MUX setting 1.3ms delay -> TIMER4 기반 wait 방식으로 변경

- ADC 측정 값이 밀리는 현상 개선을 위함

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

@@ -638,7 +638,8 @@ dr_adc_err_t dr_adc_burst_capture_transmit(uint8_t freq_option, uint16_t delay_u
     nrf_delay_us(100);
 
     /*--- Step 2: Select piezo channel ---*/
-    dr_piezo_select_channel(piezo_ch);
+    dr_piezo_select_channel_start(piezo_ch);
+    dr_piezo_wait_mux_settled();
 
     /* dummy read after MUX switch to settle S/H capacitor */
     (void)spim_read_raw();
@@ -704,7 +705,8 @@ dr_adc_err_t dr_adc_burst_capture_transmit(uint8_t freq_option, uint16_t delay_u
 
             /* Re-select piezo channel before each burst
              * (burst functions may modify P1 port state) */
-            dr_piezo_select_channel(piezo_ch);
+            dr_piezo_select_channel_start(piezo_ch);
+            dr_piezo_wait_mux_settled();
 
             /* Execute piezo burst based on frequency option */
             switch (freq_option)
@@ -874,7 +876,8 @@ dr_adc_err_t dr_adc_capture_channel_only(uint8_t freq_option, uint16_t delay_us,
     //nrf_delay_us(100);
 
     /* channel select (MUX) : ~1.3 ms */
-    dr_piezo_select_channel(piezo_ch);
+    dr_piezo_select_channel_start(piezo_ch);
+    dr_piezo_wait_mux_settled();
 
     /* dummy read after MUX switch to settle S/H capacitor */
     (void)spim_read_raw();

project/ble_peripheral/ble_app_bladder_patch/measurement/piezo/dr_piezo.c

@@ -60,6 +60,8 @@
 #include "nrf_gpiote.h"
 #include "nrf_ppi.h"
 #include "nrf_delay.h"
+#include "nrfx_timer.h"
+#include "nrf_pwr_mgmt.h"
 #include "power_control.h"
 #include "app_util_platform.h"
 
@@ -126,6 +128,9 @@ static volatile uint8_t  m_remaining_cycles = 0;        /* remaining pulse cycle
 static uint32_t          m_period_ticks = PERIOD_TICKS_2MHZ; /* current period (timer ticks) */
 static bool              m_power_enabled = false;       /* DC/DC converter state */
 static bool              m_initialized = false;         /* driver initialised flag */
+static nrfx_timer_t      m_mux_settle_timer = NRFX_TIMER_INSTANCE(4);
+static volatile bool     m_mux_settle_done = true;
+static bool              m_mux_settle_timer_ready = false;
 
 /*==============================================================================
  * Timer2 IRQ handler
@@ -363,6 +368,63 @@ static void dr_piezo_ppi_init(void)
     nrf_ppi_channel_enable((nrf_ppi_channel_t)PPI_CH_N_OUT_TOGGLE_1);
 }
 
