File content as of revision 5:e90d7b6f83cb:

/*
 *  ------- BLE Central/Client UART function -----------------------------------
 *          communicate with BLE_UART_Server program
 *      --- Tested on Switch Science mbed TY51822r3 ---
 *
 *  Modified by Kenji Arai
 *      http://www.page.sannet.ne.jp/kenjia/index.html
 *      https://os.mbed.com/users/kenjiArai/
 *
 *      Started:  April     8th, 2016
 *      Revised:  June     13th, 2016
 *      Revised:  Feburary 10th, 2018   Not set mac addr but use device name
 *      Revised:  Feburary 11th, 2018   use mbed-os5.7.4 with CircularBuffer
 *
 *  Original program (see original.cpp file):
 *      S130 potential unstability case [closed] by Fabien Comte
 *      https://devzone.nordicsemi.com/question/49705/
 *                              s130-potential-unstability-case/
 *      GitHub Q&A by Fabien COMTE
 *      https://github.com/ARMmbed/ble/issues/69
 *  Reference program:
 *      BLE_Central_test by noboru koshinaka
 *      https://os.mbed.com/users/noboruk/code/BLE_Central_test/
 *  Tested Server Device:
 *      BLE_Uart_Server
 *      https://os.mbed.com/users/kenjiArai/code/BLE_Uart_Server/
 */

//  Include --------------------------------------------------------------------
#include "mbed.h"
#include "BLE.h"
#include "DiscoveredCharacteristic.h"
#include "DiscoveredService.h"
#include "UARTService.h"
#include "CircularBuffer.h"

//  Definition -----------------------------------------------------------------
//#define     USE_MAC           // if you use mac address, please define it

#define     NUM_ONCE            20
#define     BFSIZE              (NUM_ONCE+4)

//#define    USE_DEBUG_MODE
#ifdef USE_DEBUG_MODE
#define DBG(...) { pc.printf(__VA_ARGS__); }
#else
#define DBG(...)
#endif

#define SOFT_DEVICE_FATHER_HANDLE   3

//  Object ---------------------------------------------------------------------
BLE&        ble_uart = BLE::Instance();
DigitalOut  alivenessLED(LED1, 1);
DigitalOut  connectedLED(D10, 0);
Serial      pc(USBTX, USBRX, 115200);
//Serial      pc(P0_3, P0_1, 115200);     // for another board
Ticker      ticker;
CircularBuffer<char, 1536> ser_bf;
Thread      tsk;

//  ROM / Constant data --------------------------------------------------------
#ifdef USE_MAC
#warning "You need to modify below value based on your board."
const Gap::Address_t    mac_board_0   = {0x50, 0x2b, 0xea, 0x14, 0x95, 0xd2};
const Gap::Address_t    mac_board_1   = {0x59, 0x2c, 0xa8, 0x0e, 0xe2, 0xef};
const Gap::Address_t    mac_board_2   = {0x0f, 0x72, 0xbf, 0x43, 0xbc, 0xd0};
const Gap::Address_t    mac_board_3   = {0x83, 0xc9, 0x1a, 0x90, 0xdf, 0xd6};
const Gap::Address_t    mac_board_4   = {0x43, 0xa4, 0x36, 0x11, 0x5b, 0xeb};
#else
const char PEER_NAME[] = "UART_PJL";
#endif

//  RAM ------------------------------------------------------------------------
Gap::Handle_t   connectionHandle        = 0xFFFF;
DiscoveredCharacteristic uartTXCharacteristic;
DiscoveredCharacteristic uartRXCharacteristic;
bool            foundUartRXCharacteristic = false;
bool            connected2server        = false;
bool            connection_tx           = false;
bool            connection_rx           = false;
UARTService *   uartServicePtr          = NULL;
Gap::Address_t  my_mac;
int             my_board_index          = -1;
bool            received_uart_dat       = false;
int8_t          uart_buffer[BFSIZE];
uint8_t         uart_bf_len;
volatile bool   rx_isr_busy             = false;

