MUX 전환 후 ch0 더미 측정 6회 추가

- ch0,1,2에 발생하는 노이즈 해소를 위함
- 약 10ms 정도 측정 시간 증가

project/ble_peripheral/ble_app_bladder_patch/measurement/adc121s051/dr_adc121s051.c

@@ -1274,6 +1274,7 @@ dr_adc_err_t maa_async_start(uint8_t freq_option, uint16_t delay_us, uint16_t nu
 {
     dr_adc_err_t err;
     uint8_t ch;
+    dr_maa_channel_t discard_channel;
 
     if (g_maa_ctx.state != MAA_ASYNC_IDLE)
     {
@@ -1308,6 +1309,30 @@ dr_adc_err_t maa_async_start(uint8_t freq_option, uint16_t delay_us, uint16_t nu
     /* capture all channels without BLE TX, then start transmission */
     g_maa_ctx.state = MAA_ASYNC_CAPTURING;
 
+    /* Warm up CH0 6 times and discard the results before the real capture starts. */
+    for (uint8_t warmup = 0; warmup < 6; warmup++)
+    {
+        err = dr_adc_capture_channel_only(
+            g_maa_ctx.freq_option,
+            g_maa_ctx.delay_us,
+            g_maa_ctx.num_samples,
+            g_maa_ctx.cycles,
+            1,
+            0,
+            &discard_channel
+        );
+        if (err != DR_ADC_OK)
+        {
+            if (g_plat.log)
+            {
+                g_plat.log("[maa] warmup CH0 failed (%d)", err);
+            }
+            dr_piezo_power_off();
+            g_maa_ctx.state = MAA_ASYNC_IDLE;
+            return err;
+        }
+    }
+
     for (ch = 0; ch < MAA_NUM_CHANNELS; ch++)
     {
         err = maa_async_capture_channel(ch);