0.1.1 MCP23008

libraries/MCP23008/MCP23008.cpp

@@ -1,13 +1,14 @@
 //
 //    FILE: MCP23008.cpp
 //  AUTHOR: Rob Tillaart
-// VERSION: 0.1.0
+// VERSION: 0.1.1
 // PURPOSE: Arduino library for I2C MCP23008 8 channel port expander
 //    DATE: 2019-10-12
 //     URL: https://github.com/RobTillaart/MCP23008
 //
 //  HISTORY:
 //  0.1.0   2022-01-10  initial version
+//  0.1.1   2022-09-28  optimize digitalWrite() [as that is the most used one]
 
 
 
@@ -131,6 +132,7 @@ bool MCP23008::digitalWrite(uint8_t pin, uint8_t value)
   }
   uint8_t IOR = MCP23008_GPIO_A;
   uint8_t val = readReg(IOR);
+  uint8_t pre = val;
   if (_error != MCP23008_OK)
   {
     return false;
@@ -145,11 +147,15 @@ bool MCP23008::digitalWrite(uint8_t pin, uint8_t value)
   {
     val &= ~mask;
   }
+  //  only write if there is a change
+  if (val != pre)
+  {
     writeReg(IOR, val);
     if (_error != MCP23008_OK)
     {
       return false;
     }
+  }
   return true;
 }
 
@@ -278,6 +284,7 @@ bool MCP23008::getPullup(uint8_t pin, bool &pullup)
 
 
 ///////////////////////////////////////////////////////////////////////
+//
 //  8 pins interface
 //  whole register at once
 //  value = 0..0xFF  bit pattern

libraries/MCP23008/MCP23008.h

@@ -2,7 +2,7 @@
 //
 //    FILE: MCP23008.h
 //  AUTHOR: Rob Tillaart
-// VERSION: 0.1.0
+// VERSION: 0.1.1
 // PURPOSE: Arduino library for I2C MCP23008 16 channel port expander
 //    DATE: 2022-01-10
 //     URL: https://github.com/RobTillaart/MCP23008
@@ -12,7 +12,7 @@
 #include "Wire.h"
 
 
-#define MCP23008_LIB_VERSION              (F("0.1.0"))
+#define MCP23008_LIB_VERSION              (F("0.1.1"))
 
 #define MCP23008_OK                       0x00
 #define MCP23008_PIN_ERROR                0x81

libraries/MCP23008/README.md

@@ -18,6 +18,9 @@ This library gives easy control over the 8 pins of a (I2C) MCP23008 chip.
 This IC is strongly related tot the MCP23017 I2C port expander - https://github.com/RobTillaart/MCP23017_RT
 Programming Interface is kept the same as much as possible.
 
+Since 0.1.1 the **digitalWrite(pin, value)** is optimized. 
+If a pin is not changed it will not be written again to save time.
+
 
 ## Interface
 
@@ -32,28 +35,30 @@ Can be overruled with Wire0..WireN.
 
 ### Single pin interface
 
-- **bool pinMode(uint8_t pin, uint8_t mode)** pin = 0..7, mode = INPUT, OUTPUT, returns true if successful.
-- **bool digitalWrite(uint8_t pin, uint8_t value)** pin = 0..7, value = LOW(0) HIGH (!0), returns true if successful.
+- **bool pinMode(uint8_t pin, uint8_t mode)** pin = 0..7, mode = INPUT, OUTPUT. Returns true if successful.
+- **bool digitalWrite(uint8_t pin, uint8_t value)** pin = 0..7, value = LOW(0) HIGH (!0). Returns true if successful.
 - **uint8_t digitalRead(uint8_t pin)** pin = 0..7, returns LOW or HIGH, might set the lastError();
-- **bool setPolarity(uint8_t pin, bool reversed)** pin = 0..7, set reversed flag, returns true if successful.
-- **bool getPolarity(uint8_t pin, bool &reversed)** pin = 0..7, reads reversed flag, returns true if successful.
-- **bool setPullup(uint8_t pin, bool pullup)** pin = 0..7, set pull-up flag, returns true if successful.
-- **bool getPullup(uint8_t pin, bool &pullup)** pin = 0..7, reads pull-up flag, returns true if successful.
+- **bool setPolarity(uint8_t pin, bool reversed)** pin = 0..7, set reversed flag. Returns true if successful.
+- **bool getPolarity(uint8_t pin, bool &reversed)** pin = 0..7, reads reversed flag. Returns true if successful.
+- **bool setPullup(uint8_t pin, bool pullup)** pin = 0..7, set pull-up flag. Returns true if successful.
+- **bool getPullup(uint8_t pin, bool &pullup)** pin = 0..7, reads pull-up flag. Returns true if successful.
 
