Tidy up ble pointer example

Author: peterharperuk

bluetooth/ble_pointer/CMakeLists.txt

@@ -1,37 +1,33 @@
 # Add mpu6050 libary
 add_library(mpu6050_i2c_lib INTERFACE)
 target_sources(mpu6050_i2c_lib INTERFACE
-        ${CMAKE_CURRENT_LIST_DIR}/mpu6050_i2c_lib.c
-        )
+    ${CMAKE_CURRENT_LIST_DIR}/mpu6050_i2c_lib.c
+)
 target_include_directories(mpu6050_i2c_lib INTERFACE
-        ${CMAKE_CURRENT_LIST_DIR}
-        )
+    ${CMAKE_CURRENT_LIST_DIR}
+)
 target_link_libraries(mpu6050_i2c_lib INTERFACE
     pico_stdlib
     hardware_i2c
-        )
+)
 
-# Add executable. Default name is the project name, version 0.1
 add_executable(ble_pointer 
     ble_pointer.c
-    )
-
-# Add the standard library to the build
+)
 target_link_libraries(ble_pointer
     pico_stdlib
     pico_btstack_ble
     pico_btstack_cyw43
     pico_cyw43_arch_none
     mpu6050_i2c_lib
-    )
-
-# Add the standard include files to the build
+)
 target_include_directories(ble_pointer PRIVATE
     ${CMAKE_CURRENT_LIST_DIR}
     ${CMAKE_CURRENT_LIST_DIR}/..
-    )
-
+)
+target_compile_definitions(ble_pointer PRIVATE
+    #WANT_HCI_DUMP=1
+)
 pico_btstack_make_gatt_header(ble_pointer PRIVATE "${CMAKE_CURRENT_LIST_DIR}/ble_pointer.gatt")
-
 pico_add_extra_outputs(ble_pointer)
 

bluetooth/ble_pointer/README.md

@@ -2,6 +2,6 @@
 
 This example is based on BTstack's 'hog_mouse_demo' and demonstrates a Bluetooth HID mouse. Cursor position is controlled by mpu6050 angle measurements, allowing you to point at the screen and move the mouse cursor. 
 
-To use this example connect a mpu6050 (which can be found at https://thepihut.com/products/6-dof-sensor-mpu6050) to the pico, with SDA connected to pin 4 and SCL connected to pin 5. Also, connect 2 buttons to pins 15 and 16 for left and right click.
+To use this example connect a mpu6050 (which can be found at https://thepihut.com/products/6-dof-sensor-mpu6050) to the pico, with SDA connected to pin 4 and SCL connected to pin 5. Also, connect 2 buttons to pins 15 and 16 and ground for left and right click.
 
 Once powered, you should be able to pair your computer with 'HID Mouse' and use the pointer. 

bluetooth/ble_pointer/ble_pointer.c

@@ -35,13 +35,6 @@
  *
  */
 
-//#define BTSTACK_FILE__ "hog_mouse_demo.c"
-
-// *****************************************************************************
-/* EXAMPLE_START(hog_mouse_demo): HID Mouse LE
- */
-// *****************************************************************************
-
 #include <stdint.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -67,6 +60,18 @@
 #include <mpu6050_i2c_lib.h>
 #include <math.h>
 
+#if !defined(i2c_default) || !defined(PICO_DEFAULT_I2C_SDA_PIN) || !defined(PICO_DEFAULT_I2C_SCL_PIN)
+#error Example requires a board with I2C pins
+#endif
+
+#ifndef NDEBUG
+#define DEBUG_LOG(...) printf(__VA_ARGS__)
+#else
+#define DEBUG_LOG(...)
+#endif
+#define INFO_LOG printf
+#define ERROR_LOG printf
+
 #define ALPHA 0.05 // for complimentary filter, big alpha gives faster reponse but more noise
 
 // FS values are 0, 1, 2, or 3
@@ -78,21 +83,44 @@
 // how many readings taken to find gyro offsets
 #define OFFSET_NUM 10000
 
