0.2.0 LC7822

Author: RobTillaart

libraries/LC7822/CHANGELOG.md

@@ -6,6 +6,21 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/)
 and this project adheres to [Semantic Versioning](http://semver.org/).
 
 
+## [0.2.0] - 2025-12-21
+- fix #2, cePin bug
+- fix #3, add address as parameter to **begin()**
+- fix #5, addresses of the devices.
+- fix shift order in updateDevice()
+- refactor class hierarchy, for address check.
+- make **sPin** optional, needed for hardwired sPins.
+- add **getAddress()** convenience function.
+- add **LC7822_fixed_address.ino** example
+- add **LC7822_two_device.ino** example
+- update readme.md a lot.
+- minor edits
+
+----
+
 ## [0.1.0] - 2025-12-20
 - initial version
 

libraries/LC7822/LC7822.cpp

@@ -2,17 +2,17 @@
 //    FILE: LC7822.cpp
 //  AUTHOR: Rob Tillaart
 //    DATE: 2025-12-20
-// VERSION: 0.1.0
+// VERSION: 0.2.0
 // PURPOSE: Arduino library for the LC7822 8 channel analogue switch.
 //     URL: https://github.com/RobTillaart/LC7822
 
 
 #include "LC7822.h"
 
 
-LC7822::LC7822(uint8_t dataPin, uint8_t clockPin, uint8_t cePin, uint8_t sPin, uint8_t resetPin)
+LC782X::LC782X(uint8_t dataPin, uint8_t clockPin, uint8_t cePin, uint8_t sPin, uint8_t resetPin)
 {
-  _address  = 11;
+  _address  = 0;
   _dataPin  = dataPin;
   _clockPin = clockPin;
   _cePin    = cePin;
@@ -22,17 +22,22 @@ LC7822::LC7822(uint8_t dataPin, uint8_t clockPin, uint8_t cePin, uint8_t sPin, u
 }
 
 
-bool LC7822::begin()
+bool LC782X::begin(uint8_t address)
 {
+  _address = address;
+
   pinMode(_dataPin, OUTPUT);
   digitalWrite(_dataPin, LOW);
   pinMode(_clockPin, OUTPUT);
   digitalWrite(_clockPin, LOW);
   pinMode(_cePin, OUTPUT);
   digitalWrite(_cePin, LOW);
-  pinMode(_sPin, OUTPUT);
-  digitalWrite(_sPin, LOW);
-
+  //  optional pins.
+  if (_sPin != 255)
+  {
+    pinMode(_sPin, OUTPUT);
+    digitalWrite(_sPin, LOW);
+  }
   if (_resetPin != 255)
   {
     pinMode(_resetPin, OUTPUT);
@@ -42,7 +47,7 @@ bool LC7822::begin()
 }
 
 
-bool LC7822::reset()
+bool LC782X::reset()
 {
   if (_resetPin != 255)
   {
@@ -58,21 +63,21 @@ bool LC7822::reset()
 }
 
 
-bool LC7822::setAll(uint8_t value)
+bool LC782X::setAll(uint8_t value)
 {
   _switches = value;
   _updateDevice();
   return true;
 }
 
 
-uint8_t LC7822::getAll()
+uint8_t LC782X::getAll()
 {
   return _switches;
 }
 
 
-bool LC7822::setSwitch(uint8_t sw, bool val)
+bool LC782X::setSwitch(uint8_t sw, bool val)
 {
   if (sw > 7) return false;
   if (val)  //  ON
@@ -88,7 +93,7 @@ bool LC7822::setSwitch(uint8_t sw, bool val)
 }
 
 
-bool LC7822::getSwitch(uint8_t sw)
+bool LC782X::getSwitch(uint8_t sw)
 {
   if (sw > 7) return false;
   return _switches & (1 << sw);
@@ -99,13 +104,13 @@ bool LC7822::getSwitch(uint8_t sw)
 //
 //  PROTECTED
 //
-void LC7822::_updateDevice()
+void LC782X::_updateDevice()
 {
-  //  select this device
-  digitalWrite(_sPin, HIGH);
+  //  select this device only if sPin is defined.
+  if (_sPin != 255) digitalWrite(_sPin, HIGH);
 
-  //  send address == 4 bits
-  for (uint8_t mask = 0x08; mask > 0x00; mask >>= 1)
+  //  send address == 4 bits - A0 first
+  for (uint8_t mask = 0x01; mask < 0x10; mask <<= 1)
   {
     digitalWrite(_dataPin, (_address & mask));
     if (_microDelay) delayMicroseconds(_microDelay);
@@ -114,40 +119,73 @@ void LC7822::_updateDevice()
     digitalWrite(_clockPin, LOW);
   }
 
-  // send data == 8 bits
+  // send data == 8 bits - SW1 first
   if (_microDelay) delayMicroseconds(_microDelay);
   digitalWrite(_cePin, HIGH);
   if (_microDelay) delayMicroseconds(_microDelay);
 
