hid_keyboard_demo.c

/*
 * Copyright (C) 2014 BlueKitchen GmbH
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the copyright holders nor the names of
 *    contributors may be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 * 4. Any redistribution, use, or modification is done solely for
 *    personal benefit and not for any commercial purpose or for
 *    monetary gain.
 *
 * THIS SOFTWARE IS PROVIDED BY BLUEKITCHEN GMBH AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL BLUEKITCHEN
 * GMBH OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
 * THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * Please inquire about commercial licensing options at
 * contact@bluekitchen-gmbh.com
 *
 */

#define BTSTACK_FILE__ "hid_keyboard_demo.c"

// *****************************************************************************
/* EXAMPLE_START(hid_keyboard_demo): HID Keyboard Classic
 *
 * @text This HID Device example demonstrates how to implement
 * an HID keyboard. Without a HAVE_BTSTACK_STDIN, a fixed demo text is sent
 * If HAVE_BTSTACK_STDIN is defined, you can type from the terminal
 */
// *****************************************************************************

#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <inttypes.h>

#include "btstack.h"

#ifdef HAVE_BTSTACK_STDIN
#include "btstack_stdin.h"
#endif

// to enable demo text on POSIX systems
// #undef HAVE_BTSTACK_STDIN

// timing of keypresses
#define TYPING_KEYDOWN_MS 20
#define TYPING_DELAY_MS 20

// When not set to 0xffff, sniff and sniff subrating are enabled
static uint16_t host_max_latency = 1600;
static uint16_t host_min_timeout = 3200;

#define REPORT_ID 0x01

// close to USB HID Specification 1.1, Appendix B.1
const uint8_t hid_descriptor_keyboard[] = {

    0x05, 0x01, // Usage Page (Generic Desktop)
    0x09, 0x06, // Usage (Keyboard)
    0xa1, 0x01, // Collection (Application)

    // Report ID

    0x85, REPORT_ID, // Report ID

    // Modifier byte (input)

    0x75, 0x01, //   Report Size (1)
    0x95, 0x08, //   Report Count (8)
    0x05, 0x07, //   Usage Page (Key codes)
    0x19, 0xe0, //   Usage Minimum (Keyboard LeftControl)
    0x29, 0xe7, //   Usage Maximum (Keyboard Right GUI)
    0x15, 0x00, //   Logical Minimum (0)
    0x25, 0x01, //   Logical Maximum (1)
    0x81, 0x02, //   Input (Data, Variable, Absolute)

    // Reserved byte (input)

    0x75, 0x01, //   Report Size (1)
    0x95, 0x08, //   Report Count (8)
    0x81, 0x03, //   Input (Constant, Variable, Absolute)

    // LED report + padding (output)

    0x95, 0x05, //   Report Count (5)
    0x75, 0x01, //   Report Size (1)
    0x05, 0x08, //   Usage Page (LEDs)
    0x19, 0x01, //   Usage Minimum (Num Lock)
    0x29, 0x05, //   Usage Maximum (Kana)
    0x91, 0x02, //   Output (Data, Variable, Absolute)

    0x95, 0x01, //   Report Count (1)
    0x75, 0x03, //   Report Size (3)
    0x91, 0x03, //   Output (Constant, Variable, Absolute)

    // Keycodes (input)

    0x95, 0x06, //   Report Count (6)
    0x75, 0x08, //   Report Size (8)
    0x15, 0x00, //   Logical Minimum (0)
    0x25, 0xff, //   Logical Maximum (1)
    0x05, 0x07, //   Usage Page (Key codes)
    0x19, 0x00, //   Usage Minimum (Reserved (no event indicated))
    0x29, 0xff, //   Usage Maximum (Reserved)
    0x81, 0x00, //   Input (Data, Array)

    0xc0, // End collection
};

//
#define CHAR_ILLEGAL 0xff
#define CHAR_RETURN '\n'
#define CHAR_ESCAPE 27
#define CHAR_TAB '\t'
#define CHAR_BACKSPACE 0x7f

