add option to set the link bit in the 1A group

src/ascii_cmd.c

@@ -72,6 +72,16 @@ static void handle_ertp(char *arg, RDSModulator* mod, char* output) {
 	}
 }
 
+static void handle_linkage(char *arg, RDSModulator* mod, char* output) {
+	if(arg[0] == '\0') {
+		mod->enc->data[mod->enc->program].eon_linkage = 0;
+		return;
+	}
+
+	mod->enc->data[mod->enc->program].eon_linkage = atoi(arg);
+	strcpy(output, "+\0");
+}
+
 static void handle_lps(char *arg, RDSModulator* mod, char* output) {
 	arg[LPS_LENGTH * 2] = 0;
 	set_rds_lps(mod->enc, arg);
@@ -495,6 +505,7 @@ static const command_handler_t commands_eq5[] = {
 	{"DPTY", handle_dpty, 4},
 	{"SLCD", handle_slcd, 4},
 	{"ERTP", handle_ertp, 4},
+	{"LINK", handle_link, 4},
 };
 
 static const command_handler_t commands_eq2[] = {

src/rds.c

@@ -365,12 +365,14 @@ static void get_rds_lps_group(RDSEncoder* enc, RDSGroup *group) {
 
 static void get_rds_ecc_group(RDSEncoder* enc, RDSGroup *group) {
 	group->b |= 1 << 12;
-	group->c = enc->data[enc->program].ecc;
+	group->c = enc->state[enc->program].eon_linkage << 15;
+	group->c |= enc->data[enc->program].ecc;
 }
 
 static void get_rds_slcdata_group(RDSEncoder* enc, RDSGroup *group) {
 	group->b |= 1 << 12;
-	group->c = 0x6000;
+	group->c = enc->state[enc->program].eon_linkage << 15;
+	group->c |= 0x6000;
 	group->c |= enc->data[enc->program].slc_data;
 }
 

src/rds.h

@@ -166,6 +166,8 @@ typedef struct {
 	uint8_t af_state : 6;
 	uint8_t af_oda_state : 6;
 
+	uint8_t eon_linkage : 1;
+
 	uint16_t last_stream0_group[3];
 } RDSState;