requesting registration status from sim800

src/main.c

@@ -979,7 +979,9 @@ int main(int argc, char* argv[]){
 			if (main_gsm_srl_ctx_ptr->srl_rx_state == SRL_RX_DONE || main_gsm_srl_ctx_ptr->srl_rx_state == SRL_RX_ERROR) {
 
 				// receive callback for communicatio with the modem
-				//gsm_sim800_rx_done_callback(main_gsm_srl_ctx_ptr, &main_gsm_state);
+				gsm_sim800_rx_done_event_handler(main_gsm_srl_ctx_ptr, &main_gsm_state);
+
+				main_gsm_srl_ctx_ptr->srl_rx_state = SRL_RX_IDLE;
 			}
 		}
 

system/include/gsm/sim800c.h

@@ -14,7 +14,9 @@ typedef enum gsm_sim800_state_t {
 	SIM800_UNKNOWN,
 	SIM800_POWERED_OFF,
 	SIM800_NOT_YET_COMM,
-	SIM800_INITIALIZIG,
+	SIM800_HANDSHAKING,
+	SIM800_INITIALIZING,
+	SIM800_INITIALIZING_WAIT_RESPONSE,
 	SIM800_ALIVE,
 	SIM800_GPRS_CONNECTED
 }gsm_sim800_state_t;
@@ -22,6 +24,7 @@ typedef enum gsm_sim800_state_t {
 void gsm_sim800_init(gsm_sim800_state_t * state, uint8_t enable_echo);
 
 void gsm_sim800_pool(srl_context_t * srl_context, gsm_sim800_state_t * state);
-uint8_t gsm_sim800_rx_callback(uint8_t current_data, const uint8_t * const rx_buffer, uint16_t rx_bytes_counter);	// callback used to detect echo
+uint8_t gsm_sim800_rx_terminating_callback(uint8_t current_data, const uint8_t * const rx_buffer, uint16_t rx_bytes_counter);	// callback used to detect echo
+void gsm_sim800_rx_done_event_handler(srl_context_t * srl_context, gsm_sim800_state_t * state);
 
 #endif /* INCLUDE_GSM_SIM800C_H_ */

system/src/gsm/sim800c.c

@@ -11,8 +11,12 @@
 
 #include <string.h>
 
-static const char * AUTOBAUD_STRING = "AT\r\0";
-static const char * OK = "OK\0";
+static const char * AUTOBAUD_STRING 			= "AT\r\0";
+static const char * GET_SIGNAL_LEVEL 			= "AT+CSQ\r\0";
+static const char * GET_NETWORK_REGISTRATION 	= "AT+CREG?\r\0";
+
+static const char * OK = "OK\r\n\0";
+static const char * NETWORK_REGISTRATION = "+CREG\0";
 
 uint32_t gsm_time_of_last_command_send_to_module = 0;
 
@@ -25,6 +29,13 @@ uint8_t gsm_receive_newline_counter = 0;
 // first character of non-echo response from the module
 uint16_t gsm_response_start_idx = 0;
 
+//
+const char * gsm_at_command_sent_last = 0;
+
+uint8_t gsm_waiting_for_command_response = 0;
+
+uint8_t gsm_registration_status = 4;	// unknown
+
 void gsm_sim800_init(gsm_sim800_state_t * state, uint8_t enable_echo) {
 
 	gsm_at_comm_echo = enable_echo;
@@ -47,24 +58,45 @@ void gsm_sim800_pool(srl_context_t * srl_context, gsm_sim800_state_t * state) {
 		srl_send_data(srl_context, (const uint8_t*) AUTOBAUD_STRING, SRL_MODE_ZERO, strlen(AUTOBAUD_STRING), SRL_INTERNAL);
 
 		// switch the state
-		*state = SIM800_INITIALIZIG;
+		*state = SIM800_HANDSHAKING;
 
 		// wait for the handshake to transmit
 		srl_wait_for_tx_completion(srl_context);
 
 		// start data reception
-		//srl_receive_data(srl_context, 8, SRL_NO_START_CHR, SRL_NO_STOP_CHR, SRL_ECHO_DISABLE, 0, 0);
-		srl_receive_data_with_callback(srl_context, gsm_sim800_rx_callback);
+		srl_receive_data_with_callback(srl_context, gsm_sim800_rx_terminating_callback);
 
 		// record when the handshake has been sent
 		gsm_time_of_last_command_send_to_module = main_get_master_time();
 	}
+	else if (*state == SIM800_INITIALIZING && gsm_waiting_for_command_response == 0) {
+
+		// check what command has been sent
+		switch ((uint32_t)gsm_at_command_sent_last) {
+			case 0: {	// no command has been send so far
+
+				// ask for network registration status
+				srl_send_data(srl_context, (const uint8_t*) GET_NETWORK_REGISTRATION, SRL_MODE_ZERO, strlen(GET_NETWORK_REGISTRATION), SRL_INTERNAL);
+
+				// wait for command completion
+				srl_wait_for_tx_completion(srl_context);
+
+				gsm_at_command_sent_last = GET_NETWORK_REGISTRATION;
+
+				gsm_waiting_for_command_response = 1;
+
+				srl_receive_data_with_callback(srl_context, gsm_sim800_rx_terminating_callback);
+
+				break;
+			}
+		}
+	}
 }
 
 /**
  * Callback to be called just after the reception is done
  */
-uint8_t gsm_sim800_rx_callback(uint8_t current_data, const uint8_t * const rx_buffer, uint16_t rx_bytes_counter) {
+uint8_t gsm_sim800_rx_terminating_callback(uint8_t current_data, const uint8_t * const rx_buffer, uint16_t rx_bytes_counter) {
 
 	char current = (char) current_data;
 
@@ -90,9 +122,38 @@ uint8_t gsm_sim800_rx_callback(uint8_t current_data, const uint8_t * const rx_bu
 
 		gsm_receive_newline_counter = 0;
 
+		gsm_waiting_for_command_response = 0;
+
 		return 1;
 	}
 
 	return 0;
 
 }
+
+void gsm_sim800_rx_done_event_handler(srl_context_t * srl_context, gsm_sim800_state_t * state) {
+
+	int comparision_result = 123;
+
+	gsm_waiting_for_command_response = 0;
+
+	// if the library expects to receive a handshake from gsm module
+	if (*state == SIM800_HANDSHAKING) {
+		comparision_result = strcmp(OK, (const char *)(srl_context->srl_rx_buf_pointer + gsm_response_start_idx));
+
+		// if 'OK' has been received from the module
+		if (comparision_result == 0) {
+			*state = SIM800_INITIALIZING;
+		}
+		else {
+			*state = SIM800_NOT_YET_COMM;
+		}
+	}
+	else if (*state == SIM800_INITIALIZING) {
+		comparision_result = strncmp(NETWORK_REGISTRATION, (const char *)(srl_context->srl_rx_buf_pointer + gsm_response_start_idx), 5);
+
+		if (comparision_result == 0) {
+			gsm_registration_status = atoi((const char *)(srl_context->srl_rx_buf_pointer + gsm_response_start_idx + 9));
+		}
+	}
+}