The driver for the ESP32 WiFi module

The ESP32 WiFi driver for Mbed OS

The Mbed OS driver for the ESP32 WiFi module.

Firmware version

How to write mbed-os compatible firmware : https://github.com/d-kato/GR-Boards_ESP32_Serial_Bridge

Restrictions

  • Setting up an UDP server is not possible
  • The serial port does not have hardware flow control enabled. The AT command set does not either have a way to limit the download rate. Therefore, downloading anything larger than the serial port input buffer is unreliable. An application should be able to read fast enough to stay ahead of the network. This affects mostly the TCP protocol where data would be lost with no notification. On UDP, this would lead to only packet losses which the higher layer protocol should recover from.

ESP32Interface.h

Committer:
dkato
Date:
14 months ago
Revision:
2:cb5c0d3fa776
Parent:
1:5d78eedef723

File content as of revision 2:cb5c0d3fa776:

/* ESP32 implementation of NetworkInterfaceAPI
 * Copyright (c) 2017 Renesas Electronics Corporation
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#ifndef ESP32_INTERFACE_H
#define ESP32_INTERFACE_H

#include "mbed.h"
#include "ESP32Stack.h"

/** ESP32Interface class
 *  Implementation of the NetworkStack for the ESP32
 */
class ESP32Interface : public ESP32Stack, public WiFiInterface
{
public:
    /** ESP32Interface lifetime
     * @param en        EN pin  (If not used this pin, please set "NC")
     * @param io0       IO0 pin (If not used this pin, please set "NC")
     * @param tx        TX pin
     * @param rx        RX pin
     * @param debug     Enable debugging
     * @param rts       RTS pin
     * @param cts       CTS pin
     * @param baudrate  The baudrate of the serial port (default = 230400).
     */
    ESP32Interface(PinName en, PinName io0, PinName tx, PinName rx, bool debug = false,
                   PinName rts = NC, PinName cts = NC, int baudrate = 230400);

    /** ESP32Interface lifetime
     * @param tx        TX pin
     * @param rx        RX pin
     * @param debug     Enable debugging
     */
    ESP32Interface(PinName tx, PinName rx, bool debug = false);

    /** Set a static IP address
     *
     *  Configures this network interface to use a static IP address.
     *  Implicitly disables DHCP, which can be enabled in set_dhcp.
     *  Requires that the network is disconnected.
     *
     *  @param ip_address Null-terminated representation of the local IP address
     *  @param netmask    Null-terminated representation of the local network mask
     *  @param gateway    Null-terminated representation of the local gateway
     *  @return           0 on success, negative error code on failure
     */
    virtual nsapi_error_t set_network(
            const char *ip_address, const char *netmask, const char *gateway);

    /** Enable or disable DHCP on the network
     *
     *  Enables DHCP on connecting the network. Defaults to enabled unless
     *  a static IP address has been assigned. Requires that the network is
     *  disconnected.
     *
     *  @param dhcp     True to enable DHCP
     *  @return         0 on success, negative error code on failure
     */
    virtual nsapi_error_t set_dhcp(bool dhcp);

    /** Start the interface
     *
     *  Attempts to connect to a WiFi network. Requires ssid and passphrase to be set.
     *  If passphrase is invalid, NSAPI_ERROR_AUTH_ERROR is returned.
     *
     *  @return         0 on success, negative error code on failure
     */
    virtual int connect();

    /** Start the interface
     *
     *  Attempts to connect to a WiFi network.
     *
     *  @param ssid      Name of the network to connect to
     *  @param pass      Security passphrase to connect to the network
     *  @param security  Type of encryption for connection (Default: NSAPI_SECURITY_NONE)
     *  @param channel   This parameter is not supported, setting it to anything else than 0 will result in NSAPI_ERROR_UNSUPPORTED
     *  @return          0 on success, or error code on failure
     */
    virtual int connect(const char *ssid, const char *pass, nsapi_security_t security = NSAPI_SECURITY_NONE,
                                  uint8_t channel = 0);

    /** Set the WiFi network credentials
     *
     *  @param ssid      Name of the network to connect to
     *  @param pass      Security passphrase to connect to the network
     *  @param security  Type of encryption for connection
     *                   (defaults to NSAPI_SECURITY_NONE)
     *  @return          0 on success, or error code on failure
     */
    virtual int set_credentials(const char *ssid, const char *pass, nsapi_security_t security = NSAPI_SECURITY_NONE);