 
 ### 8 pins interface
 
-- **bool pinMode8(uint8_t value)** value = 0..255, returns true if successful.
-- **bool write8(uint8_t value)** value = 0..255, returns true if successful.
+- **bool pinMode8(uint8_t value)** value = 0..255. Returns true if successful.
+- **bool write8(uint8_t value)** value = 0..255. Returns true if successful.
 - **uint8_t read8()** reads 8 pins into one byte.
-- **bool setPolarity8(uint8_t mask)** sets polarity for 8 channels at once.
-- **bool getPolarity8(uint8_t &mask)** reads polarity of 8 channels at once.
-- **bool setPullup8(uint8_t mask)** sets pull-up for 8 channels at once.
-- **bool getPullup8(uint8_t &mask)** reads pull-up for 8 channels at once.
+- **bool setPolarity8(uint8_t mask)** sets polarity for 8 channels at once. Returns true if successful.
+- **bool getPolarity8(uint8_t &mask)** reads polarity of 8 channels at once. Returns true if successful.
+- **bool setPullup8(uint8_t mask)** sets pull-up for 8 channels at once. Returns true if successful.
+- **bool getPullup8(uint8_t &mask)** reads pull-up for 8 channels at once. Returns true if successful.
 
 
 ### Error codes
 
+If one of the above functions return false, there might be an error.
+
 - **int lastError()** Above functions set an error flag that can be read with this function.  
 Reading it will reset the flag to **MCP23008_OK**.
 

libraries/MCP23008/examples/MCP23008_I2C_Keypad_4x4_read/MCP23008_I2C_Keypad_4x4_read.ino

@@ -0,0 +1,88 @@
+
+//
+//    FILE: MCP23008_I2C_Keypad_4x4_read.ino
+//  AUTHOR: François Longchamp
+//    DATE: 2022-09-27
+// PUPROSE: Keypad MCP23008 library
+//
+// Tested with Seeed Studio XIAO RP2040
+// Keypad used https://fr.aliexpress.com/item/1005003176287473.html
+
+
+#include "MCP23008.h"
+#include "Wire.h"
+
+
+MCP23008 MCP(0x20);
+
+const byte ROWS_OF_KEYPAD = 4; //four rows
+const byte COLS_OF_KEYPAD = 4; //four columns
+byte keys_of_keypad[ROWS_OF_KEYPAD][COLS_OF_KEYPAD] = {
+  {1, 2, 3, 4},
+  {5, 6, 7, 8},
+  {9, 10,11,12},
+  {13,14,15,16}
+};
+
+
+void setup()
+{
+  Serial.begin(115200);
+  Serial.print("MCP23008 version: ");
+  Serial.println(MCP23008_LIB_VERSION);
+
+  Wire.begin();
+  MCP.begin();
+
+}
+
+void loop()
+{
+  bool val;
+
+  // rows pinMode (0 or false = pressed)
+  MCP.pinMode8(0x0f);
+  for (int pin = 0; pin < 4; pin++)
+  {
+
+    val = MCP.digitalRead(pin);
+    Serial.print(val);
+    Serial.print(' ');
+  }
+
+  // columns pinMode (0 or false = pressed)
+  MCP.pinMode8(0xf0);
+  for (int pin = 4; pin < 8; pin++)
+  {
+
+    val = MCP.digitalRead(pin);
+    Serial.print(val);
+    Serial.print(' ');
+  }
+
+  // digital pressed from referer keys_of_keypad
+  MCP.pinMode8(0x0f);
+  for (int r = 0; r < ROWS_OF_KEYPAD; r++)
+  {
+
+    if( MCP.digitalRead(r) == false ) // false = pressed
+    {
+
+      MCP.pinMode8(0xf0);
+      for (int c = ROWS_OF_KEYPAD; c < ROWS_OF_KEYPAD+COLS_OF_KEYPAD; c++)
+      {
+
+        if( MCP.digitalRead(c) == false ) // false = pressed
+        {
+
+          Serial.print(keys_of_keypad[r][c-4]);
+        }
+      }
+
+      MCP.pinMode8(0x0f);
+    }
+  }
+
+  Serial.println("");
+  delay(500);
+}

libraries/MCP23008/examples/MCP23008_performance/MCP23008_performance.ino

@@ -24,6 +24,8 @@ void setup()
 
   Wire.begin();
   bool b = MCP.begin();
+  Serial.print("BEGIN: ");
+  Serial.println(b);
 
   MCP.pinMode8(0x00);  // 0 = output , 1 = input
 
@@ -55,13 +57,15 @@ void setup()
 
   Serial.print("TEST digitalRead(pin):\t");
   delay(100);
+  volatile int val = 0;
   start = micros();
   for (int pin = 0; pin < 8; pin++)
   {
-    volatile int val = MCP.digitalRead(pin);
+    val = MCP.digitalRead(pin);
   }
   stop = micros();
   Serial.println((stop - start) / 8.0);
+  Serial.println(val);
   Serial.println();
 
 
@@ -83,6 +87,7 @@ void setup()
   volatile int val8 = MCP.read8();
   stop = micros();
   Serial.println(stop - start);
+  Serial.println(val8);
   Serial.println();
 
   Serial.println("\ndone...");

libraries/MCP23008/library.json

@@ -15,7 +15,7 @@
     "type": "git",
     "url": "https://github.com/RobTillaart/MCP23008.git"
   },
-  "version": "0.1.0",
+  "version": "0.1.1",
   "license": "MIT",
   "frameworks": "arduino",
   "platforms": "*",

libraries/MCP23008/library.properties

@@ -1,5 +1,5 @@
 name=MCP23008
-version=0.1.0
+version=0.1.1
 author=Rob Tillaart <rob.tillaart@gmail.com>
 maintainer=Rob Tillaart <rob.tillaart@gmail.com>
 sentence=Arduino library for I2C MCP23008 8 channel port expander  8 IO-lines