diff --git a/firmware/application/src/app_cmd.c b/firmware/application/src/app_cmd.c
index 092d57e..a48b27e 100644
--- a/firmware/application/src/app_cmd.c
+++ b/firmware/application/src/app_cmd.c
@@ -488,6 +488,35 @@ static data_frame_tx_t *cmd_processor_mf1_write_one_block(uint16_t cmd, uint16_t
     return data_frame_make(cmd, status, 0, NULL);
 }
 
+#if defined(PROJECT_CHAMELEON_ULTRA)
+
+static data_frame_tx_t *cmd_processor_hf14a_set_field_on(uint16_t cmd, uint16_t status, uint16_t length, uint8_t *data) {
+    device_mode_t mode = get_device_mode();
+    if (mode != DEVICE_MODE_READER) {
+        return data_frame_make(cmd, STATUS_DEVICE_MODE_ERROR, 0, NULL);
+    }
+    
+    // Reset and turn on the antenna
+    pcd_14a_reader_reset();
+    pcd_14a_reader_antenna_on();
+    
+    return data_frame_make(cmd, STATUS_SUCCESS, 0, NULL);
+}
+
+static data_frame_tx_t *cmd_processor_hf14a_set_field_off(uint16_t cmd, uint16_t status, uint16_t length, uint8_t *data) {
+    device_mode_t mode = get_device_mode();
+    if (mode != DEVICE_MODE_READER) {
+        return data_frame_make(cmd, STATUS_DEVICE_MODE_ERROR, 0, NULL);
+    }
+    
+    // Turn off the antenna
+    pcd_14a_reader_antenna_off();
+    
+    return data_frame_make(cmd, STATUS_SUCCESS, 0, NULL);
+}
+
+#endif
+
 static data_frame_tx_t *cmd_processor_hf14a_raw(uint16_t cmd, uint16_t status, uint16_t length, uint8_t *data) {
     // Response Buffer
     uint8_t resp[DEF_FIFO_LENGTH] = { 0x00 };
@@ -1578,6 +1607,9 @@ static cmd_data_map_t m_data_cmd_map[] = {
     {    DATA_CMD_VIKING_SCAN,                  before_reader_run,           cmd_processor_viking_scan,                   NULL                   },
     {    DATA_CMD_VIKING_WRITE_TO_T55XX,        before_reader_run,           cmd_processor_viking_write_to_t55xx,         NULL                   },
 
+    {    DATA_CMD_HF14A_SET_FIELD_ON,           before_reader_run,           cmd_processor_hf14a_set_field_on,            NULL                   },
+    {    DATA_CMD_HF14A_SET_FIELD_OFF,          before_reader_run,           cmd_processor_hf14a_set_field_off,           NULL                   },
+
 #endif
 
     {    DATA_CMD_HF14A_GET_ANTI_COLL_DATA,     NULL,                        cmd_processor_hf14a_get_anti_coll_data,      NULL                   },
diff --git a/firmware/application/src/app_main.c b/firmware/application/src/app_main.c
index 87a3efc..77ee76f 100644
--- a/firmware/application/src/app_main.c
+++ b/firmware/application/src/app_main.c
@@ -41,6 +41,10 @@ NRF_LOG_MODULE_REGISTER();
 #include "tag_persistence.h"
 #include "settings.h"
 
+#if defined(PROJECT_CHAMELEON_ULTRA)
+#include "rc522.h"
+#endif
+
 // Defining soft timers
 APP_TIMER_DEF(m_button_check_timer); // Timer for button debounce
 
@@ -56,6 +60,9 @@ static bool m_is_a_btn_release = false;
 
 static bool m_system_off_processing = false;
 
+// NFC field generator state
+volatile bool m_is_field_on = false;  
+
 // cpu reset reason
 static uint32_t m_reset_source;
 static uint32_t m_gpregret_val;
@@ -139,6 +146,35 @@ static void gpio_te_init(void) {
     APP_ERROR_CHECK(err_code);
 }
 
