From 3b51c2dac6a381ebde2cabcaab742a260954a85a Mon Sep 17 00:00:00 2001
From: jhchun <jh.chun@medithings.co.kr>
Date: Fri, 12 Jun 2026 12:11:34 +0900
Subject: [PATCH] =?UTF-8?q?dummy=20capture=205=ED=9A=8C=20=EC=B6=94?=
 =?UTF-8?q?=EA=B0=80?=
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---
 src/parser.c | 32 ++++++++++++++++++++++++++++++++
 1 file changed, 32 insertions(+)

diff --git a/src/parser.c b/src/parser.c
index 5dc8c43..5696d4c 100644
--- a/src/parser.c
+++ b/src/parser.c
@@ -46,6 +46,7 @@
 #define PIEZO_CFG_DELAY_MAX_US     100
 #define PIEZO_POST_SELECT_SETTLE_US  500
 #define PIEZO_AVG_INTER_BURST_GAP_US 500
+#define PIEZO_DUMMY_CAPTURE_COUNT    5
 
 static uint16_t piezo_channels[PIEZO_NUM_CHANNELS][ECHO_ADC_MAX_SAMPLES];
 static uint16_t echo_capture[ECHO_ADC_MAX_SAMPLES];
@@ -424,6 +425,22 @@ static int perform_piezo_sweep(void)
             return ECHO_STATUS_CAPTURE;
         }
 
+        for (uint8_t dummy = 0; dummy < PIEZO_DUMMY_CAPTURE_COUNT; dummy++)
+        {
+            k_busy_wait(PIEZO_AVG_INTER_BURST_GAP_US);
+            unsigned int key = irq_lock();
+            piezo_burst_sw((uint8_t)cfg->cycles);
+            k_busy_wait(capture_delay_us);
+
+            err = echo_adc_capture(echo_capture, cfg->samples);
+            irq_unlock(key);
+            if (err)
+            {
+                DBG_PRINTF("[ECHO] dummy capture fail ch=%d dummy=%d err=%d\r\n", ch, dummy, err);
+                return ECHO_STATUS_CAPTURE;
+            }
+        }
+
         memset(echo_accum, 0, sizeof(echo_accum));
 
         for (uint16_t avg = 0; avg < cfg->avg; avg++)
@@ -496,6 +513,21 @@ static int perform_single_piezo_capture(uint8_t cycles,
         return ECHO_STATUS_CAPTURE;
     }
 
+    for (uint8_t dummy = 0; dummy < PIEZO_DUMMY_CAPTURE_COUNT; dummy++)
+    {
+        k_busy_wait(PIEZO_AVG_INTER_BURST_GAP_US);
+        unsigned int key = irq_lock();
+        piezo_burst_sw(cycles);
+        k_busy_wait(delay_us);
+
+        err = echo_adc_capture(echo_capture, num_samples);
+        irq_unlock(key);
+        if (err)
+        {
+            return ECHO_STATUS_CAPTURE;
+        }
+    }
+
     memset(echo_accum, 0, sizeof(echo_accum));
 
     for (uint16_t avg = 0; avg < averaging; avg++)