Merge pull request #49 from josevcm/develop

handle EGT
josevcm · Dec 1, 2024 · 6f57698 · 6f57698
2 parents 16c1b5a + ada0993
commit 6f57698
Showing 1 changed file with 20 additions and 7 deletions.
diff --git a/src/nfc-lib/lib-lab/lab-logic/src/main/cpp/tech/Iso7816.cpp b/src/nfc-lib/lib-lab/lab-logic/src/main/cpp/tech/Iso7816.cpp
@@ -926,24 +926,37 @@ struct Iso7816::Impl : IsoTech
          case IsoRequestFrame:
          {
             frameStatus.frameType = IsoResponseFrame;
-            frameStatus.guardTime = protocolStatus.characterGuardTime - GT_THRESHOLD * protocolStatus.elementaryTime;
-            frameStatus.waitingTime = protocolStatus.blockWaitingTime + WT_THRESHOLD * protocolStatus.elementaryTime;
             break;
          }
          case IsoResponseFrame:
          {
             frameStatus.frameType = IsoRequestFrame;
-            frameStatus.guardTime = protocolStatus.characterGuardTime - GT_THRESHOLD * protocolStatus.elementaryTime;
-            frameStatus.waitingTime = protocolStatus.blockWaitingTime + WT_THRESHOLD * protocolStatus.elementaryTime;
             break;
          }
-         default:
+      }
+
+      // N=255 has a protocol-dependent meaning:
+      //  - GT=12 ETU under protocol T=0 nad during PPS (Protocol and Parameters Selection)
+      //  - GT=11 ETU under protocol T=1 (corresponding to 1 start bit, 8 data bits, 1 parity bit, and 1 stop bit; with no error indication)
+      if (protocolStatus.extraGuardTimeUnits == 255)
+      {
+         if (protocolStatus.protocolType == PROTO_T0)
          {
-            frameStatus.guardTime = protocolStatus.characterGuardTime - GT_THRESHOLD * protocolStatus.elementaryTime;
-            frameStatus.waitingTime = protocolStatus.characterWaitingTime + WT_THRESHOLD * protocolStatus.elementaryTime;
+            frameStatus.guardTime = (12 - GT_THRESHOLD) * protocolStatus.elementaryTime;
          }
+         else
+         {
+            frameStatus.guardTime = (11 - GT_THRESHOLD) * protocolStatus.elementaryTime;
+         }
+      }
+      else
+      {
+         frameStatus.guardTime = protocolStatus.characterGuardTime - GT_THRESHOLD * protocolStatus.elementaryTime;
       }
 
+      // waiting time is set by default to 960 ETUs for T=0 and 9600 ETUs for T=1
+      frameStatus.waitingTime = protocolStatus.characterWaitingTime + WT_THRESHOLD * protocolStatus.elementaryTime;
+
       // clear search to detect first start bit of next frame
       modulationStatus.searchStartTime = 0;
       modulationStatus.searchEndTime = 0;