From 8acb8d5bfa297a415214b0e92f0239206a67ff1f Mon Sep 17 00:00:00 2001
From: Paul <pc235603@gmail.com>
Date: Thu, 19 Jan 2023 10:55:12 +0000
Subject: [PATCH 1/3] Suggested readRegisterRegion changes

---
 src/sfe_bus.cpp | 26 ++++++++++++++------------
 1 file changed, 14 insertions(+), 12 deletions(-)

diff --git a/src/sfe_bus.cpp b/src/sfe_bus.cpp
index 4ed11ef..d0158cd 100644
--- a/src/sfe_bus.cpp
+++ b/src/sfe_bus.cpp
@@ -164,30 +164,29 @@ namespace sfe_KX13X
       return -1;
 
     int i;                   // counter in loop
-    bool bFirstInter = true; // Flag for first iteration - used to send register
+    int failCount = 0; // Keep track of how many times nReturned is != nChunk
 
-    while (numBytes > 0)
+    while ((numBytes > 0) && (failCount < 5)) // Give up after 5 bad requests
     {
       _i2cPort->beginTransmission(addr);
-
-      if (bFirstInter)
-      {
-        _i2cPort->write(reg);
-        bFirstInter = false;
-      }
-
+      _i2cPort->write(reg); // Write the register address we want to read from
       if (_i2cPort->endTransmission() != 0)
-        return -1; // error with the end transmission
+        return -1; // Fail immediately if the transmission isn't successful
 
       // We're chunking in data - keeping the max chunk to kMaxI2CBufferLength
-      nChunk = numBytes > kChunkSize ? kChunkSize : numBytes;
+      // The register address counts as one byte so limit nChunk to kChunkSize -1
+      nChunk = numBytes > (kChunkSize -1) ? (kChunkSize -1) : numBytes;
 
-      nReturned = _i2cPort->requestFrom((int)addr, (int)nChunk, (int)true);
+      nReturned = _i2cPort->requestFrom((int)addr, (int)nChunk, (int)true); // Always send a stop
 
       // No data returned, no dice
       if (nReturned == 0)
         return -1; // error
 
+      // Check we got back as much data as was requested
+      if (nReturned != nChunk)
+        failCount++; // Increment the failCount
+
       // Copy the retrieved data chunk to the current index in the data segment
       for (i = 0; i < nReturned; i++)
       {
@@ -197,6 +196,9 @@ namespace sfe_KX13X
       // Decrement the amount of data recieved from the overall data request amount
       numBytes = numBytes - nReturned;
 
+      // Increment reg by the same ammount
+      reg += nReturned;
+
     } // end while
 
     return 0; // Success

From c316bdb0e0640d92fa301e4f7e9ce135f9e1dac8 Mon Sep 17 00:00:00 2001
From: Paul <pc235603@gmail.com>
Date: Thu, 19 Jan 2023 11:09:36 +0000
Subject: [PATCH 2/3] Trap bad requests

---
 src/sfe_bus.cpp | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/src/sfe_bus.cpp b/src/sfe_bus.cpp
index d0158cd..02934d2 100644
--- a/src/sfe_bus.cpp
+++ b/src/sfe_bus.cpp
@@ -163,10 +163,10 @@ namespace sfe_KX13X
     if (!_i2cPort)
       return -1;
 
-    int i;                   // counter in loop
+    int i;             // counter in loop
     int failCount = 0; // Keep track of how many times nReturned is != nChunk
 
-    while ((numBytes > 0) && (failCount < 5)) // Give up after 5 bad requests
+    while ((numBytes > 0) && (failCount < 2)) // Give up after 2 bad requests
     {
       _i2cPort->beginTransmission(addr);
       _i2cPort->write(reg); // Write the register address we want to read from
@@ -175,7 +175,7 @@ namespace sfe_KX13X
 
       // We're chunking in data - keeping the max chunk to kMaxI2CBufferLength
       // The register address counts as one byte so limit nChunk to kChunkSize -1
-      nChunk = numBytes > (kChunkSize -1) ? (kChunkSize -1) : numBytes;
+      nChunk = numBytes > (kChunkSize - 1) ? (kChunkSize - 1) : numBytes;
 
       nReturned = _i2cPort->requestFrom((int)addr, (int)nChunk, (int)true); // Always send a stop
 
@@ -201,7 +201,7 @@ namespace sfe_KX13X
 
     } // end while
 
-    return 0; // Success
+    return (numBytes == 0 ? 0 : -1); // 0 = success (all bytes read), -1 = error
   }
 
   //////////////////////////////////////////////////////////////////////////////////////////////////

From d0166fcce9b7ecd6bcef60795a6689acd7c31ce4 Mon Sep 17 00:00:00 2001
From: Paul <pc235603@gmail.com>
Date: Thu, 19 Jan 2023 16:50:46 +0000
Subject: [PATCH 3/3] Fix kChunkSize - 1

---
 src/sfe_bus.cpp | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/sfe_bus.cpp b/src/sfe_bus.cpp
index 02934d2..667ed54 100644
--- a/src/sfe_bus.cpp
+++ b/src/sfe_bus.cpp
@@ -174,8 +174,7 @@ namespace sfe_KX13X
         return -1; // Fail immediately if the transmission isn't successful
 
       // We're chunking in data - keeping the max chunk to kMaxI2CBufferLength
-      // The register address counts as one byte so limit nChunk to kChunkSize -1
-      nChunk = numBytes > (kChunkSize - 1) ? (kChunkSize - 1) : numBytes;
+      nChunk = numBytes > kChunkSize ? kChunkSize : numBytes;
 
       nReturned = _i2cPort->requestFrom((int)addr, (int)nChunk, (int)true); // Always send a stop
 
@@ -183,7 +182,8 @@ namespace sfe_KX13X
       if (nReturned == 0)
         return -1; // error
 
-      // Check we got back as much data as was requested
+      // Check we got back as much data as was requested.
+      // (Fringe case. This should never happen... But, you know, it _could_...)
       if (nReturned != nChunk)
         failCount++; // Increment the failCount