//  Function prototypes --------------------------------------------------------
//      BLE
void advertisementCallback(const Gap::AdvertisementCallbackParams_t *);
void serviceDiscoveryCallback(const DiscoveredService *);
void characteristicDiscoveryCallback(const DiscoveredCharacteristic *);
void discoveryTerminationCallback(Gap::Handle_t );
void onReceivedDataFromDeviceCallback(const GattHVXCallbackParams *);
void connectionCallback(const Gap::ConnectionCallbackParams_t *);
void disconnectionCallback(const Gap::DisconnectionCallbackParams_t *);
//      Interrupt related
void periodicCallback(void);
void serialRxCallback(void);
//      serial receiving
void pc_ser_rx(void);
void preparation_sending_data(void);
//      Pre-check
bool mac_equals(const Gap::Address_t, const Gap::Address_t);
int  get_board_index(const Gap::Address_t);
void adjust_line(uint8_t *);

//------------------------------------------------------------------------------
//  Control Program
//------------------------------------------------------------------------------
int main(void)
{
    alivenessLED = 0;
    pc.attach(&serialRxCallback, Serial::RxIrq);
    ticker.attach(periodicCallback, 1);
    tsk.start(pc_ser_rx);
    // clear terminal output
    for (int k = 0; k < 3; k++) {
        pc.printf("\r\n");
    }
    // opening message
    pc.printf("UART Communication / Client(Central) side\r\n");
    pc.printf("  need Server module (run BLE_Uart_Server program)\r\n");
    // Mixed role **************************************************************
    ble_uart.init();
    ble_uart.gap().onConnection(connectionCallback);
    ble_uart.gap().onDisconnection(disconnectionCallback);
    // Client(Central) role ****************************************************
    ble_uart.gattClient().onHVX(onReceivedDataFromDeviceCallback);
    ble_uart.gap().setScanParams(500, 450);
    ble_uart.gap().startScan(advertisementCallback);
    while(true) {
        // allow notifications from Server(Peripheral)
        if (foundUartRXCharacteristic &&
                !ble_uart.gattClient().isServiceDiscoveryActive()) {
            // need to do the following only once
            foundUartRXCharacteristic = false;
            uint16_t value = BLE_HVX_NOTIFICATION;
            ble_uart.gattClient().write(
                GattClient::GATT_OP_WRITE_REQ,
                connectionHandle,
                uartRXCharacteristic.getValueHandle() + 1,
                sizeof(uint16_t),
                reinterpret_cast<const uint8_t *>(&value)
            );
        }
        if (received_uart_dat == true) {
            received_uart_dat = false;
            for(int i = 0; i < uart_bf_len; i++) {
                //pc.printf("%c", uart_buffer[i]);
                pc.putc(uart_buffer[i]);
            }
        }
        ble_uart.waitForEvent();
    }
}

void periodicCallback(void)
{
    // Do blinky on alivenessLED to indicate system aliveness
    alivenessLED = !alivenessLED;
    if (connected2server) {
        connectedLED = 1;
    } else {
        connectedLED = 0;
    }
    if (rx_isr_busy == true) {
        rx_isr_busy = false;
    } else {
        tsk.signal_set(0x01);
    }
}

void serialRxCallback()
{
    ser_bf.push(pc.getc());
    rx_isr_busy = true;
    tsk.signal_set(0x01);
}

void pc_ser_rx()
{
    static uint8_t linebf_irq[BFSIZE];
    static volatile uint8_t linebf_irq_len = 0;

    while(true) {
        Thread::signal_wait(0x01);
        if (ser_bf.empty()) {
            if (linebf_irq_len != 0) {
                linebf_irq[linebf_irq_len] = 0;
                adjust_line(linebf_irq);
                linebf_irq_len = 0;
                uartTXCharacteristic.write(NUM_ONCE, linebf_irq);
            }
        }
        while(!ser_bf.empty()) {
            char c;
            ser_bf.pop(c);
            if (c == '\b') {
                linebf_irq_len--;
                pc.putc(c);
                pc.putc(' ');
                pc.putc(c);
            } else if ((c >= ' ') || (c == '\r') || (c == '\n')) {
                bool overflow = false;
                if ((c == '\r') || (c == '\n')) {
                    if (linebf_irq_len == NUM_ONCE - 1) { // remain only 1 buffer
                        overflow = true;
                        linebf_irq[linebf_irq_len++] = '\r';
                        pc.putc('\r');
                    } else {
                        overflow = false;
                        linebf_irq[linebf_irq_len++] = '\r';
                        linebf_irq[linebf_irq_len++] = '\n';
                        pc.printf("\r\n");
                    }
                } else {
                    linebf_irq[linebf_irq_len++] = c;
                    pc.putc(c);
                }
                if (linebf_irq_len >= NUM_ONCE ) {
                    linebf_irq[linebf_irq_len] = 0;
                    uartTXCharacteristic.write(linebf_irq_len, linebf_irq);
                    linebf_irq_len = 0;
                    if (overflow == true) {
                        overflow = false;
                        linebf_irq[linebf_irq_len++] = '\n';
                        pc.putc('\n');
                    }
                }
            }
        }
    }
}