+#if defined(PROJECT_CHAMELEON_ULTRA)
+static void field_generator_rainbow_loop(void) {
+    static uint8_t color_index = 0;
+    static uint32_t last_update = 0;
+    
+    if (!m_is_field_on) return;
+    
+    uint32_t now = app_timer_cnt_get();
+    
+    if (app_timer_cnt_diff_compute(now, last_update) < APP_TIMER_TICKS(100)) {
+        return;
+    }
+    last_update = now;
+    
+    // Rainbow colors
+    const uint8_t colors[] = {RGB_RED, RGB_YELLOW, RGB_GREEN, RGB_CYAN, RGB_BLUE, RGB_MAGENTA};
+    
+    set_slot_light_color(colors[color_index]);
+    uint32_t *led_pins = hw_get_led_array();
+    
+    // Light up all LEDs with current color
+    for (int i = 0; i < RGB_LIST_NUM; i++) {
+        nrf_gpio_pin_set(led_pins[i]);
+    }
+    
+    color_index = (color_index + 1) % 6;
+}
+#endif
+
 /**@brief Button Matrix Events
  */
 static void button_pin_handler(nrf_drv_gpiote_pin_t pin, nrf_gpiote_polarity_t action) {
@@ -162,7 +198,9 @@ static void timer_button_event_handle(void *arg) {
         NRF_LOG_INFO("BUTTON press during shutdown");
         return;
     }
+    
     nrf_drv_gpiote_pin_t pin = *(nrf_drv_gpiote_pin_t *)arg;
+    
     // Check here if the current GPIO is at the pressed level
     if (nrf_gpio_pin_read(pin) == 1) {
         if (pin == BUTTON_1) {
@@ -757,13 +795,67 @@ static void run_button_function_by_settings(settings_button_function_t sbf) {
         case SettingsButtonCloneIcUid:
             btn_fn_copy_ic_uid();
             break;
+        case SettingsButtonNfcFieldGenerator:
+            if (!m_is_field_on) {
+                // Initialize reader hardware if not already in reader mode
+                device_mode_t current_mode = get_device_mode();
+                if (current_mode != DEVICE_MODE_READER) {
+                    // Temporarily init reader hardware just for the field
+                    nrf_gpio_cfg_output(READER_POWER);
+                    nrf_gpio_pin_set(READER_POWER);     // reader power enable
+                    nrf_gpio_cfg_output(HF_ANT_SEL);
+                    nrf_gpio_pin_clear(HF_ANT_SEL);     // hf ant switch to reader mode
+                    
+                    pcd_14a_reader_init();
+                    bsp_delay_ms(10);
+                }
+                
+                pcd_14a_reader_reset();
+                pcd_14a_reader_antenna_on();
+                m_is_field_on = true;
+                NRF_LOG_INFO("NFC field ON");
+                
+                // Set initial rainbow state
+                set_slot_light_color(RGB_RED);
+                uint32_t *led_pins = hw_get_led_array();
+                for (int i = 0; i < RGB_LIST_NUM; i++) {
+                    nrf_gpio_pin_set(led_pins[i]);
+                }
+
+                // Stop sleep timer while field is active
+                NRF_LOG_INFO("Stopping sleep timer for field generator");
+                sleep_timer_stop();
+                NRF_LOG_INFO("Sleep timer stopped");
+            } else {
+                pcd_14a_reader_antenna_off();
+                m_is_field_on = false;
+                NRF_LOG_INFO("NFC field OFF");
+                
+                // If we're not in reader mode, clean up the hardware
+                device_mode_t current_mode = get_device_mode();
+                if (current_mode != DEVICE_MODE_READER) {
+                    pcd_14a_reader_uninit();
+                    nrf_gpio_pin_clear(READER_POWER);   // reader power disable
+                    nrf_gpio_pin_set(HF_ANT_SEL);       // hf ant switch back to tag mode
+                }
+                
+                // Restore normal LED
+                light_up_by_slot();
+
+                // Restart sleep timer
+                NRF_LOG_INFO("Field off, restarting sleep timer");
+                sleep_timer_start(SLEEP_DELAY_MS_BUTTON_CLICK);
+                NRF_LOG_INFO("Sleep timer restarted");
+            }
+            break;
 #endif
 
         case SettingsButtonShowBattery:
             show_battery();
+            break;
 
         default:
-            NRF_LOG_ERROR("Unsupported button function")
+            NRF_LOG_ERROR("Unsupported button function");
             break;
     }
 }
@@ -792,8 +884,10 @@ static void button_press_process(void) {
         }
         // Disable led marquee for usb at button pressed.
         g_usb_led_marquee_enable = false;
-        // Re-delay into hibernation
-        sleep_timer_start(SLEEP_DELAY_MS_BUTTON_CLICK);
+        // Re-delay into hibernation (unless field is on)
+        if (!m_is_field_on) {
+            sleep_timer_start(SLEEP_DELAY_MS_BUTTON_CLICK);
+        }
     }
 }
 
@@ -887,8 +981,17 @@ int main(void) {
         lesc_event_process();
         // Button event process
         button_press_process();
-        // Led blink at usb status
-        blink_usb_led_status();
+        
+#if defined(PROJECT_CHAMELEON_ULTRA)
+        // Field generator rainbow animation
+        field_generator_rainbow_loop();
+#endif
+        
+        // Led blink at usb status (only if field generator is off)
+        if (!m_is_field_on) {
+            blink_usb_led_status();
+        }
+        
         // Data pack process
         data_frame_process();
         // Log print process
@@ -902,4 +1005,4 @@ int main(void) {
         // Some task process done, we can enter cpu sleep state.
         sleep_system_run(system_off_enter, nrf_pwr_mgmt_run);
     }
-}
+}
\ No newline at end of file
diff --git a/firmware/application/src/data_cmd.h b/firmware/application/src/data_cmd.h
index e0bf70c..3aa1c82 100644
--- a/firmware/application/src/data_cmd.h
+++ b/firmware/application/src/data_cmd.h
@@ -73,6 +73,9 @@
 #define DATA_CMD_MF1_ENC_NESTED_ACQUIRE         (2014)
 #define DATA_CMD_MF1_CHECK_KEYS_ON_BLOCK        (2015)
 