+static void dr_piezo_mux_settle_timeout_handler(nrf_timer_event_t event_type, void *p_context)
+{
+    (void)p_context;
+
+    if (event_type != NRF_TIMER_EVENT_COMPARE0)
+    {
+        return;
+    }
+
+    nrfx_timer_disable(&m_mux_settle_timer);
+    m_mux_settle_done = true;
+}
+
+static void dr_piezo_mux_timer_init(void)
+{
+    nrfx_err_t err;
+    nrfx_timer_config_t config = NRFX_TIMER_DEFAULT_CONFIG;
+
+    config.frequency = NRF_TIMER_FREQ_1MHz;
+    config.mode = NRF_TIMER_MODE_TIMER;
+    config.bit_width = NRF_TIMER_BIT_WIDTH_16;
+    config.interrupt_priority = APP_IRQ_PRIORITY_LOWEST;
+
+    err = nrfx_timer_init(&m_mux_settle_timer, &config, dr_piezo_mux_settle_timeout_handler);
+    if (err == NRFX_SUCCESS)
+    {
+        m_mux_settle_timer_ready = true;
+    }
+    else
+    {
+        m_mux_settle_timer_ready = false;
+        DBG_PRINTF("[DR_PIEZO] MUX settle timer init failed: %lu\r\n", (unsigned long)err);
+    }
+}
+
+static void dr_piezo_mux_timer_start(void)
+{
+    if (!m_mux_settle_timer_ready)
+    {
+        nrf_delay_us(DR_PIEZO_MUX_SETTLING_US);
+        m_mux_settle_done = true;
+        return;
+    }
+
+    m_mux_settle_done = false;
+    nrfx_timer_disable(&m_mux_settle_timer);
+    nrfx_timer_clear(&m_mux_settle_timer);
+    nrfx_timer_extended_compare(
+        &m_mux_settle_timer,
+        NRF_TIMER_CC_CHANNEL0,
+        nrfx_timer_us_to_ticks(&m_mux_settle_timer, DR_PIEZO_MUX_SETTLING_US),
+        NRF_TIMER_SHORT_COMPARE0_CLEAR_MASK,
+        true
+    );
+    nrfx_timer_enable(&m_mux_settle_timer);
+}
+
 /*==============================================================================
  * TX driver public functions
  *============================================================================*/
@@ -399,6 +461,13 @@ void dr_piezo_uninit(void)
     nrf_gpio_pin_clear(DR_PIEZO_PIN_DMP);
     nrf_gpio_pin_clear(DR_PIEZO_PIN_P_OUT);
     nrf_gpio_pin_clear(DR_PIEZO_PIN_N_OUT);
+
+    if (m_mux_settle_timer_ready)
+    {
+        nrfx_timer_disable(&m_mux_settle_timer);
+        nrfx_timer_uninit(&m_mux_settle_timer);
+        m_mux_settle_timer_ready = false;
+    }
     
     m_tx_active = false;
     m_initialized = false;
@@ -589,7 +658,7 @@ void dr_piezo_mux_init(void)
  *   CH3 = MUXA input3 (1,0,1,1)   CH7 = MUXB input3 (0,1,0,0)
  * MUX settling time (~1.3ms) required after channel switch.
  */
-void dr_piezo_select_channel(uint8_t channel)
+void dr_piezo_select_channel_start(uint8_t channel)
 {
     channel = channel & 0x07;  /* Mask to 0~7 range */
 
@@ -631,6 +700,27 @@ void dr_piezo_select_channel(uint8_t channel)
 
     /* MUX settling time required after channel change (> 1.2ms) */
     nrf_delay_us(DR_PIEZO_MUX_SETTLING_US);
+    /* Start one-shot timer for MUX settling (> 1.2ms). */
+    dr_piezo_mux_timer_start();
+}
+
+void dr_piezo_wait_mux_settled(void)
+{
+    while (!m_mux_settle_done)
+    {
+        nrf_pwr_mgmt_run();
+    }
+}
+
+bool dr_piezo_is_mux_settled(void)
+{
+    return m_mux_settle_done;
+}
+
+void dr_piezo_select_channel(uint8_t channel)
+{
+    dr_piezo_select_channel_start(channel);
+    dr_piezo_wait_mux_settled();
 }
 
 /* Pin test: toggle each signal pin HIGH/LOW in sequence (for oscilloscope verification) */

project/ble_peripheral/ble_app_bladder_patch/measurement/piezo/dr_piezo.h

@@ -95,11 +95,27 @@ void dr_piezo_test_pins(void);
 void dr_piezo_mux_init(void);
 
 /**
- * @brief Select piezo channel (0..7) via 8ch MUX
- * @note MUX settling time: ~1.3 ms delay after switching
+ * @brief Select piezo channel and wait for MUX settling
+ * @note Uses a one-shot timer for the ~1.3 ms settling interval.
  */
 void dr_piezo_select_channel(uint8_t channel);
 
+/**
+ * @brief Select piezo channel and start MUX settling timer
+ * @note Does not wait for settling to complete.
+ */
+void dr_piezo_select_channel_start(uint8_t channel);
+
+/**
+ * @brief Wait until the outstanding MUX settling interval completes
+ */
+void dr_piezo_wait_mux_settled(void);
+
+/**
+ * @brief Check whether the current MUX settling interval has completed
+ */
+bool dr_piezo_is_mux_settled(void);
+
 /*==============================================================================
  * System functions (power + TX combined)
  *============================================================================*/