-//pins for buttons
+// pins for buttons
+#ifndef LEFT_BUTTON_GPIO_NUM
 #define LEFT_BUTTON_GPIO_NUM 15
+#endif
+
+#ifndef RIGHT_BUTTON_GPIO_NUM
 #define RIGHT_BUTTON_GPIO_NUM 16
+#endif
+
+#ifndef MOUSE_PERIOD_MS
+#define MOUSE_PERIOD_MS 15
+#endif
+
+#ifndef SCREEN_WIDTH
+#define SCREEN_WIDTH 1920
+#endif
+
+#ifndef SCREEN_HEIGHT
+#define SCREEN_HEIGHT 1080
+#endif
 
-float roll;
-float pitch;
-float yaw;
+static float roll;
+static float pitch;
+static float yaw;
 
-float roll_offset;
-float pitch_offset;
-float yaw_offset;
+static float roll_offset;
+static float pitch_offset;
+static float yaw_offset;
 
 // start in top left corner
-int abs_x = 0;
-int abs_y = 0;
+static int abs_x = 0;
+static int abs_y = 0;
+
+static int dx;
+static int dy;
+static uint8_t buttons;
+static btstack_timer_source_t mousing_timer;
+static int mouse_active = 0;
 
 // from USB HID Specification 1.1, Appendix B.2
 const uint8_t hid_descriptor_mouse_boot_mode[] = {
@@ -160,7 +188,7 @@ static void hog_mouse_setup(void){
 
     // initialize CYW43 driver architecture (will enable BT if/because CYW43_ENABLE_BLUETOOTH == 1)
     if (cyw43_arch_init()) {
-        printf("failed to initialise cyw43_arch\n");
+        ERROR_LOG("failed to initialise cyw43_arch\n");
     }
 
     // setup l2cap
@@ -222,21 +250,11 @@ static void send_report(uint8_t buttons, int8_t dx, int8_t dy){
     }
 }
 
-static int dx;
-static int dy;
-static uint8_t buttons;
-
-#define MOUSE_PERIOD_MS 15
-#define SCREEN_WIDTH 1920
-#define SCREEN_HEIGHT 1080
-
-static btstack_timer_source_t mousing_timer;
-static int mousing_active = 0;
-
 static void mousing_timer_handler(btstack_timer_source_t * ts){
 
     if (con_handle == HCI_CON_HANDLE_INVALID) {
-        mousing_active = 0;
+        INFO_LOG("Disabling mouse\n");
+        mouse_active = 0;
         return;
     }
 
@@ -261,38 +279,49 @@ static void mousing_timer_handler(btstack_timer_source_t * ts){
     abs_x += dx;
     abs_y += dy;
 
-    // trigger send
+    // trigger send. We can call this from here because we are in a btstack callback
     hids_device_request_can_send_now_event(con_handle);
 
     // set next timer
     btstack_run_loop_set_timer(ts, MOUSE_PERIOD_MS);
     btstack_run_loop_add_timer(ts);
 }
 
+static void button_notification_fn(__unused void * arg) {
+    hids_device_request_can_send_now_event(con_handle);
+}
+static btstack_context_callback_registration_t button_notification = { .callback = button_notification_fn };
+
 // IRQ handler for mouse buttons 
 void button_irq_handler(uint gpio, uint32_t events) {
     if (gpio == LEFT_BUTTON_GPIO_NUM) {
-        printf("left click!\n");
+        INFO_LOG("Left click!\n");
         if (!gpio_get(gpio)) {
             buttons = 1;
         } else {
             buttons = 0;
         }
     } else if (gpio == RIGHT_BUTTON_GPIO_NUM) {
-        printf("right click!\n");
+        INFO_LOG("Right click!\n");
         if (!gpio_get(gpio)) {
             buttons = 2;
         } else {
             buttons = 0;
         }
     }
+    // We want to call hids_device_request_can_send_now_event,
+    // but we are in an IRQ and so it's dangerous to call BTStack directly from here.
+    // So we ask BTstack to callback a function from the "main thread"
+    // We could also use an async (when pending) worker using async_when_pending_worker_t,
+    // async_context_add_when_pending_worker and async_context_set_work_pending
+    btstack_run_loop_execute_on_main_thread(&button_notification);
 }
 
 static void hid_embedded_start_mousing(void){
-    if (mousing_active) return;
-    mousing_active = 1;
+    if (mouse_active) return;
+    mouse_active = 1;
 
-    printf("Start mousing..\n");
+    INFO_LOG("Enabling mouse\n");
 