void adjust_line(uint8_t *bf)
{
    uint8_t i, c;

    for (i = 0; i <NUM_ONCE; bf++, i++) {
        c = *bf;
        if (c == 0) {
            break;
        }
    }
    for (; i < NUM_ONCE; bf++, i++) {
        *bf = 0x11;
    }
    *(bf + 1) = 0;
}

void onReceivedDataFromDeviceCallback(const GattHVXCallbackParams *params)
{
    DBG(
        "received HVX callback for handle %u; type %s\r\r\n",
        params->handle,
        (params->type == BLE_HVX_NOTIFICATION) ? "notification" : "indication"
    );
    if (params->type == BLE_HVX_NOTIFICATION) {
        if ((params->handle
                == uartRXCharacteristic.getValueHandle()) && (params->len > 0)) {
            uart_bf_len = params->len;
            strcpy((char *)uart_buffer, (char *)params->data);
            received_uart_dat = true;
        }
    }
}

#ifdef USE_MAC

bool mac_equals(const Gap::Address_t mac_1, const Gap::Address_t mac_2)
{
    DBG("Address: ");
    for (int i = 0; i < 6; i++) {
        DBG("0x%02x ", mac_1[i]);
    }
    DBG("\r\n");
    for (int i = 0; i < 6; i++) {
        if (mac_1[i] != mac_2[i]) {
            DBG("0x%02x != 0x%02x at %d\r\n", mac_1[i], mac_2[i], i);
            return false;
        } else {
            DBG("0x%02x == 0x%02x at %d\r\n", mac_1[i], mac_2[i], i);
        }
    }
    return true;
}

int get_board_index(const Gap::Address_t mac)
{
    if (mac_equals(mac, mac_board_0)) {
        return 0;
    }
    if (mac_equals(mac, mac_board_1)) {
        return 1;
    }
    if (mac_equals(mac, mac_board_2)) {
        return 2;
    }
    if (mac_equals(mac, mac_board_3)) {
        return 3;
    }
    if (mac_equals(mac, mac_board_4)) {
        return 4;
    }
    return -1;
}

// Client(Central) role ********************************************************
void advertisementCallback(const Gap::AdvertisementCallbackParams_t *params)
{
    // connections
    int peer_board_index = get_board_index(params->peerAddr);
    if (peer_board_index != -1) {
        pc.printf("");
        pc.printf(
            "adv peerAddr [%02x %02x %02x %02x %02x %02x]\r\n",
            params->peerAddr[5], params->peerAddr[4], params->peerAddr[3],
            params->peerAddr[2], params->peerAddr[1], params->peerAddr[0]
        );
        pc.printf(
            "rssi=%+4d, isScanResponse %u, AdvertisementType %u\r\n",
            params->rssi, params->isScanResponse, params->type
        );
        ble_uart.gap().connect(
            params->peerAddr, Gap::ADDR_TYPE_RANDOM_STATIC, NULL, NULL);
    }
}

#else

// Client(Central) role ********************************************************
void advertisementCallback(const Gap::AdvertisementCallbackParams_t *params)
{
    bool name_match = false;

    // parse the advertising payload, looking for data type COMPLETE_LOCAL_NAME
    // The advertising payload is a collection of key/value records where
    // byte 0: length of the record excluding this byte
    // byte 1: The key, it is the type of the data
    // byte [2..N] The value. N is equal to byte0 - 1

    for( uint8_t i = 0; i < params->advertisingDataLen; ++i) {
        const uint8_t record_length = params->advertisingData[i];
        if (record_length == 0) {
            continue;
        }
        const uint8_t type = params->advertisingData[i + 1];
        const uint8_t* value = params->advertisingData + i + 2;
        const uint8_t value_length = record_length - 1;

