enable();

timer0_init(TIM0_CLK_FAST, PWM_MODE_ONE, TIM0_CLK_NO_DIV);

// Set the Timer0/Timer2 input clock division factor to 2, so8 MHz输入时钟
timer0_2_clk_div_set（＆clk_div_config）;

// reload value for 12.5 micro second(T = 1/8 MHz * RELOAD_12.5_US = 0.125 * 100 = 12.5 micro second)
timer0_set_pwm_on_counter(TIMER_ON);
timer0_set_pwm_high_counter(NO_PWM);
timer0_set_pwm_low_counter（no_pwm）;
// register callback function for SWTIM_IRQn irq
timer0_register_callback(burst_user_callback_function);

// enable SWTIM_IRQn irq
timer0_enable_irq();

ADC配置

// adc configuration
adc_offset_calibrate(ADC_INPUT_MODE_SINGLE_ENDED);

adc_config_t echo_pin_cfg =
{
.input_mode = ADC_INPUT_MODE_SINGLE_ENDED,
.input = ADC_INPUT_SE_P0_6,
.smpl_time_mult = 2,
.continuous = false,
.interval_mult = 0,
.Input_attenuator = ADC_INPUT_ATTN_4X，
.chopping = false,
.oversampling = 0
};

adc_init(&echo_pin_cfg);

Could you assist me in integrating this sensor. I need to know how can I run a Timer ISR and BLE service at same time ?

问候，

BALAJI