// Simplified US Keyboard with Shift modifier

/**
 * English (US)
 */
static const uint8_t keytable_us_none[] = {
    CHAR_ILLEGAL, CHAR_ILLEGAL, CHAR_ILLEGAL, CHAR_ILLEGAL,           /*   0-3 */
    'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j',                 /*  4-13 */
    'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't',                 /* 14-23 */
    'u', 'v', 'w', 'x', 'y', 'z',                                     /* 24-29 */
    '1', '2', '3', '4', '5', '6', '7', '8', '9', '0',                 /* 30-39 */
    CHAR_RETURN, CHAR_ESCAPE, CHAR_BACKSPACE, CHAR_TAB, ' ',          /* 40-44 */
    '-', '=', '[', ']', '\\', CHAR_ILLEGAL, ';', '\'', 0x60, ',',     /* 45-54 */
    '.', '/', CHAR_ILLEGAL, CHAR_ILLEGAL, CHAR_ILLEGAL, CHAR_ILLEGAL, /* 55-60 */
    CHAR_ILLEGAL, CHAR_ILLEGAL, CHAR_ILLEGAL, CHAR_ILLEGAL,           /* 61-64 */
    CHAR_ILLEGAL, CHAR_ILLEGAL, CHAR_ILLEGAL, CHAR_ILLEGAL,           /* 65-68 */
    CHAR_ILLEGAL, CHAR_ILLEGAL, CHAR_ILLEGAL, CHAR_ILLEGAL,           /* 69-72 */
    CHAR_ILLEGAL, CHAR_ILLEGAL, CHAR_ILLEGAL, CHAR_ILLEGAL,           /* 73-76 */
    CHAR_ILLEGAL, CHAR_ILLEGAL, CHAR_ILLEGAL, CHAR_ILLEGAL,           /* 77-80 */
    CHAR_ILLEGAL, CHAR_ILLEGAL, CHAR_ILLEGAL, CHAR_ILLEGAL,           /* 81-84 */
    '*', '-', '+', '\n', '1', '2', '3', '4', '5',                     /* 85-97 */
    '6', '7', '8', '9', '0', '.', 0xa7,                               /* 97-100 */
};

static const uint8_t keytable_us_shift[] = {
    CHAR_ILLEGAL, CHAR_ILLEGAL, CHAR_ILLEGAL, CHAR_ILLEGAL,           /*  0-3  */
    'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J',                 /*  4-13 */
    'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T',                 /* 14-23 */
    'U', 'V', 'W', 'X', 'Y', 'Z',                                     /* 24-29 */
    '!', '@', '#', '$', '%', '^', '&', '*', '(', ')',                 /* 30-39 */
    CHAR_RETURN, CHAR_ESCAPE, CHAR_BACKSPACE, CHAR_TAB, ' ',          /* 40-44 */
    '_', '+', '{', '}', '|', CHAR_ILLEGAL, ':', '"', 0x7E, '<',       /* 45-54 */
    '>', '?', CHAR_ILLEGAL, CHAR_ILLEGAL, CHAR_ILLEGAL, CHAR_ILLEGAL, /* 55-60 */
    CHAR_ILLEGAL, CHAR_ILLEGAL, CHAR_ILLEGAL, CHAR_ILLEGAL,           /* 61-64 */
    CHAR_ILLEGAL, CHAR_ILLEGAL, CHAR_ILLEGAL, CHAR_ILLEGAL,           /* 65-68 */
    CHAR_ILLEGAL, CHAR_ILLEGAL, CHAR_ILLEGAL, CHAR_ILLEGAL,           /* 69-72 */
    CHAR_ILLEGAL, CHAR_ILLEGAL, CHAR_ILLEGAL, CHAR_ILLEGAL,           /* 73-76 */
    CHAR_ILLEGAL, CHAR_ILLEGAL, CHAR_ILLEGAL, CHAR_ILLEGAL,           /* 77-80 */
    CHAR_ILLEGAL, CHAR_ILLEGAL, CHAR_ILLEGAL, CHAR_ILLEGAL,           /* 81-84 */
    '*', '-', '+', '\n', '1', '2', '3', '4', '5',                     /* 85-97 */
    '6', '7', '8', '9', '0', '.', 0xb1,                               /* 97-100 */
};

// STATE

static uint8_t hid_service_buffer[300];
static uint8_t device_id_sdp_service_buffer[100];
static const char hid_device_name[] = "BTstack HID Keyboard";
static btstack_packet_callback_registration_t hci_event_callback_registration;
static uint16_t hid_cid;
static uint8_t hid_boot_device = 0;

// HID Report sending
static uint8_t send_buffer_storage[16];
static btstack_ring_buffer_t send_buffer;
static btstack_timer_source_t send_timer;
static uint8_t send_modifier;
static uint8_t send_keycode;
static bool send_active;

#ifdef HAVE_BTSTACK_STDIN
static bd_addr_t device_addr;
static const char *device_addr_string = "BC:EC:5D:E6:15:03";
#endif

static enum {
    APP_BOOTING,
    APP_NOT_CONNECTED,
    APP_CONNECTING,
    APP_CONNECTED
} app_state = APP_BOOTING;

