add schematic

.gitignore

@@ -1 +1 @@
-/build/**/*
+/*/**/*

README.md

@@ -4,14 +4,20 @@ This project uses a Raspberry Pi Pico W as a Bluetooth Low Energy adapter for
 a wired USB HID input peripheral, allowing it to connect to a host device
 over BLE using HID over GATT Profile.
 
+
 ## Setup
 
+[YouTube Video](https://youtu.be/YuHbTrccshw)
+
 ### Hardware
 
 You will need the following hardware to make the device:
 - Raspberry Pi Pico W
 - USB extension cable
 
+![Wiring schematic](schematic.svg)
+
+
 You will need to cut the USB extension in half and connect the wires from the
 female end to the Raspberry Pi Pico W. The default configuration is to attach
 the USB's green wire to pin 1/GP0 and USB's white wire to pin 2/GP1. You will
@@ -27,6 +33,8 @@ respectively. For the data wires, you can solder them to the two test points
 TP2 and TP3 on the back of the Raspberry Pi Pico. The white cable goes to TP2
 and the green cable to TP3.
 
+![Wiring of USB connectors to Raspberry Pi Pico W](diagram.png)
+
 The individual wires on the USB can be fragile, so hot glue or other strain
 relief is a good idea. 
 

bt_device.c

@@ -26,6 +26,7 @@ static btstack_packet_callback_registration_t l2cap_event_callback_registration;
 static btstack_packet_callback_registration_t sm_event_callback_registration;
 static uint8_t battery = 100;
 hci_con_handle_t con_handle = HCI_CON_HANDLE_INVALID;
+uint16_t conn_interval=1000;
 static uint8_t protocol_mode = 1;
 
 static hids_device_report_t *dev_report_storage;
@@ -45,16 +46,11 @@ const uint8_t adv_data_len = sizeof(adv_data);
 static void bt_hid_setup(void);
 static void packet_handler (uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size);
 
-//extern uint8_t desc_hid_report[];
-//extern uint16_t desc_hid_report_len;
-
 // start BTstack
 void btstack_main(void){
 	bt_hid_setup();
 
 	init_report_buf();
-
-	hci_power_control(HCI_POWER_ON);
 }
 
 static void bt_hid_setup(void) {
@@ -79,7 +75,7 @@ static void bt_hid_setup(void) {
 
 	// setup HID Device service
 	dev_report_storage = (hids_device_report_t *)malloc(sizeof(hids_device_report_t)*NUM_REPORT_IDS);
-	hids_device_init_with_storage(0, get_desc_hid_report(), get_desc_hid_report_len(), NUM_REPORT_IDS, dev_report_storage);
+	hids_device_init_with_storage(0, desc_hid_report, desc_hid_report_len, NUM_REPORT_IDS, dev_report_storage);
 
 	// setup advertisements
 	uint16_t adv_int_min = 0x0030;
@@ -112,48 +108,56 @@ static void packet_handler (uint8_t packet_type, uint16_t channel, uint8_t *pack
 	(void) channel;
 	(void) size;
 
-	uint16_t conn_interval;
 
 	if (packet_type != HCI_EVENT_PACKET) return;
 
 	switch (hci_event_packet_get_type(packet)) {
 		case HCI_EVENT_DISCONNECTION_COMPLETE:
 			con_handle = HCI_CON_HANDLE_INVALID;
-			printf("Disconnected\n");
+			cdc_print_msg("Disconnected\n");
 
