Detach explicit polling for acks from rx state machine.

diff --git a/gpsbabel/magproto.c b/gpsbabel/magproto.c
index a8cccb08a69920ff921db5590ce919d91d86f019..54c9f1ba4bb65d1cab84a10aef6ca50be292d706 100644 (file)
--- a/gpsbabel/magproto.c
+++ b/gpsbabel/magproto.c
@@ -37,10 +37,12 @@ extern gpsdata_type objective;
 static char * termread(char *ibuf, int size);
 static void termwrite(char *obuf, int size);
 static double mag2degrees(double mag_val);
+static void mag_readmsg(void);
 
 typedef enum {
        mrs_handoff = 0,
-       mrs_handon
+       mrs_handon,
+       mrs_awaiting_ack
 } mag_rxstate;
 
 /*
@@ -235,57 +237,78 @@ static void
 mag_writemsg(const char * const buf)
 {
        unsigned int osum = mag_checksum(buf);
+       int retry_cnt = 20;
        int i;
        char obuf[1000];
 
        if (debug_serial) {
                fprintf(stderr,"WRITE: $%s*%02X\r\n",buf, osum);
        }
-#if 0
-       retry:
-#endif
+
+    retry:
+
        i = sprintf(obuf, "$%s*%02X\r\n",buf, osum);
        termwrite(obuf, i);
-
-#if 0
-       if (magrxstate == mrs_handon) {
+       if (magrxstate == mrs_handon || magrxstate == mrs_awaiting_ack) {
+               magrxstate = mrs_awaiting_ack;
                mag_readmsg();
                if (last_rx_csum != osum) {
-fprintf(stderr, "E");
-                       goto retry;
+                       if (debug_serial) {
+                               fprintf(stderr, "COMM ERROR: Expected %02x, got %02x", 
+                                               osum, last_rx_csum);
+                       }
+                       if (retry_cnt--)
+                               goto retry;
+                       else
+                               fatal(MYNAME 
+                                       ": Too many communication errors.\n");
                }
        }
-#endif
 } 
 
 static void
 mag_writeack(int osum)
 {
        char obuf[200];
+       char nbuf[200];
+       int i;
+       unsigned int nsum;
+
        if (is_file) {
                return;
        }
-       sprintf(obuf, "PMGNCSM,%02X", osum);
-       mag_writemsg(obuf);
+
+       i = sprintf(nbuf, "PMGNCSM,%02X", osum);
+       nsum = mag_checksum(nbuf);
+       i = sprintf(obuf, "$%s*%02X\r\n",nbuf, nsum);
+
+       if (debug_serial) {
+               fprintf(stderr,"ACK WRITE: %s",obuf);
+       }
+       /*
+        * Don't call mag_writemsg here so we don't get into ack feedback
+        * loops.
+        */
+       termwrite(obuf, i);
 }
 
 static void
 mag_handon(void)
 {
-       magrxstate = mrs_handon;
-       
        if (!is_file) {
                mag_writemsg("PMGNCMD,HANDON");
        }
+       magrxstate = mrs_handon;
+       
 }
 
 static void
 mag_handoff(void)
 {
-       magrxstate = mrs_handoff;
        if (!is_file) {
                mag_writemsg("PMGNCMD,HANDOFF");
        }
+       magrxstate = mrs_handoff;
 }
 
 void
@@ -385,6 +408,7 @@ retry:
        }
        if (IS_TKN("$PMGNCSM,")) {
                last_rx_csum = strtoul(&ibuf[9], NULL, 16);
+               magrxstate = mrs_handon;
                return;
        } 
        if (strncmp(ibuf, "$PMGNWPT,", 7) == 0) {
@@ -665,6 +689,7 @@ mag_rd_init(const char *portname, const char *args)
                ignore_unable = 1;
                mag_writemsg("PMGNCMD,NMEAOFF");
        }
+
        return;
 }
 
@@ -986,8 +1011,9 @@ mag_read(void)
                        fatal(MYNAME ": Routes are not yet supported\n");
        }
 
-       while (!found_done)
+       while (!found_done) {
                mag_readmsg();
+       }
 }
 
 static
@@ -1050,7 +1076,6 @@ mag_waypt_pr(const waypoint *waypointp)
        free(odesc);
 
        if (!is_file) {
-               mag_readmsg();
                if (mag_error) {
                        fprintf(stderr, "Protocol error Writing '%s'\n", obuf);
                }
@@ -1061,17 +1086,6 @@ mag_waypt_pr(const waypoint *waypointp)
 static void
 mag_write(void)
 {
-       if (!is_file) {
-               mag_readmsg();
-#if !__WIN32__
-               /*
-                * I have no idea why this is fatal under Windows.
-                */
-               mag_readmsg();
-               mag_readmsg();
-               mag_readmsg();
-#endif
-       }
        /* 
         * Whitespace is actually legal, but since waypoint name length is
         * only 8 bytes, we'll conserve them.