Update MCP23S17.cpp

RobTillaart · Jun 11, 2024 · 3c7660d · 3c7660d
1 parent b36c997
commit 3c7660d
Showing 1 changed file with 6 additions and 0 deletions.
diff --git a/MCP23S17.cpp b/MCP23S17.cpp
@@ -71,6 +71,12 @@ bool MCP23S17::begin(bool pullup)
   //    1 = Sequential operation disabled, address pointer does not increment.
   //    0 = Sequential operation enabled, address pointer increments.
   //  if (! writeReg(MCP23017_IOCR, MCP23017_IOCR_SEQOP)) return false;
+  uint8_t reg = readReg(MCP23017_IOCR);
+  if (reg & MCP23017_IOCR_SEQOP)  //  check if already zero
+  {
+    reg &= ~MCP23017_IOCR_SEQOP;  //  clear SEQOP bit for sequential read/write
+    if (! writeReg(MCP23017_IOCR, reg)) return false;
+  }
 
   if (pullup)
   {