-			set_host_state(HOST_STOP_LISTEN);
+			host_state=HOST_STOP_LISTEN;
 			cyw43_arch_gpio_put(CYW43_WL_GPIO_LED_PIN, 0);
 			break;
 		case SM_EVENT_JUST_WORKS_REQUEST:
-			printf("Just Works requested\n");
+			cdc_print_msg("Just Works requested\n");
 			sm_just_works_confirm(sm_event_just_works_request_get_handle(packet));
 			cyw43_arch_gpio_put(CYW43_WL_GPIO_LED_PIN, 0);
 			break;
 		case SM_EVENT_NUMERIC_COMPARISON_REQUEST:
-			printf("Confirming numeric comparison: %"PRIu32"\n", sm_event_numeric_comparison_request_get_passkey(packet));
+			cdc_count = sprintf(cdc_buf, "Confirming numeric comparison: %"PRIu32"\n", sm_event_numeric_comparison_request_get_passkey(packet));
+			cdc_print_str(cdc_buf, cdc_count);
 			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));
+			cdc_count = sprintf(cdc_buf, "Display Passkey: %"PRIu32"\n", sm_event_passkey_display_number_get_passkey(packet));
+			cdc_print_str(cdc_buf, cdc_count);
 			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));
+			cdc_count = sprintf(cdc_buf, "L2CAP Connection Parameter Update Complete, response: %x\n", l2cap_event_connection_parameter_update_response_get_result(packet));
+			cdc_print_str(cdc_buf, cdc_count);
 			break;
 		case HCI_EVENT_LE_META:
 			switch (hci_event_le_meta_get_subevent_code(packet)) {
 				case HCI_SUBEVENT_LE_CONNECTION_COMPLETE:
 					// print connection parameters (without using float operations)
 					conn_interval = hci_subevent_le_connection_complete_get_conn_interval(packet);
-					printf("LE Connection Complete:\n");
+					set_host_poll_interval(conn_interval);
-					printf("- Connection Interval: %u.%02u ms\n", conn_interval * 125 / 100, 25 * (conn_interval & 3));
+					cdc_print_msg("LE Connection Complete:\n");
-					printf("- Connection Latency: %u\n", hci_subevent_le_connection_complete_get_conn_latency(packet));
+					cdc_count = sprintf(cdc_buf, "- Connection Interval: %u.%02u ms\n", conn_interval * 125 / 100, 25 * (conn_interval & 3));
+					cdc_print_str(cdc_buf, cdc_count);
+					cdc_count = sprintf(cdc_buf, "- Connection Latency: %u\n", hci_subevent_le_connection_complete_get_conn_latency(packet));
+					cdc_print_str(cdc_buf, cdc_count);
 					break;
 				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");
+					set_host_poll_interval(conn_interval);
-					printf("- Connection Interval: %u.%02u ms\n", conn_interval * 125 / 100, 25 * (conn_interval & 3));
+					cdc_print_msg("LE Connection Update:\n");
-					printf("- Connection Latency: %u\n", hci_subevent_le_connection_update_complete_get_conn_latency(packet));
+					cdc_count = sprintf(cdc_buf, "- Connection Interval: %u.%02u ms\n", conn_interval * 125 / 100, 25 * (conn_interval & 3));
+					cdc_print_str(cdc_buf, cdc_count);
+					cdc_count = sprintf(cdc_buf, "- Connection Latency: %u\n", hci_subevent_le_connection_update_complete_get_conn_latency(packet));
+					cdc_print_str(cdc_buf, cdc_count);
 					break;
 				default:
 					break;
@@ -163,9 +167,10 @@ 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));
+					cdc_count = sprintf(cdc_buf, "Report Characteristic Subscribed %u\n", hids_subevent_input_report_enable_get_enable(packet));
+					cdc_print_str(cdc_buf, cdc_count);
 
-					set_host_state(HOST_START_LISTEN);
+					host_state=HOST_START_LISTEN;
 					cyw43_arch_gpio_put(CYW43_WL_GPIO_LED_PIN, 1);
 					// 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
@@ -176,10 +181,11 @@ static void packet_handler (uint8_t packet_type, uint16_t channel, uint8_t *pack
 					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");
+					cdc_count = sprintf(cdc_buf, "Protocol Mode: %s mode\n", hids_subevent_protocol_mode_get_protocol_mode(packet) ? "Report" : "Boot");
+					cdc_print_str(cdc_buf, cdc_count);
 					break;
 				case HIDS_SUBEVENT_CAN_SEND_NOW:
-					printf("HIDS_SUBEVENT_CAN_SEND_NOW\n");
+					//cdc_print_msg("HIDS_SUBEVENT_CAN_SEND_NOW\n");
 					send_report();
 					cyw43_arch_gpio_put(CYW43_WL_GPIO_LED_PIN, 1-cyw43_arch_gpio_get(CYW43_WL_GPIO_LED_PIN));
 					break;
@@ -197,9 +203,10 @@ static void packet_handler (uint8_t packet_type, uint16_t channel, uint8_t *pack
 void update_desc_hid_report(void) {
 	hci_power_control(HCI_POWER_OFF);
 