// HID Keyboard lookup
static bool lookup_keycode(uint8_t character, const uint8_t *table, int size, uint8_t *keycode)
{
    int i;
    for (i = 0; i < size; i++)
    {
        if (table[i] != character)
            continue;
        *keycode = i;
        return true;
    }
    return false;
}

static bool keycode_and_modifer_us_for_character(uint8_t character, uint8_t *keycode, uint8_t *modifier)
{
    bool found;
    found = lookup_keycode(character, keytable_us_none, sizeof(keytable_us_none), keycode);
    if (found)
    {
        *modifier = 0; // none
        return true;
    }
    found = lookup_keycode(character, keytable_us_shift, sizeof(keytable_us_shift), keycode);
    if (found)
    {
        *modifier = 2; // shift
        return true;
    }
    return false;
}

static void send_report(int modifier, int keycode)
{
    uint8_t report[] = {0xa1, REPORT_ID, modifier, 0, keycode, 0, 0, 0, 0, 0};
    hid_device_send_interrupt_message(hid_cid, &report[0], sizeof(report));
}

static void trigger_key_up(btstack_timer_source_t *ts)
{
    UNUSED(ts);
    hid_device_request_can_send_now_event(hid_cid);
}

static void send_next(btstack_timer_source_t *ts)
{
    // get next key from buffer
    uint8_t character;
    uint32_t num_bytes_read = 0;
    btstack_ring_buffer_read(&send_buffer, &character, 1, &num_bytes_read);
    if (num_bytes_read == 0)
    {
        // buffer empty, nothing to send
        send_active = false;
    }
    else
    {
        send_active = true;
        // lookup keycode and modifier using US layout
        bool found = keycode_and_modifer_us_for_character(character, &send_keycode, &send_modifier);
        if (found)
        {
            // request can send now
            hid_device_request_can_send_now_event(hid_cid);
        }
        else
        {
            // restart timer for next character
            btstack_run_loop_set_timer(ts, TYPING_DELAY_MS);
            btstack_run_loop_add_timer(ts);
        }
    }
}

static void queue_character(char character)
{
    btstack_ring_buffer_write(&send_buffer, (uint8_t *)&character, 1);
    if (send_active == false)
    {
        send_next(&send_timer);
    }
}

// Demo Application

#ifdef HAVE_BTSTACK_STDIN

// On systems with STDIN, we can directly type on the console

static void stdin_process(char character)
{
    switch (app_state)
    {
    case APP_BOOTING:
    case APP_CONNECTING:
        // ignore
        break;
    case APP_CONNECTED:
        // add char to send buffer
        queue_character(character);
        break;
    case APP_NOT_CONNECTED:
        printf("Connecting to %s...\n", bd_addr_to_str(device_addr));
        hid_device_connect(device_addr, &hid_cid);
        break;
    default:
        btstack_assert(false);
        break;
    }
}
#else

// On embedded systems, send constant demo text

#define TYPING_DEMO_PERIOD_MS 100

static const char *demo_text = "\n\nHello World!\n\nThis is the BTstack HID Keyboard Demo running on an Embedded Device.\n\n";
static int demo_pos;
static btstack_timer_source_t demo_text_timer;

static void demo_text_timer_handler(btstack_timer_source_t *ts)
{
    UNUSED(ts);

    // queue character
    uint8_t character = demo_text[demo_pos++];
    if (demo_text[demo_pos] == 0)
    {
        demo_pos = 0;
    }
    queue_character(character);

    // set timer for next character
    btstack_run_loop_set_timer_handler(&demo_text_timer, demo_text_timer_handler);
    btstack_run_loop_set_timer(&demo_text_timer, TYPING_DEMO_PERIOD_MS);
    btstack_run_loop_add_timer(&demo_text_timer);
}

#endif

static void packet_handler(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t packet_size)
{
    UNUSED(channel);
    UNUSED(packet_size);
    uint8_t status;
    switch (packet_type)
    {
    case HCI_EVENT_PACKET:
        switch (hci_event_packet_get_type(packet))
        {
        case BTSTACK_EVENT_STATE:
            if (btstack_event_state_get_state(packet) != HCI_STATE_WORKING)
                return;
            app_state = APP_NOT_CONNECTED;
            break;

        case HCI_EVENT_USER_CONFIRMATION_REQUEST:
            // ssp: inform about user confirmation request
            log_info("SSP User Confirmation Request with numeric value '%06" PRIu32 "'\n", hci_event_user_confirmation_request_get_numeric_value(packet));
            log_info("SSP User Confirmation Auto accept\n");
            break;

        case HCI_EVENT_HID_META:
            switch (hci_event_hid_meta_get_subevent_code(packet))
            {
            case HID_SUBEVENT_CONNECTION_OPENED:
                status = hid_subevent_connection_opened_get_status(packet);
                if (status != ERROR_CODE_SUCCESS)
                {
                    // outgoing connection failed
                    printf("Connection failed, status 0x%x\n", status);
                    app_state = APP_NOT_CONNECTED;
                    hid_cid = 0;
                    return;
                }
                app_state = APP_CONNECTED;
                hid_cid = hid_subevent_connection_opened_get_hid_cid(packet);
                printf("HID Connected, please start typing...\n");