-  for (uint8_t mask = 0x80; mask > 0x00; mask >>= 1)
+  for (uint8_t mask = 0x01; mask != 0x00; mask <<= 1)
   {
     digitalWrite(_dataPin, (_switches & mask));
     if (_microDelay) delayMicroseconds(_microDelay);
     digitalWrite(_clockPin, HIGH);
     if (_microDelay) delayMicroseconds(_microDelay);
     digitalWrite(_clockPin, LOW);
   }
-  digitalWrite(_cePin, HIGH);
+  digitalWrite(_cePin, LOW);
 
-  digitalWrite(_sPin, LOW);
+  if (_sPin != 255) digitalWrite(_sPin, LOW);
 }
 
 
 //////////////////////////////////////////////////
 //
-//  DERIVED
+//  DERIVED LC7821
 //
 LC7821::LC7821(uint8_t dataPin, uint8_t clockPin, uint8_t cePin, uint8_t sPin, uint8_t resetPin)
-        :LC7822(dataPin, clockPin, cePin, sPin, resetPin)
+        :LC782X(dataPin, clockPin, cePin, sPin, resetPin)
 {
-  _address = 13;
+  _address = 0x0B;
 }
 
+bool LC7821::begin(uint8_t address)
+{
+  if ((address != 0x0A) && (address != 0x0B)) return false;
+  return LC782X::begin(address);
+}
 
+
+//////////////////////////////////////////////////
+//
+//  DERIVED LC7822
+//
+LC7822::LC7822(uint8_t dataPin, uint8_t clockPin, uint8_t cePin, uint8_t sPin, uint8_t resetPin)
+        :LC782X(dataPin, clockPin, cePin, sPin, resetPin)
+{
+  _address = 0x0D;
+}
+
+bool LC7822::begin(uint8_t address)
+{
+  if ((address != 0x0C) && (address != 0x0D)) return false;
+  return LC782X::begin(address);
+}
+
+
+//////////////////////////////////////////////////
+//
+//  DERIVED LC7823
+//
 LC7823::LC7823(uint8_t dataPin, uint8_t clockPin, uint8_t cePin, uint8_t sPin, uint8_t resetPin)
-        :LC7822(dataPin, clockPin, cePin, sPin, resetPin)
+        :LC782X(dataPin, clockPin, cePin, sPin, resetPin)
+{
+  _address = 0x0F;
+}
+
+bool LC7823::begin(uint8_t address)
 {
-  _address = 15;
+  if ((address != 0x0E) && (address != 0x0F)) return false;
+  return LC782X::begin(address);
 }
 
 

libraries/LC7822/LC7822.h

@@ -3,23 +3,24 @@
 //    FILE: LC7822.h
 //  AUTHOR: Rob Tillaart
 //    DATE: 2025-12-20
-// VERSION: 0.1.0
+// VERSION: 0.2.0
 // PURPOSE: Arduino library for the LC7822 8 channel analogue switch.
 //     URL: https://github.com/RobTillaart/LC7822
 
 
 #include "Arduino.h"
 
-#define LC7822_LIB_VERSION                (F("0.1.0"))
+#define LC7822_LIB_VERSION                (F("0.2.0"))
 
 
-class LC7822
+//  base class
+class LC782X
 {
 public:
-  LC7822(uint8_t dataPin, uint8_t clockPin, uint8_t cePin,
-          uint8_t sPin, uint8_t resetPin = 255);
+  LC782X(uint8_t dataPin, uint8_t clockPin, uint8_t cePin,
+          uint8_t sPin = 255, uint8_t resetPin = 255);
 
-  bool    begin();
+  bool    begin(uint8_t address);
   bool    reset();
   uint8_t getAddress() { return _address; };
 
@@ -53,19 +54,30 @@ class LC7822
 //
 //  DERIVED
 //
-class LC7821 : public LC7822
+class LC7821 : public LC782X
 {
 public:
   LC7821(uint8_t dataPin, uint8_t clockPin, uint8_t cePin,
-          uint8_t sPin, uint8_t resetPin = 255);
+          uint8_t sPin = 255, uint8_t resetPin = 255);
+  bool begin(uint8_t address = 0x0B);
+};
+
+
+class LC7822 : public LC782X
+{
+public:
+  LC7822(uint8_t dataPin, uint8_t clockPin, uint8_t cePin,
+          uint8_t sPin = 255, uint8_t resetPin = 255);
+  bool begin(uint8_t address = 0x0D);
 };
 
 
-class LC7823 : public LC7822
+class LC7823 : public LC782X
 {
 public:
   LC7823(uint8_t dataPin, uint8_t clockPin, uint8_t cePin,
-          uint8_t sPin, uint8_t resetPin = 255);
+          uint8_t sPin = 255, uint8_t resetPin = 255);
+  bool begin(uint8_t address = 0x0F);
 };