-	uint16_t len = get_desc_hid_report_len();
+	if (desc_hid_report_len>0) {
-	if (len>0) {
+		//cdc_print_msg("Update HID report descriptor: ");
-		hids_device_init_with_storage(0, get_desc_hid_report(), len, NUM_REPORT_IDS, dev_report_storage);
+		//cdc_print_hex(desc_hid_report, desc_hid_report_len);
+		hids_device_init_with_storage(0, desc_hid_report, desc_hid_report_len, NUM_REPORT_IDS, dev_report_storage);
 		hci_power_control(HCI_POWER_ON);
 	}
 }

bt_device.h

@@ -1,6 +1,8 @@
 #ifndef BT_DEVICE_H_
 #define BT_DEVICE_H_
 
+extern uint16_t conn_interval;
+
 void btstack_main(void);
 void update_desc_hid_report(void);
 

btstack_config.h

@@ -86,7 +86,4 @@
 // To get the audio demos working even with HCI dump at 115200, this truncates long ACL packets
 //#define HCI_DUMP_STDOUT_MAX_SIZE_ACL 100
 
-// enable larger HID descriptor
-#define MAX_ATTRIBUTE_VALUE_SIZE 512
-
 #endif // _PICO_BTSTACK_BTSTACK_CONFIG_H

hid_report.c

@@ -11,14 +11,19 @@
 
 #include "usb_device.h"
 #include "usb_host.h"
+#include "bt_device.h"
 
 #include "hid_report.h"
 
+extern hci_con_handle_t con_handle;
+
+uint8_t desc_hid_report[HID_DESCRIPTOR_SIZE];
+uint16_t desc_hid_report_len=0;
+
 static uint8_t buffer_storage[REPORT_BUF_SIZE];
 static btstack_ring_buffer_t report_buf;
 
-static uint8_t desc_hid_report[HID_DESCRIPTOR_SIZE];
+static struct report_data *report;
-static uint16_t desc_hid_report_len=0;
 static struct report_desc *descriptors;
 
 static struct report_desc* report_desc_alloc(void);
@@ -30,8 +35,6 @@ static void report_dict_init(struct report_dict *mapping);
 static void report_dict_free(struct report_dict *mapping, struct report_desc *descriptor);
 static struct report_dict* find_mapping(uint8_t dev_addr, uint8_t instance, uint8_t report_id);
 
-extern hci_con_handle_t con_handle;
-
 // start listening to HID input reports on all mounted devices
 bool request_hid_reports_all(void) {
 	// send request to receive reports on all mounted devices
@@ -39,15 +42,18 @@ bool request_hid_reports_all(void) {
 	for (current=descriptors; current != NULL; current=current->next) {
 		if (! current->listening) {
 			if(request_hid_report(current->dev_addr, current->instance)) {
-				char tempbuf[40];
+				cdc_count = sprintf(cdc_buf, "Listening to input reports on [%u:%u]\n", current->dev_addr, current->instance);
-				size_t count = sprintf(tempbuf, "Listening to input reports on [%u:%u]\n", current->dev_addr, current->instance);
+				cdc_print_str(cdc_buf, cdc_count);
-				cdc_print_str(tempbuf, count);
 				current->listening = true;
 			} else {
+				cdc_print_msg("Error listening to input report(s)\n");
+				stop_hid_reports_all();
 				return false;
 			}
 		}
 	}
+
+	host_state = HOST_LISTENING;
 	return true;
 }
 