    /** Set the WiFi network channel - NOT SUPPORTED
     *
     * This function is not supported and will return NSAPI_ERROR_UNSUPPORTED
     *
     *  @param channel   Channel on which the connection is to be made, or 0 for any (Default: 0)
     *  @return          Not supported, returns NSAPI_ERROR_UNSUPPORTED
     */
    virtual int set_channel(uint8_t channel);

    /** Stop the interface
     *  @return             0 on success, negative on failure
     */
    virtual int disconnect();

    /** Get the internally stored IP address
     *  @return             IP address of the interface or null if not yet connected
     */
    virtual const char *get_ip_address();

    /** Get the internally stored MAC address
     *  @return             MAC address of the interface
     */
    virtual const char *get_mac_address();

     /** Get the local gateway
     *
     *  @return         Null-terminated representation of the local gateway
     *                  or null if no network mask has been recieved
     */
    virtual const char *get_gateway();

    /** Get the local network mask
     *
     *  @return         Null-terminated representation of the local network mask
     *                  or null if no network mask has been recieved
     */
    virtual const char *get_netmask();

    /** Gets the current radio signal strength for active connection
     *
     * @return          Connection strength in dBm (negative value)
     */
    virtual int8_t get_rssi();

    /** Scan for available networks
     *
     * This function will block.
     *
     * @param  ap       Pointer to allocated array to store discovered AP
     * @param  count    Size of allocated @a res array, or 0 to only count available AP
     * @param  timeout  Timeout in milliseconds; 0 for no timeout (Default: 0)
     * @return          Number of entries in @a, or if @a count was 0 number of available networks, negative on error
     *                  see @a nsapi_error
     */
    virtual int scan(WiFiAccessPoint *res, unsigned count);

    /** Translates a hostname to an IP address with specific version
     *
     *  The hostname may be either a domain name or an IP address. If the
     *  hostname is an IP address, no network transactions will be performed.
     *
     *  If no stack-specific DNS resolution is provided, the hostname
     *  will be resolve using a UDP socket on the stack.
     *
     *  @param address  Destination for the host SocketAddress
     *  @param host     Hostname to resolve
     *  @param version  IP version of address to resolve, NSAPI_UNSPEC indicates
     *                  version is chosen by the stack (defaults to NSAPI_UNSPEC)
     *  @return         0 on success, negative error code on failure
     */
    using NetworkInterface::gethostbyname;

    /** Add a domain name server to list of servers to query
     *
     *  @param addr     Destination for the host address
     *  @return         0 on success, negative error code on failure
     */
    using NetworkInterface::add_dns_server;

    /** Register callback for status reporting
     *
     *  The specified status callback function will be called on status changes
     *  on the network. The parameters on the callback are the event type and
     *  event-type dependent reason parameter.
     *
     *  In ESP32 the callback will be called when processing OOB-messages via
     *  AT-parser. Do NOT call any ESP8266Interface -functions or do extensive
     *  processing in the callback.
     *
     *  @param status_cb The callback for status changes
     */
    virtual void attach(mbed::Callback<void(nsapi_event_t, intptr_t)> status_cb);

    /** Get the connection status
     *
     *  @return         The connection status according to ConnectionStatusType
     */
    virtual nsapi_connection_status_t get_connection_status() const;

    /** Provide access to the NetworkStack object
     *
     *  @return The underlying NetworkStack object
     */
    virtual NetworkStack *get_stack()
    {
        return this;
    }

private:
    bool _dhcp;
    char _ap_ssid[33]; /* 32 is what 802.11 defines as longest possible name; +1 for the \0 */
    char _ap_pass[64]; /* The longest allowed passphrase */
    nsapi_security_t _ap_sec;
    char _ip_address[NSAPI_IPv6_SIZE];
    char _netmask[NSAPI_IPv4_SIZE];
    char _gateway[NSAPI_IPv4_SIZE];
    nsapi_connection_status_t _connection_status;
    Callback<void(nsapi_event_t, intptr_t)> _connection_status_cb;

    void set_connection_status(nsapi_connection_status_t connection_status);
    void wifi_status_cb(int8_t wifi_status);
};

#endif