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diff --git a/apps/MQTTSN-C-Client/readme.txt b/apps/MQTTSN-C-Client/readme.txt new file mode 100644 index 0000000..e227ee4 --- /dev/null +++ b/apps/MQTTSN-C-Client/readme.txt @@ -0,0 +1,34 @@ +This package provides a reference implementation of the client side of the MQTT-SN (MQTT for Sensor Networks) +protocol. + +The reference implementation consists of the following files:
- application.c This is a sample application which demonstrates how the MQTT-SN client API could be used.
- mqtts/mqtts_api.h This file defines the MQTT-SN client API, which includes verbs such as connect, + disconnect, register, publish, etc. for communicating with the gateway/broker. + The use of these verbs is explained below. It also defines the various parameters + values required for the operation of the MQTT-SN protocol.
- mqtts/mqtts-core.c This file provides the platform-neutral (generic) reference implementation of + the client. It contains the client handling of the MQTT-SN protocol.
- mqtts/mqtts-timer.c This is the implementation of timer functions which are required by the MQTT-SN protocol.
- mqtts/mqtts-timer.h The header file for the timer functions.
- mqtts/gp_api.h This header file defines the interface between the platform-neutral client implementation + and a generic platform. To port the reference implementation to a specific hardware platform, + the functions defined in this header file have to be implemented. +
To port the client reference implementation to a specific hardware platform, the following functions need to be +implemented by the platform (see also file gp_api.h):
1. unsigned char gp_timer_new(void (*timeout_funccb)(void));
This function is called by the client to request the creation of a new timer. The pointer to the function +to be called back when the timer times out is given as parameter. If the timer could be created, +the platform assigns to it a one-byte identity and returns that identity to the MQTT-SN client. The client +will use this identity later on to start, stop, and end the timer. If the timer could not be created, +the value 0xFF should returned.
2. void gp_timer_start(unsigned char id, unsigned char msb, unsigned char lsb);
This function is called by the client to request the start of a timer. The byte id is the identity of the +timer that should be started (this id was returned to the client when the timer was created). The two-byte long +time-out value (in seconds) is indicated by msb and lsb, with msb containing the most significant byte and lsb +the least significant byte of the value.
3. void gp_timer_stop(unsigned char id);
This function is called by the client to request the stop a timer. The identity of the timer to be stopped +is indicated by the parameter id.
4. void gp_timer_end(unsigned char id);
This function is called by the client to indicate that it does not need a timer anymore. The identity of the +timer to be freed is indicated by the parameter id.
5. void gp_network_msg_send(unsigned char *msg, unsigned char *dest, unsigned char length);
This function is called by the client when it wants to send a MQTT-SN message. The pointer *msg points to +the first byte of the array which contains the MQTT-SN message to be sent. The length of the message is indicated +by this first byte. The array containing the destination address is pointed by *dest and its length is indicated +by the parameter length.
6. void gp_network_msg_broadcast(unsigned char *msg, unsigned char radius);
This function is called by the client when it wants to broadcast a MQTT-SN message. The pointer *msg points +to the first byte of the array containing the MQTT-SN message to be broadcasted. The length of the MQTT-SN +message is indicated by this first byte. The parameter radius indicates the broadcast radius.
7. void gpcb_network_msg_received(unsigned char *msg, unsigned char *sender, unsigned char length);
This callback function is called by the platform when it receives a MQTT-SN message. The first byte of the +message received is indicated by the pointer *msg; this first byte also contains the length of the message. +The address of the sender is indicated by the pointer *sender, and its length by the parameter length. +The platform can release the buffer containing the message when this function returns.
8. unsigned char gp_byte_get(unsigned char *msg, unsigned char index);
This function is called by the client to get a byte of a MQTT-SN message just received by the platform +and indicated to it by the callback function gpcb_network_msg_received(…). The pointer *msg is the one +in the callback function, and the parameter index is the index of the byte to get. Note that the first +byte of the MQTT-SN message has the index 1! Note also that the client will call this function only +while it processes the callback function gpcb_network_msg_received(…). +
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