@@ -58,15 +64,17 @@ bool stop_hid_reports_all(void) {
 	for (current=descriptors; current != NULL; current=current->next) {
 		if (current->listening) {
 			if(stop_hid_report(current->dev_addr, current->instance)) {
-				char tempbuf[40];
+				cdc_count = sprintf(cdc_buf, "Stopping input reports on [%u:%u]\n", current->dev_addr, current->instance);
-				size_t count = sprintf(tempbuf, "Stopping input reports on [%u:%u]\n", current->dev_addr, current->instance);
+				cdc_print_str(cdc_buf, cdc_count);
-				cdc_print_str(tempbuf, count);
 				current->listening = false;
 			} else {
+				cdc_print_msg("Error stopping input report(s)\n");
 				return false;
 			}
 		}
 	}
+
+	host_state = HOST_INACTIVE;
 	return true;
 }
 
@@ -74,49 +82,50 @@ bool stop_hid_reports_all(void) {
 void send_report(){
 	// process queue and send next report
 	if (btstack_ring_buffer_bytes_available(&report_buf)) {
-		uint8_t dev_addr;
-		uint8_t instance;
 		uint8_t len8[2];
-		uint16_t len;
 		uint32_t num_bytes_read;
 
 		// retrieve dev_addr from ring_buffer
-		btstack_ring_buffer_read(&report_buf, &dev_addr, 1, &num_bytes_read);
+		btstack_ring_buffer_read(&report_buf, &report->dev_addr, 1, &num_bytes_read);
 
 		// retrieve instance from ring buffer
-		btstack_ring_buffer_read(&report_buf, &instance, 1, &num_bytes_read);
+		btstack_ring_buffer_read(&report_buf, &report->instance, 1, &num_bytes_read);
 	
 		// retrieve length as two uint8_t and turn into uint16_t
 		btstack_ring_buffer_read(&report_buf, len8, 2, &num_bytes_read);
-		memcpy(&len, len8, 2);
+		memcpy(&report->len, len8, 2);
 
 		// retrieve report from ring buffer
-		uint8_t report[len];
+		btstack_ring_buffer_read(&report_buf, report->report, report->len, &num_bytes_read);
-		btstack_ring_buffer_read(&report_buf, report, len, &num_bytes_read);
 
 		// find report id mapping
-		struct report_dict * mapping = find_mapping(dev_addr, instance, report[0]);
+		struct report_dict * mapping = find_mapping(report->dev_addr, report->instance, report->report[0]);
 	
-		char tempbuf[16];
+		cdc_count=sprintf(cdc_buf, "[%04x](%u)> ", con_handle, mapping->ble_id);
-		size_t count=sprintf(tempbuf, "[%04x](%u) ", con_handle, mapping->ble_id);
+		cdc_print_str(cdc_buf, cdc_count);
-		cdc_print_str(tempbuf, count);
 
 		// send hid report to ble interface
 		if (mapping != NULL) {
 			if (mapping->report_id==0) {
-				hids_device_send_input_report_for_id(con_handle, mapping->ble_id, report, len);
+				hids_device_send_input_report_for_id(con_handle, mapping->ble_id, report->report, report->len);
-				cdc_print_hex(report, len);
+				cdc_print_hex(report->report, report->len);
 			} else {
 				// replace report ID in original report before sending
-				hids_device_send_input_report_for_id(con_handle, mapping->ble_id, &report[1], len-1);
+				hids_device_send_input_report_for_id(con_handle, mapping->ble_id, &report->report[1], report->len-1);
-				cdc_print_hex(&report[1], len-1);
+				cdc_print_hex(&report->report[1], report->len-1);
 			}
 		}
 		
-		// request send of next report
+		// set host to poll USB
+		if (host_state == HOST_WAIT_POLL) {
+			host_state = HOST_POLL;
+		}
+		// request sending of next report
+		if (btstack_ring_buffer_bytes_available(&report_buf)) {
 			hids_device_request_can_send_now_event(con_handle);
 		}
 	}
+}
 
 // add report to the BTstack ring buffer for sending
 void queue_report(uint8_t dev_addr, uint8_t instance, uint8_t const* report, uint16_t len) {
@@ -125,7 +134,7 @@ void queue_report(uint8_t dev_addr, uint8_t instance, uint8_t const* report, uin
 		uint8_t len8[2];
 		memcpy(len8, &len, 2);
 