        if(type == GapAdvertisingData::COMPLETE_LOCAL_NAME) {
            if ((value_length == sizeof(PEER_NAME))
                    && (memcmp(value, PEER_NAME, value_length) == 0)) {
                pc.printf(
                    "\r\nadv peerAddr[%02x %02x %02x %02x %02x %02x] rssi %d, ",
                    params->peerAddr[5], params->peerAddr[4],
                    params->peerAddr[3], params->peerAddr[2],
                    params->peerAddr[1], params->peerAddr[0],
                    params->rssi
                );
                pc.printf(
                    "isScanResponse %u, AdvertisementType %u\r\n",
                    params->isScanResponse, params->type
                );
                name_match = true;
                break;
            }
        }
        i += record_length;
    }
    if( name_match != true ) {
        return;
    }

    pc.printf("Found device name : %s\r\n",PEER_NAME);
    // connections
    ble_uart.gap().connect(params->peerAddr,
                           Gap::ADDR_TYPE_RANDOM_STATIC, NULL, NULL);
}

#endif

void serviceDiscoveryCallback(const DiscoveredService *service)
{
    DBG("service found...\r\n");
    if (service->getUUID().shortOrLong() == UUID::UUID_TYPE_SHORT) {
        DBG(
            "Service UUID-%x attrs[%u %u]\r\n",
            service->getUUID().getShortUUID(),
            service->getStartHandle(),
            service->getEndHandle()
        );
    } else {
        DBG("Service UUID-");
        const uint8_t *longUUIDBytes = service->getUUID().getBaseUUID();
        for (unsigned i = 0; i < UUID::LENGTH_OF_LONG_UUID; i++) {
            DBG("%02x", longUUIDBytes[i]);
        }
        DBG(" attrs[%u %u]\r\n",
            service->getStartHandle(), service->getEndHandle());
    }
}

void characteristicDiscoveryCallback(
    const DiscoveredCharacteristic *characteristicP)
{
    DBG(
        " C UUID-%x valueAttr[%u] props[%x]\r\n",
        characteristicP->getUUID().getShortUUID(),
        characteristicP->getValueHandle(),
        (uint8_t)characteristicP->getProperties().broadcast()
    );
    if (characteristicP->getUUID().getShortUUID()
            == UARTServiceTXCharacteristicShortUUID) {
        DBG("Sevice TX 0x%04x\r\n", UARTServiceTXCharacteristicShortUUID);
        uartTXCharacteristic = *characteristicP;
        connection_tx = true;
    } else if (characteristicP->getUUID().getShortUUID()
               == UARTServiceRXCharacteristicShortUUID) {
        DBG("Sevice RX 0x%04x\r\n", UARTServiceRXCharacteristicShortUUID);
        uartRXCharacteristic = *characteristicP;
        foundUartRXCharacteristic = true;
        connection_rx = true;
    }
}

void discoveryTerminationCallback(Gap::Handle_t connectionHandle)
{
    DBG("terminated SD for handle=%u\r\n", connectionHandle);
}

// Mixed role ******************************************************************
void connectionCallback(const Gap::ConnectionCallbackParams_t *params)
{
    if (params->role == Gap::CENTRAL) {
        pc.printf("connected as Client(Central) (handle = %d)\r\n\r",
                  params->handle);
        connected2server = true;
        connectionHandle = params->handle;
        ble_uart.gattClient().onServiceDiscoveryTermination(
            discoveryTerminationCallback);
        ble_uart.gattClient().launchServiceDiscovery(
            params->handle,
            serviceDiscoveryCallback,
            characteristicDiscoveryCallback
        );
    }
    pc.printf(
        "Client(Central/Myself)       %02x:%02x:%02x:%02x:%02x:%02x\r\n",
        params->ownAddr[5], params->ownAddr[4], params->ownAddr[3],
        params->ownAddr[2], params->ownAddr[1], params->ownAddr[0]
    );
    pc.printf(
        "Connected Server(Peripheral) %02x:%02x:%02x:%02x:%02x:%02x\r\n",
        params->peerAddr[5], params->peerAddr[4], params->peerAddr[3],
        params->peerAddr[2], params->peerAddr[1], params->peerAddr[0]
    );
}

void disconnectionCallback(const Gap::DisconnectionCallbackParams_t *params)
{
    DBG("handle = %d ", params->handle);
    pc.printf(" -> disconnected\r\n", params->handle);
    connected2server = false;
//    connection_1st = false;
    connection_tx = false;
    connection_rx = false;
    if (params->handle == SOFT_DEVICE_FATHER_HANDLE) {
        ble_uart.startAdvertising();                    // restart advertising
    } else {
        ble_uart.gap().startScan(advertisementCallback);// restart scan
    }
}