From 1a307eea3debf251107a78dd5ec7e0847fe850fb Mon Sep 17 00:00:00 2001
From: Asbelos <asbelos@btinternet.com>
Date: Sat, 6 Apr 2024 13:19:56 +0100
Subject: [PATCH] Extended consist <R> and <W>

---
 DCC.cpp    | 43 ++++++++++++++++++++++++++++++++++++++++---
 DCCACK.cpp | 17 +++++++++++++++++
 DCCACK.h   |  2 ++
 3 files changed, 59 insertions(+), 3 deletions(-)

diff --git a/DCC.cpp b/DCC.cpp
index a8bc953..f2ab8c3 100644
--- a/DCC.cpp
+++ b/DCC.cpp
@@ -325,8 +325,8 @@ preamble -0- 1 0 A7 A6 A5 A4 A3 A2 -0- 0 ^A10 ^A9 ^A8 0 A1 A0 1 -0- ....
 
 Thus in byte packet form the format is 10AAAAAA, 0AAA0AA1, 000XXXXX
 
-Die Adresse für den ersten erweiterten Zubehördecoder ist wie bei den einfachen
-Zubehördecodern die Adresse 4 = 1000-0001 0111-0001 . Diese Adresse wird in
+Die Adresse f�r den ersten erweiterten Zubeh�rdecoder ist wie bei den einfachen
+Zubeh�rdecodern die Adresse 4 = 1000-0001 0111-0001 . Diese Adresse wird in
 Anwenderdialogen als Adresse 1 dargestellt.
 
 This means that the first address shown to the user as "1" is mapped
@@ -500,6 +500,36 @@ const ackOp FLASH READ_CV_PROG[] = {
 
 const ackOp FLASH LOCO_ID_PROG[] = {
       BASELINE,
+      // first check cv20 for extended addressing
+      SETCV, (ackOp)20,     // CV 19 is extended
+      SETBYTE, (ackOp)0,
+      VB, WACK, ITSKIP,     // skip past extended section if cv20 is zero
+      // read cv20 and 19 and merge 
+      STARTMERGE,           // Setup to read cv 20
+      V0, WACK, MERGE,
+      V0, WACK, MERGE,
+      V0, WACK, MERGE,
+      V0, WACK, MERGE,
+      V0, WACK, MERGE,
+      V0, WACK, MERGE,
+      V0, WACK, MERGE,
+      V0, WACK, MERGE,
+      VB, WACK, NAKSKIP, // bad read of cv20, assume its 0 
+      STASHLOCOID,   // keep cv 20 until we have cv19 as well.
+      SETCV, (ackOp)19, 
+      STARTMERGE,           // Setup to read cv 19
+      V0, WACK, MERGE,
+      V0, WACK, MERGE,
+      V0, WACK, MERGE,
+      V0, WACK, MERGE,
+      V0, WACK, MERGE,
+      V0, WACK, MERGE,
+      V0, WACK, MERGE,
+      V0, WACK, MERGE,
+      VB, WACK, NAKFAIL,  // cant recover if cv 19 unreadable
+      COMBINE1920,  // Combile byte with stash and callback
+// end of advanced 20,19 check
+      SKIPTARGET,
       SETCV, (ackOp)19,     // CV 19 is consist setting
       SETBYTE, (ackOp)0,
       VB, WACK, ITSKIP,     // ignore consist if cv19 is zero (no consist)
@@ -566,6 +596,10 @@ const ackOp FLASH LOCO_ID_PROG[] = {
 
 const ackOp FLASH SHORT_LOCO_ID_PROG[] = {
       BASELINE,
+      // Clear consist CV 19,20
+      SETCV,(ackOp)20,
+      SETBYTE, (ackOp)0,
+      WB,WACK,     // ignore dedcoder without cv20 support
       SETCV,(ackOp)19,
       SETBYTE, (ackOp)0,
       WB,WACK,     // ignore dedcoder without cv19 support
@@ -583,7 +617,10 @@ const ackOp FLASH SHORT_LOCO_ID_PROG[] = {
 
 const ackOp FLASH LONG_LOCO_ID_PROG[] = {
       BASELINE,
-      // Clear consist CV 19
+      // Clear consist CV 19,20
+      SETCV,(ackOp)20,
+      SETBYTE, (ackOp)0,
+      WB,WACK,     // ignore dedcoder without cv20 support
       SETCV,(ackOp)19,
       SETBYTE, (ackOp)0,
       WB,WACK,     // ignore decoder without cv19 support
diff --git a/DCCACK.cpp b/DCCACK.cpp
index 8a074b4..517d513 100644
--- a/DCCACK.cpp
+++ b/DCCACK.cpp
@@ -314,6 +314,14 @@ void DCCACK::loop() {
           callback( LONG_ADDR_MARKER | ( ackManagerByte + ((ackManagerStash - 192) << 8)));
           return;
 
+     case COMBINE1920:
+          // ackManagerStash is  cv20, ackManagerByte is CV 19
+          // This will not be called if cv20==0
+          ackManagerByte &= 0x7F;  // ignore direction marker
+          ackManagerByte %=100;    // take last 2 decimal digits 
+          callback( ackManagerStash*100+ackManagerByte);
+          return;
+
      case ITSKIP:
           if (!ackReceived) break;
           // SKIP opcodes until SKIPTARGET found
@@ -322,6 +330,15 @@ void DCCACK::loop() {
             opcode=GETFLASH(ackManagerProg);
           }
           break;
+
+     case NAKSKIP:
+          if (ackReceived) break;
+          // SKIP opcodes until SKIPTARGET found
+          while (opcode!=SKIPTARGET) {
+            ackManagerProg++;
+            opcode=GETFLASH(ackManagerProg);
+          }
+          break;
      case SKIPTARGET:
           break;
      default:
diff --git a/DCCACK.h b/DCCACK.h
index 7d39319..fa03387 100644
--- a/DCCACK.h
+++ b/DCCACK.h
@@ -56,6 +56,8 @@ enum ackOp : byte
   STASHLOCOID,      // keeps current byte value for later
   COMBINELOCOID,    // combines current value with stashed value and returns it
   ITSKIP,           // skip to SKIPTARGET if ack true
+  NAKSKIP,          // skip to SKIPTARGET if ack false
+  COMBINE1920,      // combine cvs 19 and 20 and callback
   SKIPTARGET = 0xFF // jump to target
 };