-		if (btstack_ring_buffer_bytes_free(&report_buf) >= len+4) {
+		if (btstack_ring_buffer_bytes_free(&report_buf) >= len+5) {
 			// put instance, length, and report into ring buffer if space available
 			btstack_ring_buffer_write(&report_buf, &dev_addr, 1);
 			btstack_ring_buffer_write(&report_buf, &instance, 1);
@@ -136,11 +145,17 @@ void queue_report(uint8_t dev_addr, uint8_t instance, uint8_t const* report, uin
 		// request send on BLE HID interface
 		hids_device_request_can_send_now_event(con_handle);
 	}
+
+	// HID report on device has not been requested, flag so it can be polled
+	struct report_desc * descriptor;
+	descriptor = report_desc_find(dev_addr, instance);
+	descriptor->listening = false;
 }
 
 // allocate memory for HID report ring buffer
 void init_report_buf(void) {
 	btstack_ring_buffer_init(&report_buf, buffer_storage, sizeof(buffer_storage));
+	report = REPORT_DATA_ALLOC();
 }
 
 // allocate memory for USB interface report descriptor
@@ -358,12 +373,3 @@ static struct report_dict * find_mapping(uint8_t dev_addr, uint8_t instance, uin
 
 	return NULL;
 }
-
-uint16_t get_desc_hid_report_len(void) {
-	return desc_hid_report_len;
-}
-
-
-uint8_t const* get_desc_hid_report(void) {
-	return desc_hid_report;
-}

hid_report.h

@@ -1,6 +1,7 @@
 #ifndef HID_REPORT_H_
 #define HID_REPORT_H_
 
+#define REPORT_MAX_SIZE		64
 #define NUM_REPORT_IDS		16
 #define REPORT_BUF_SIZE		256
 #define DESCRIPTOR_BUF_SIZE	256
@@ -22,8 +23,19 @@ struct report_dict {
 	struct report_dict *next;
 };
 
+struct report_data {
+	uint8_t dev_addr;
+	uint8_t instance;
+	uint8_t report[REPORT_MAX_SIZE];
+	uint16_t len;
+};
+
 #define REPORT_DESC_ALLOC() (struct report_desc *)malloc(sizeof(struct report_desc))
 #define REPORT_DICT_ALLOC() (struct report_dict *)malloc(sizeof(struct report_dict))
+#define REPORT_DATA_ALLOC() (struct report_data *)malloc(sizeof(struct report_data))
+
+extern uint8_t desc_hid_report[HID_DESCRIPTOR_SIZE];
+extern uint16_t desc_hid_report_len;
 
 bool request_hid_reports_all(void);
 bool stop_hid_reports_all(void);
@@ -33,7 +45,5 @@ void init_report_buf(void);
 bool add_descriptor(uint8_t dev_addr, uint8_t instance, uint8_t const* desc_report, uint16_t desc_len);
 void remove_instance(uint8_t dev_addr, uint8_t instance);
 bool generate_report_descriptor(void);
-uint16_t get_desc_hid_report_len(void);
-uint8_t const* get_desc_hid_report(void);
 
 #endif

main.c

@@ -12,17 +12,29 @@
 #include "usb_device.h"
 #include "usb_host.h"
 
+static void usb_main(void);
+
 // main loop
 int main(void) {
+	// for PIO USB, we want clock speed to be multiple of 12MHz
+	set_sys_clock_khz(144000, true);
 
-	set_sys_clock_khz(192000, true);
+	// need so BTstack can save pairing information to flash
+	flash_safe_execute_core_init();
 
 	sleep_ms(10);
 
-	// setup BLE on core 1
+	// run BLE on core 1
 	multicore_reset_core1();
 	multicore_launch_core1(btstack_main);
 
+	// run usb on core 0
+	usb_main();
+
+	return 0;
+}
+
+static void usb_main(void) {
 	// init and run usb host
 	usb_host_init();
 