+#define DATA_CMD_HF14A_SET_FIELD_ON             (2100)
+#define DATA_CMD_HF14A_SET_FIELD_OFF            (2101)
+
 //
 // ******************************************************************
 
diff --git a/firmware/application/src/rfid_main.c b/firmware/application/src/rfid_main.c
index 8899b8a..f93d448 100644
--- a/firmware/application/src/rfid_main.c
+++ b/firmware/application/src/rfid_main.c
@@ -2,11 +2,11 @@
 #include "rfid_main.h"
 #include "rgb_marquee.h"
 
-
-
 //The current mode of the device
 device_mode_t rfid_state = DEVICE_MODE_NONE;
 
+// External declaration for field state
+extern bool m_is_field_on;
 
 /**
  * @brief Function for enter tag reader mode
@@ -42,6 +42,12 @@ void tag_mode_enter(void) {
         rfid_state = DEVICE_MODE_TAG;
 
 #if defined(PROJECT_CHAMELEON_ULTRA)
+        // Safety check: turn off field if it's on
+        if (m_is_field_on) {
+            pcd_14a_reader_antenna_off();
+            m_is_field_on = false;
+        }
+        
         // uninit reader
         lf_125khz_radio_uninit();
         pcd_14a_reader_uninit();
@@ -116,4 +122,4 @@ uint8_t get_color_by_slot(uint8_t slot) {
     } else {    // Low -frequency emulation, return B
         return 2;
     }
-}
+}
\ No newline at end of file
diff --git a/firmware/application/src/settings.h b/firmware/application/src/settings.h
index 4231733..a690ea4 100644
--- a/firmware/application/src/settings.h
+++ b/firmware/application/src/settings.h
@@ -26,6 +26,8 @@ typedef enum {
     // Read the UID card number immediately after pressing, continue searching, and simulate immediately after reading the card
     SettingsButtonCloneIcUid = 3U,
     SettingsButtonShowBattery = 4U,
+    // Toggle NFC field generator on/off (Ultra only, must be in reader mode)
+    SettingsButtonNfcFieldGenerator = 5U,
 } settings_button_function_t;
 
 typedef struct ALIGN_U32 {
@@ -74,4 +76,4 @@ void settings_set_ble_connect_key(uint8_t *key);
 void settings_set_ble_pairing_enable(bool enable);
 bool settings_get_ble_pairing_enable(void);
 bool settings_get_ble_pairing_enable_first_load(void);
-#endif
+#endif
\ No newline at end of file
diff --git a/firmware/application/src/utils/syssleep.c b/firmware/application/src/utils/syssleep.c
index eaebf8d..69f8d2a 100644
--- a/firmware/application/src/utils/syssleep.c
+++ b/firmware/application/src/utils/syssleep.c
@@ -12,6 +12,7 @@ static volatile bool m_system_off_enter = false;
 
 extern bool g_is_ble_connected; //Link to log in BLE
 extern bool g_is_tag_emulating; //The status of the logo emulation card
+extern volatile bool m_is_field_on; //NFC field generator state from app_main.c
 
 
 /** @brief Equipment sleep timer event
@@ -48,8 +49,8 @@ void sleep_timer_start(uint32_t time_ms) {
     sleep_timer_stop();
     // Non -USB power supply status
     if (nrfx_power_usbstatus_get() == NRFX_POWER_USB_STATE_DISCONNECTED) {
-        // If Bluetooth is still connected, or is still in the state of emulation card, you don't need to start sleep
-        if (g_is_ble_connected == false && g_is_tag_emulating == false) {
+        // If Bluetooth is still connected, or is still in the state of emulation card, or field generator is on, you don't need to start sleep
+        if (g_is_ble_connected == false && g_is_tag_emulating == false && m_is_field_on == false) {
             // Start the timer
             ret_code_t err_code = app_timer_start(m_app_sleep_timer, APP_TIMER_TICKS(time_ms), NULL);
             APP_ERROR_CHECK(err_code);
@@ -72,4 +73,4 @@ void sleep_system_run(void (*sysOffSleep)(), void (*sysOnSleep)()) {
         // If no task can to process, we can sleep cpu sometime.
         sysOnSleep();
     }
-}
+}
\ No newline at end of file
diff --git a/software/script/chameleon_enum.py b/software/script/chameleon_enum.py
index f6b72ed..a66ebca 100644
--- a/software/script/chameleon_enum.py
+++ b/software/script/chameleon_enum.py
@@ -533,6 +533,7 @@ class ButtonPressFunction(enum.IntEnum):
     PREVSLOT = 2
     CLONE = 3
     BATTERY = 4
+    FIELDGEN = 5
 
     def __str__(self):
         if self == ButtonPressFunction.NONE:
@@ -545,9 +546,10 @@ class ButtonPressFunction(enum.IntEnum):
             return "Read then simulate the ID/UID card number"
         elif self == ButtonPressFunction.BATTERY:
             return "Show Battery Level"
+        elif self == ButtonPressFunction.FIELDGEN:
+            return "Toggle NFC Field Generator"
         return "None"
 
-
 @enum.unique
 class MfcValueBlockOperator(enum.IntEnum):
     DECREMENT = 0xC0