     // set one-shot timer
     mousing_timer.process = &mousing_timer_handler;
@@ -310,30 +339,30 @@ static void packet_handler (uint8_t packet_type, uint16_t channel, uint8_t *pack
     switch (hci_event_packet_get_type(packet)) {
         case HCI_EVENT_DISCONNECTION_COMPLETE:
             con_handle = HCI_CON_HANDLE_INVALID;
-            printf("Disconnected\n");
+            INFO_LOG("Disconnected\n");
             break;
         case SM_EVENT_JUST_WORKS_REQUEST:
-            printf("Just Works requested\n");
+            INFO_LOG("Just Works requested\n");
             sm_just_works_confirm(sm_event_just_works_request_get_handle(packet));
             break;
         case SM_EVENT_NUMERIC_COMPARISON_REQUEST:
-            printf("Confirming numeric comparison: %"PRIu32"\n", sm_event_numeric_comparison_request_get_passkey(packet));
+            INFO_LOG("Confirming numeric comparison: %"PRIu32"\n", sm_event_numeric_comparison_request_get_passkey(packet));
             sm_numeric_comparison_confirm(sm_event_passkey_display_number_get_handle(packet));
             break;
         case SM_EVENT_PASSKEY_DISPLAY_NUMBER:
-            printf("Display Passkey: %"PRIu32"\n", sm_event_passkey_display_number_get_passkey(packet));
+            INFO_LOG("Display Passkey: %"PRIu32"\n", sm_event_passkey_display_number_get_passkey(packet));
             break;
         case L2CAP_EVENT_CONNECTION_PARAMETER_UPDATE_RESPONSE:
-            printf("L2CAP Connection Parameter Update Complete, response: %x\n", l2cap_event_connection_parameter_update_response_get_result(packet));
+            DEBUG_LOG("L2CAP Connection Parameter Update Complete, response: %x\n", l2cap_event_connection_parameter_update_response_get_result(packet));
             break;
         case HCI_EVENT_META_GAP:
             switch (hci_event_gap_meta_get_subevent_code(packet)) {
                 case GAP_SUBEVENT_LE_CONNECTION_COMPLETE:
                     // print connection parameters (without using float operations)
                     conn_interval = gap_subevent_le_connection_complete_get_conn_interval(packet);
-                    printf("LE Connection Complete:\n");
-                    printf("- Connection Interval: %u.%02u ms\n", conn_interval * 125 / 100, 25 * (conn_interval & 3));
-                    printf("- Connection Latency: %u\n", gap_subevent_le_connection_complete_get_conn_latency(packet));
+                    DEBUG_LOG("LE Connection Complete:\n");
+                    DEBUG_LOG("- Connection Interval: %u.%02u ms\n", conn_interval * 125 / 100, 25 * (conn_interval & 3));
+                    DEBUG_LOG("- Connection Latency: %u\n", gap_subevent_le_connection_complete_get_conn_latency(packet));
                     break;
                 default:
                     break;
@@ -344,9 +373,9 @@ static void packet_handler (uint8_t packet_type, uint16_t channel, uint8_t *pack
                 case HCI_SUBEVENT_LE_CONNECTION_UPDATE_COMPLETE:
                     // print connection parameters (without using float operations)
                     conn_interval = hci_subevent_le_connection_update_complete_get_conn_interval(packet);
-                    printf("LE Connection Update:\n");
-                    printf("- Connection Interval: %u.%02u ms\n", conn_interval * 125 / 100, 25 * (conn_interval & 3));
-                    printf("- Connection Latency: %u\n", hci_subevent_le_connection_update_complete_get_conn_latency(packet));
+                    DEBUG_LOG("LE Connection Update:\n");
+                    DEBUG_LOG("- Connection Interval: %u.%02u ms\n", conn_interval * 125 / 100, 25 * (conn_interval & 3));
+                    DEBUG_LOG("- Connection Latency: %u\n", hci_subevent_le_connection_update_complete_get_conn_latency(packet));
                     break;
                 default:
                     break;
@@ -356,28 +385,20 @@ static void packet_handler (uint8_t packet_type, uint16_t channel, uint8_t *pack
             switch (hci_event_hids_meta_get_subevent_code(packet)){
                 case HIDS_SUBEVENT_INPUT_REPORT_ENABLE:
                     con_handle = hids_subevent_input_report_enable_get_con_handle(packet);
-                    printf("Report Characteristic Subscribed %u\n", hids_subevent_input_report_enable_get_enable(packet));
-#ifndef HAVE_BTSTACK_STDIN
+                    DEBUG_LOG("Report Characteristic Subscribed %u\n", hids_subevent_input_report_enable_get_enable(packet));
                     hid_embedded_start_mousing();
-#endif
-                    // request connection param update via L2CAP following Apple Bluetooth Design Guidelines
-                    // gap_request_connection_parameter_update(con_handle, 12, 12, 4, 100);    // 15 ms, 4, 1s
-
-                    // directly update connection params via HCI following Apple Bluetooth Design Guidelines
-                    // gap_update_connection_parameters(con_handle, 12, 12, 4, 100);    // 60-75 ms, 4, 1s
-
                     break;
                 case HIDS_SUBEVENT_BOOT_KEYBOARD_INPUT_REPORT_ENABLE:
                     con_handle = hids_subevent_boot_keyboard_input_report_enable_get_con_handle(packet);
-                    printf("Boot Keyboard Characteristic Subscribed %u\n", hids_subevent_boot_keyboard_input_report_enable_get_enable(packet));
+                    DEBUG_LOG("Boot Keyboard Characteristic Subscribed %u\n", hids_subevent_boot_keyboard_input_report_enable_get_enable(packet));
                     break;
                 case HIDS_SUBEVENT_BOOT_MOUSE_INPUT_REPORT_ENABLE:
                     con_handle = hids_subevent_boot_mouse_input_report_enable_get_con_handle(packet);
-                    printf("Boot Mouse Characteristic Subscribed %u\n", hids_subevent_boot_mouse_input_report_enable_get_enable(packet));
+                    DEBUG_LOG("Boot Mouse Characteristic Subscribed %u\n", hids_subevent_boot_mouse_input_report_enable_get_enable(packet));
                     break;
                 case HIDS_SUBEVENT_PROTOCOL_MODE:
                     protocol_mode = hids_subevent_protocol_mode_get_protocol_mode(packet);
-                    printf("Protocol Mode: %s mode\n", hids_subevent_protocol_mode_get_protocol_mode(packet) ? "Report" : "Boot");
+                    DEBUG_LOG("Protocol Mode: %s mode\n", hids_subevent_protocol_mode_get_protocol_mode(packet) ? "Report" : "Boot");
                     break;
                 case HIDS_SUBEVENT_CAN_SEND_NOW:
                     send_report(buttons, dx, dy);
@@ -395,12 +416,6 @@ static void packet_handler (uint8_t packet_type, uint16_t channel, uint8_t *pack
 int main(void) {
     stdio_init_all();
 