@@ -30,35 +42,18 @@ int main(void) {
 	usb_device_init();
 
 	while (true) {
-		switch ( get_host_state() ) {
+		switch ( host_state ) {
 			case HOST_NEW_DESCRIPTOR:
-				if ( host_ready() ) {
+				host_ready();
-					if(generate_report_descriptor()) {
-						if ( get_desc_hid_report_len() > 0 ) {
-							set_host_state(HOST_MOUNTED);
-							cyw43_arch_gpio_put(CYW43_WL_GPIO_LED_PIN, 1);
-						} else {
-							set_host_state(HOST_INACTIVE);
-						}
-						cdc_print_msg("Updating HID report map\n");
-						update_desc_hid_report();
-					}
-				}
 				break;
 			case HOST_START_LISTEN:
-				if (request_hid_reports_all()) {
+				request_hid_reports_all();
-					set_host_state(HOST_LISTENING);
-				} else {
-					cdc_print_msg("Error listening to input report(s)\n");
-					set_host_state(HOST_INACTIVE);
-				}
 				break;
 			case HOST_STOP_LISTEN:
-				if (stop_hid_reports_all()) {
+				stop_hid_reports_all();
-					set_host_state(HOST_INACTIVE);
+				break;
-				} else {
+			case HOST_POLL:
-					cdc_print_msg("Error stopping input report(s)\n");
+				poll_devices();
-				}
 				break;
 			default:
 				break;
@@ -67,6 +62,4 @@ int main(void) {
 		tud_task(); // tinyusb device task
 		tud_cdc_write_flush();
 	}
-
-	return 0;
 }

tusb_config.h

@@ -88,10 +88,10 @@
 
 // CDC FIFO size of TX and RX
 #define CFG_TUD_CDC_RX_BUFSIZE   32
-#define CFG_TUD_CDC_TX_BUFSIZE   64
+#define CFG_TUD_CDC_TX_BUFSIZE   128
 
 // CDC Endpoint transfer buffer size, more is faster
-#define CFG_TUD_CDC_EP_BUFSIZE   64
+#define CFG_TUD_CDC_EP_BUFSIZE   128
 
 //--------------------------------------------------------------------
 // HOST CONFIGURATION
@@ -121,8 +121,8 @@
 #define CFG_TUH_DEVICE_MAX          (CFG_TUH_HUB*3+1) // hub typically has 4 ports
 
 #define CFG_TUH_HID					(3*CFG_TUH_DEVICE_MAX+1)
-#define CFG_TUH_HID_EPIN_BUFSIZE	64
+#define CFG_TUH_HID_EPIN_BUFSIZE	128
-#define CFG_TUH_HID_EPOUT_BUFSIZE   64
+#define CFG_TUH_HID_EPOUT_BUFSIZE   128
 
 #ifdef __cplusplus
  }

usb_descriptors.c

@@ -100,6 +100,7 @@ char const* string_desc_arr [] =
 	"Raspberry Pi",					// 1: Manufacturer
 	"Pico BLE HID",					// 2: Product
 	NULL,							// 3: Serials, should use chip ID
+	"Pico BLE HID CDC",				// 4: Product
 };
 
 static uint16_t _desc_str[32+1];

usb_device.c

@@ -9,6 +9,10 @@
 
 #include "usb_device.h"
 
+char cdc_buf[64];
+uint16_t cdc_len;
+size_t cdc_count;
+
 void usb_device_init(void) {
 	// run TinyUSB device
 	tusb_rhport_init_t dev_init = {
@@ -44,21 +48,23 @@ uint16_t tud_hid_get_report_cb(uint8_t instance, uint8_t report_id, hid_report_t
 
 // print message to CDC in raw hex
 void cdc_print_hex(uint8_t const* msg, uint16_t msg_len) {
-	char tempbuf[8];
+	(void) msg;
-	size_t count;
+	(void) msg_len;
 	for (int i=0; i<msg_len; i++) {
-		count=sprintf(tempbuf, "%02X ", msg[i]);
+		cdc_count=sprintf(cdc_buf, "%02X ", msg[i]);
-		tud_cdc_write(tempbuf, count);
+		tud_cdc_write(cdc_buf, cdc_count);
 	}
 	tud_cdc_write_str("\n");
 }
 