                break;
            case HID_SUBEVENT_CONNECTION_CLOSED:
                btstack_run_loop_remove_timer(&send_timer);
                printf("HID Disconnected\n");
                app_state = APP_NOT_CONNECTED;
                hid_cid = 0;
                break;
            case HID_SUBEVENT_CAN_SEND_NOW:
                if (send_keycode)
                {
                    send_report(send_modifier, send_keycode);
                    // schedule key up
                    send_keycode = 0;
                    send_modifier = 0;
                    btstack_run_loop_set_timer_handler(&send_timer, trigger_key_up);
                    btstack_run_loop_set_timer(&send_timer, TYPING_KEYDOWN_MS);
                }
                else
                {
                    send_report(0, 0);
                    // schedule next key down
                    btstack_run_loop_set_timer_handler(&send_timer, send_next);
                    btstack_run_loop_set_timer(&send_timer, TYPING_DELAY_MS);
                }
                btstack_run_loop_add_timer(&send_timer);
                break;
            default:
                break;
            }
            break;
        default:
            break;
        }
        break;
    default:
        break;
    }
}

/* @section Main Application Setup
 *
 * @text Listing MainConfiguration shows main application code.
 * To run a HID Device service you need to initialize the SDP, and to create and register HID Device record with it.
 * At the end the Bluetooth stack is started.
 */

/* LISTING_START(MainConfiguration): Setup HID Device */

int btstack_main(int argc, const char *argv[]);
int btstack_main(int argc, const char *argv[])
{
    (void)argc;
    (void)argv;

    // allow to get found by inquiry
    gap_discoverable_control(1);
    // use Limited Discoverable Mode; Peripheral; Keyboard as CoD
    gap_set_class_of_device(0x2540);
    // set local name to be identified - zeroes will be replaced by actual BD ADDR
    gap_set_local_name("HID Keyboard Demo 00:00:00:00:00:00");
    // allow for role switch in general and sniff mode
    gap_set_default_link_policy_settings(LM_LINK_POLICY_ENABLE_ROLE_SWITCH | LM_LINK_POLICY_ENABLE_SNIFF_MODE);
    // allow for role switch on outgoing connections - this allow HID Host to become master when we re-connect to it
    gap_set_allow_role_switch(true);

    // L2CAP
    l2cap_init();

#ifdef ENABLE_BLE
    // Initialize LE Security Manager. Needed for cross-transport key derivation
    sm_init();
#endif

    // SDP Server
    sdp_init();
    memset(hid_service_buffer, 0, sizeof(hid_service_buffer));

    uint8_t hid_virtual_cable = 0;
    uint8_t hid_remote_wake = 1;
    uint8_t hid_reconnect_initiate = 1;
    uint8_t hid_normally_connectable = 1;

    hid_sdp_record_t hid_params = {
        // hid sevice subclass 2540 Keyboard, hid counntry code 33 US
        0x2540, 33,
        hid_virtual_cable, hid_remote_wake,
        hid_reconnect_initiate, hid_normally_connectable,
        hid_boot_device,
        host_max_latency, host_min_timeout,
        3200,
        hid_descriptor_keyboard,
        sizeof(hid_descriptor_keyboard),
        hid_device_name};

    hid_create_sdp_record(hid_service_buffer, 0x10001, &hid_params);

    printf("HID service record size: %u\n", de_get_len(hid_service_buffer));
    sdp_register_service(hid_service_buffer);

    // See https://www.bluetooth.com/specifications/assigned-numbers/company-identifiers if you don't have a USB Vendor ID and need a Bluetooth Vendor ID
    // device info: BlueKitchen GmbH, product 1, version 1
    device_id_create_sdp_record(device_id_sdp_service_buffer, 0x10003, DEVICE_ID_VENDOR_ID_SOURCE_BLUETOOTH, BLUETOOTH_COMPANY_ID_BLUEKITCHEN_GMBH, 1, 1);
    printf("Device ID SDP service record size: %u\n", de_get_len((uint8_t *)device_id_sdp_service_buffer));
    sdp_register_service(device_id_sdp_service_buffer);

    // HID Device
    hid_device_init(hid_boot_device, sizeof(hid_descriptor_keyboard), hid_descriptor_keyboard);

    // register for HCI events
    hci_event_callback_registration.callback = &packet_handler;
    hci_add_event_handler(&hci_event_callback_registration);

    // register for HID events
    hid_device_register_packet_handler(&packet_handler);

#ifdef HAVE_BTSTACK_STDIN
    sscanf_bd_addr(device_addr_string, device_addr);
    btstack_stdin_setup(stdin_process);
#endif

    btstack_ring_buffer_init(&send_buffer, send_buffer_storage, sizeof(send_buffer_storage));

    // turn on!
    hci_power_control(HCI_POWER_ON);
    return 0;
}
/* LISTING_END */
/* EXAMPLE_END */