-#if !defined(i2c_default) || !defined(PICO_DEFAULT_I2C_SDA_PIN) || !defined(PICO_DEFAULT_I2C_SCL_PIN)
-    #warning Example requires a board with I2C pins
-    puts("Default I2C pins were not defined");
-    return 1;
-#endif
-
     // Make the I2C pins available to picotool
     bi_decl(bi_2pins_with_func(PICO_DEFAULT_I2C_SDA_PIN, PICO_DEFAULT_I2C_SCL_PIN, GPIO_FUNC_I2C));
 
@@ -440,8 +455,20 @@ int main(void) {
     // turn on!
     hci_power_control(HCI_POWER_ON);
 
-    while (true) {
+    // btstack_run_loop_execute is only required when using the 'polling' method (e.g. using pico_cyw43_arch_poll library).
+    // This example uses the 'threadsafe background` method, where BT work is handled in a low priority IRQ, so it
+    // is fine to call bt_stack_run_loop_execute() but equally you can continue executing user code.
+
+#if 1 // this is only necessary when using polling (which we aren't, but we're showing it is still safe to call in this case)
+    btstack_run_loop_execute();
+#else
+    // this core is free to do it's own stuff except when using 'polling' method (in which case you should use
+    // btstacK_run_loop_ methods to add work to the run loop.
+
+    // this is a forever loop in place of where user code would go.
+    while(true) {
         sleep_ms(1000);
     }
+#endif
     return 0;
 }