 // print text message to CDC
 void cdc_print_str(char const* msg, uint16_t msg_len) {
+	(void) msg;
+	(void) msg_len;
 	tud_cdc_write(msg, msg_len);
 }
 
 void cdc_print_msg(char const* msg) {
-	uint16_t msg_len = strlen(msg);
+	cdc_len = strlen(msg);
-	cdc_print_str(msg, msg_len);
+	cdc_print_str(msg, cdc_len);
 }

usb_device.h

@@ -1,5 +1,9 @@
-#ifndef MAIN_DEVICE_H_
+#ifndef USB_DEVICE_H_
-#define MAIN_DEVICE_H_
+#define USB_DEVICE_H_
+
+extern char cdc_buf[64];
+extern uint16_t cdc_len;
+extern size_t cdc_count;
 
 void usb_device_init(void);
 void cdc_print_hex(uint8_t const* msg, uint16_t msg_len);

usb_host.c

@@ -11,11 +11,14 @@
 
 #include "hid_report.h"
 #include "usb_device.h"
+#include "bt_device.h"
 
 #include "usb_host.h"
 
-static host_state_t host_state;
+host_state_t host_state;
 static absolute_time_t request_time;
+static absolute_time_t last_report;
+static uint16_t host_poll_interval=HOST_POLL_INTERVAL;
 
 // initialize usb host
 void usb_host_init(void) {
@@ -32,7 +35,7 @@ void usb_host_init(void) {
 	tuh_hid_set_default_protocol(HID_PROTOCOL_REPORT);
 	tusb_init(BOARD_TUH_RHPORT, &host_init);
 
-	set_host_state(HOST_INACTIVE);
+	host_state=HOST_INACTIVE;
 }
 
 
@@ -44,16 +47,12 @@ void tuh_hid_mount_cb(uint8_t dev_addr, uint8_t instance, uint8_t const* desc_re
 	uint8_t const itf_protocol = tuh_hid_interface_protocol(dev_addr, instance);
 
 	/// send device vid:pid information to CDC for debugging
-	char tempbuf[CFG_TUD_CDC_TX_BUFSIZE];
+	cdc_count = sprintf(cdc_buf, "Mount: [%04x:%04x][%u:%u] Protocol = %u\n", vid, pid, dev_addr, instance, itf_protocol);
-	size_t count = sprintf(tempbuf, "Mount: [%04x:%04x][%u:%u] Protocol = %u\n", vid, pid, dev_addr, instance, itf_protocol);
+	cdc_print_str(cdc_buf, cdc_count);
-	cdc_print_str(tempbuf, count);
-
-	// print descriptor
-	//cdc_print_hex(desc_report, desc_len);
 
 	// add to HID report descriptor
 	if ( add_descriptor(dev_addr, instance, desc_report, desc_len)) {
-		set_host_state(HOST_NEW_DESCRIPTOR);
+		host_state=HOST_NEW_DESCRIPTOR;
 		request_time=get_absolute_time();
 		cyw43_arch_gpio_put(CYW43_WL_GPIO_LED_PIN, 0);
 	}
@@ -63,58 +62,75 @@ void tuh_hid_mount_cb(uint8_t dev_addr, uint8_t instance, uint8_t const* desc_re
 void tuh_hid_umount_cb(uint8_t dev_addr, uint8_t instance)
 {
 	// send device address:instance to CDC for debugging
-	char tempbuf[CFG_TUD_CDC_TX_BUFSIZE];
+	cdc_count = sprintf(cdc_buf, "Unmount: [%u:%u]\n", dev_addr, instance);
-	size_t count = sprintf(tempbuf, "Unmount: [%u:%u]\n", dev_addr, instance);
+	cdc_print_str(cdc_buf, cdc_count);
-	cdc_print_str(tempbuf, count);
 
 	if (stop_hid_report(dev_addr, instance)) {
 		cdc_print_msg("Successfully stopped receiving reports\n");
 	}
 
 	remove_instance(dev_addr, instance);
-	set_host_state(HOST_NEW_DESCRIPTOR);
+	host_state=HOST_NEW_DESCRIPTOR;
 	request_time=get_absolute_time();
 }
 
