diff --git a/edc20_cycle_iv_mode.c b/edc20_cycle_iv_mode.c
index d1a4fa1..330b0d9 100644
--- a/edc20_cycle_iv_mode.c
+++ b/edc20_cycle_iv_mode.c
@@ -114,13 +114,13 @@ static ret_code_t _send_data_packet(elite_notify_packet_t *p_notify_buf, bool is
 
 typedef struct
 {
-    int32_t dir;
+    float dir;
     float mV_output;
     float mV_max;
     float mV_min;
     float mV_start;
     float mV_stop;
-    uint32_t step;
+    float step;
     uint32_t cycle_cnt;
     uint32_t cycle_max;
     uint32_t fullscale;
@@ -168,13 +168,12 @@ static uint32_t mV_out_1(cycle_iv_dac_t *p)
 
 static uint32_t cal_dac_timer_interval(elite_dac_config_t *p_config, cycle_iv_dac_t *p_cycle_iv_dac)
 {
-    const float STEP_TIME_FACTOR = 2.0f;
     uint32_t intvl;
-    uint32_t step_time = p_config->uS_step * STEP_TIME_FACTOR;
-    for (uint32_t intvl = 100; intvl < 1000000; intvl *= 10)
+    float step_time = p_config->uS_step;
+    for (intvl = 100; intvl < 1000000; intvl *= 10)
     {
         p_cycle_iv_dac->step = (p_config->mV_step * intvl) / step_time;
-        if (p_cycle_iv_dac->step)
+        if (p_cycle_iv_dac->step >= 0.001)
         {
             return intvl;
         }
@@ -295,45 +294,44 @@ static void edc20_cycle_iv_mode_task(void *p_arg)
         NRF_LOG_INFO("%s", info);
     }
 
-       dac_write_through(OUT_0, mV_out_0(&dac_param));
-       dac_write_through(OUT_1, mV_out_1(&dac_param));
-       circuit_selection_dac_fune_tune_f0();
+    dac_write_through(OUT_0, mV_out_0(&dac_param));
 
+    dac_param.mV_output = dac_param.mV_start;
+    dac_write_through(OUT_1, mV_out_1(&dac_param));
 
+    circuit_selection_dac_fune_tune_f0();
 
+    /* start DAC timer */
+    edc20_dac_tim_start(cal_dac_timer_interval(&mode_param.config, &dac_param), _callback, &dac_param);
 
-    
-       /* start DAC timer */
-       edc20_dac_tim_start(cal_dac_timer_interval(&mode_param.config, &dac_param), _callback, &dac_param);
-    
-       /* start ADC timer */
-       edc20_adc_tim_start(&mode_param.config);
-    
-       /* get current tick */
-       TickType_t tick = xTaskGetTickCount();
-    
-       uint32_t notify_delay = pdMS_TO_TICKS(mode_param.mS_period);
-    
-       /* start data update process */
-       running = true;
-    
-       while (running)
-       {
-           ret_code_t ret = _send_data_packet(&packet_buf, false);
-           switch (ret)
-           {
-               case NRF_SUCCESS:
-               case NRF_ERROR_RESOURCES:
-                   vTaskDelayUntil(&tick, notify_delay);
-                   break;
-               default:
-                   running = false;
-                   break;
-           }
-       }
-    
-       edc20_dac_tim_stop();
-       edc20_adc_tim_stop();
+    /* start ADC timer */
+    edc20_adc_tim_start(&mode_param.config);
+
+    /* get current tick */
+    TickType_t tick = xTaskGetTickCount();
+
+    uint32_t notify_delay = pdMS_TO_TICKS(mode_param.mS_period);
+
+    /* start data update process */
+    running = true;
+
+    while (running)
+    {
+        ret_code_t ret = _send_data_packet(&packet_buf, false);
+        switch (ret)
+        {
+            case NRF_SUCCESS:
+            case NRF_ERROR_RESOURCES:
+                vTaskDelayUntil(&tick, notify_delay);
+                break;
+            default:
+                running = false;
+                break;
+        }
+    }
+
+    edc20_dac_tim_stop();
+    edc20_adc_tim_stop();
 
     if (1)
     {