Fix an error in the ordering of fields in zm_transition_s structure; update documentation

system/zmodem/README.txt

@@ -4,6 +4,8 @@ README
 Using NuttX Zmodem with a Linux Host
 ====================================
 
+    Sending Files from the Target to the Linux Host PC
+    --------------------------------------------------
     The NuttX Zmodem commands have been verified against the rzsz programs
     running on a Linux PC.  To send a file to the PC, first make sure that
     the serial port is configured to work with the board:
@@ -11,7 +13,7 @@ Using NuttX Zmodem with a Linux Host
       $ sudo stty -F /dev/ttyS0 57600
       $ sudo stty -F /dev/ttyS0
 
-    start rz on the Linux host:
+    Start rz on the Linux host:
 
       $ sudo rz </dev/ttyS0 >/dev/ttyS0
 
@@ -38,4 +40,31 @@ Using NuttX Zmodem with a Linux Host
     Where filename is the full path to the file to send (i.e., it begins
     with the '/' character).
 
- 
+    Receiving Files on the Target from the Linux Host PC
+    ----------------------------------------------------
+    To send a file to the target, first make sure that the serial port on the
+    host is configured to work with the board:
+
+      $ sudo stty -F /dev/ttyS0 57600
+      $ sudo stty -F /dev/ttyS0
+
+    Start rz on the on the target:
+
+      nsh> rz -d /dev/ttyS1
+
+    Then use the sz command on Linux to send the file to the target:
+
+      $ sudo sz <filename> t </dev/ttyS0 >/dev/ttyS0
+
+    Where <filename> is the file that you want to send.
+
+    The resulting file will be found where you have configured the Zmodem
+    "sandbox" via CONFIG_SYSTEM_ZMODEM_MOUNTPOINT.
+
+    You can add the az -v option multiple times, each increases the level
+    of debug output.  If you want to capture the Linux rz output, then
+    re-direct stderr to a log file by adding 2>az.log to the end of the
+    rz command.
+
+    If you don't have the az command on your Linux box, the package to
+    install rzsz (or possibily lrzsz).

system/zmodem/zm.h

@@ -287,8 +287,8 @@ typedef int (*action_t)(FAR struct zm_state_s *pzm);
 struct zm_transition_s
 {
   uint8_t    type;           /* Event (Frame type) */
-  uint8_t    next;           /* Next state */
   bool       bdiscard;       /* TRUE: discard buffered input */
+  uint8_t    next;           /* Next state */
   action_t   action;         /* Transition action */
 };
 

system/zmodem/zm_receive.c

@@ -81,14 +81,14 @@
  *                <---- ZRINIT        ZMR_START
  *   ZSINIT       ---->
  *                <---- ZACK          ZMR_INITWAIT
- *   ZFILE        ----> 
+ *   ZFILE        ---->
  *                <---- ZRPOS         ZMR_FILEINFO
  *   ZDATA        ---->
  *                <---- ZCRC          ZMR_CRCWAIT
  *   ZCRC         ---->               ZMR_READREADY
  *   Data packets ---->               ZMR_READING
  *   Last packet  ---->
- *   ZEOF         ----> 
+ *   ZEOF         ---->
  *                <---- ZRINIT
  *   ZFIN         ---->
  *                <---- ZFIN          ZMR_FINISH
@@ -955,7 +955,7 @@ static int zmr_zfin(FAR struct zm_state_s *pzm)
    * meaning that we are all done.
    */
 
-  zmdbg("PSTATE %d:%d->%d.%d:  send ZFIN\n",
+  zmdbg("PSTATE %d:%d->%d.%d:  Send ZFIN\n",
          pzm->pstate, pzm->psubstate, PSTATE_IDLE, PIDLE_ZPAD);
   zmdbg("ZMR_STATE %d\n", pzm->state);