 // Invoked when received report from device via interrupt endpoint
 void tuh_hid_report_received_cb(uint8_t dev_addr, uint8_t instance, uint8_t const* report, uint16_t len)
 {
-	char tempbuf[32];
+	cdc_count = sprintf(cdc_buf, "[%u:%u](%u)< ", dev_addr, instance, len);
-	size_t count = sprintf(tempbuf, "[%04x:%04x](%u) ", dev_addr, instance, len);
+	cdc_print_str(cdc_buf,cdc_count);
-	cdc_print_str(tempbuf,count);
 	cdc_print_hex(report, len);
 
+	last_report = get_absolute_time();
+	host_state = HOST_WAIT_POLL;
 	queue_report(dev_addr, instance, report, len);
 
 	// continue to request to receive report
-	if ( !tuh_hid_receive_report(dev_addr, instance) )
+	/*if ( !tuh_hid_receive_report(dev_addr, instance) )
 	{
 		cdc_print_msg("Error: cannot request report\r\n");
+	}*/
+}
+
+// get host ready by updating descriptors
+void host_ready(void) {
+	if (absolute_time_diff_us(request_time, get_absolute_time()) >= 1000000){
+		if(generate_report_descriptor()) {
+			if ( desc_hid_report_len > 0 ) {
+				host_state=HOST_MOUNTED;
+				cyw43_arch_gpio_put(CYW43_WL_GPIO_LED_PIN, 1);
+			} else {
+				host_state=HOST_INACTIVE;
+			}
+			cdc_print_msg("Updating HID report map\n");
+			update_desc_hid_report();
+		}
 	}
 }
 
-// set the state of the host
+// set devices to listening once polling interval has passed
-void set_host_state(host_state_t new_host_state) {
+void poll_devices(void) {
-	host_state = new_host_state;
+	if (absolute_time_diff_us(last_report, get_absolute_time()) >= host_poll_interval) {
+		request_hid_reports_all();
+		host_state = HOST_LISTENING;
+	}
 }
 
-// get the current state of the host
+// set the USB host polling interval based on the BT connection interval
-host_state_t get_host_state(void) {
+void set_host_poll_interval(uint16_t bt_conn_interval) {
-	return host_state;
+	if (bt_conn_interval*1250 > HOST_POLL_INTERVAL) {
+		host_poll_interval = bt_conn_interval*1250;
+	} else {
+		host_poll_interval = HOST_POLL_INTERVAL;
 	}
-
-// indicate whether host is ready for updating descriptors
-bool host_ready(void) {
-	return (absolute_time_diff_us(request_time, get_absolute_time()) > 1000000);
 }
 
 // request HID input reports on specified device address and instance
 bool request_hid_report(uint8_t dev_addr, uint8_t instance) {
 	// request to receive reports HID devices
 	if ( !tuh_hid_receive_report(dev_addr, instance) ) {
-		char tempbuf[CFG_TUD_CDC_TX_BUFSIZE];
+		cdc_count = sprintf(cdc_buf, "Error: cannot request report on [%u:%u]\n", dev_addr, instance);
-		size_t count = sprintf(tempbuf, "Error: cannot request report on [%u:%u]\n", dev_addr, instance);
+		cdc_print_str(cdc_buf, cdc_count);
-		cdc_print_str(tempbuf, count);
 		return false;
 	}
 	return true;

usb_host.h

@@ -1,5 +1,7 @@
-#ifndef MAIN_HOST_H_
+#ifndef USB_HOST_H_
-#define MAIN_HOST_H_
+#define USB_HOST_H_
+
+#define HOST_POLL_INTERVAL	8000
 
 typedef enum {
 	HOST_INACTIVE=0,
@@ -7,14 +9,17 @@ typedef enum {
 	HOST_MOUNTED,
 	HOST_START_LISTEN,
 	HOST_LISTENING,
+	HOST_WAIT_POLL,
+	HOST_POLL,
 	HOST_STOP_LISTEN,
 } host_state_t;
 
+extern host_state_t host_state;
 
 void usb_host_init(void);
-void set_host_state(host_state_t new_host_state);
+void host_ready(void);
-host_state_t get_host_state(void);
+void poll_devices(void);
-bool host_ready(void);
+void set_host_poll_interval(uint16_t bt_conn_interval);
 bool request_hid_report(uint8_t dev_addr, uint8_t instance);
 bool stop_hid_report(uint8_t dev_addr, uint8_t instance);