Calculate gaps in bits, not bytes (more accurate). Pad the end of the…

… track to avoid weirdness reading the last sector.
davidgiven · Apr 30, 2024 · 8876aae · 8876aae
1 parent 3e053b3
commit 8876aae
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Showing 2 changed files with 7 additions and 11 deletions.
diff --git a/arch/tartu/encoder.cc b/arch/tartu/encoder.cc
@@ -28,18 +28,19 @@ class TartuEncoder : public Encoder
         _bits.resize(bitsPerRevolution);
         _cursor = 0;
 
-        writeFillerRawBytesUs(_config.gap1_us());
+        writeFillerRawBitsUs(_config.gap1_us());
         bool first = true;
         for (const auto& sectorData : sectors)
         {
             if (!first)
-                writeFillerRawBytesUs(_config.gap4_us());
+                writeFillerRawBitsUs(_config.gap4_us());
             first = false;
             writeSector(sectorData);
         }
 
         if (_cursor > _bits.size())
             error("track data overrun");
+        writeFillerRawBitsUs(_config.target_rotational_period_ms() * 1000.0);
 
         std::unique_ptr<Fluxmap> fluxmap(new Fluxmap);
         fluxmap->appendBits(_bits,
@@ -67,13 +68,11 @@ class TartuEncoder : public Encoder
         }
     }
 
-    void writeFillerRawBytesUs(double us)
+    void writeFillerRawBitsUs(double us)
     {
-        uint16_t byte = _config.gap_fill_byte();
-        unsigned count = (us / _clockRateUs) / 16;
-        fmt::print("count={}\n", count);
+        unsigned count = (us / _clockRateUs) / 2;
         for (int i = 0; i < count; i++)
-            writeRawBits(byte, 16);
+            writeRawBits(0b10, 2);
     };
 
     void writeSector(const std::shared_ptr<const Sector>& sectorData)
@@ -90,7 +89,7 @@ class TartuEncoder : public Encoder
             writeBytes(bytes);
         }
 
-        writeFillerRawBytesUs(_config.gap3_us());
+        writeFillerRawBitsUs(_config.gap3_us());
         writeRawBits(_config.data_marker(), 64);
         {
             Bytes bytes;

diff --git a/arch/tartu/tartu.proto b/arch/tartu/tartu.proto
@@ -24,7 +24,4 @@ message TartuEncoderProto {
     optional uint64 data_marker = 7
         [ default = 0xaaaaaaaa44895545,
           (help) = "64-bit raw bit pattern of data record marker" ];
-    optional uint32 gap_fill_byte = 8
-        [ default = 0xaaaa,
-          (help) = "16-bit raw bit pattern of fill byte" ];
 }