add begin() and pullUp to PortRead_MCP23S17

doc/keybrd_library_developer_guide.md

@@ -186,6 +186,8 @@ Most derived-class names start with the base class name followed by "_" and a na
 This convention leads to class names that convey information about the classes inheritance.
 Underscore delineates base class name and sub-class name.  Capital letters delineate words.
 
+Interface class names end with "Interface".
+
 Layer-class naming conventions
 ------------------------------
 Layer classes are explained in [tutorial_3a_multi-layer_keyboard.md](../tutorials/tutorial_3a_multi-layer_keyboard.md).

src/PortRead_MCP23S17.cpp

@@ -4,18 +4,40 @@
 PortRead_MCP23S17::begin() is not needed because port direction is already configured to input by default.
 SPI bus is configured in PortWrite_MCP23S17::begin().
 */
+void PortRead_MCP23S17::begin()
+{
+    pinMode(SS, OUTPUT);                        //configure controller's Slave Select pin to output
+    digitalWrite(SS, HIGH);                     //disable Slave Select
+    SPI.begin();
+    SPI.beginTransaction(SPISettings (SPI_CLOCK_DIV8, MSBFIRST, SPI_MODE0)); //control SPI bus todo is slow clock needed?
+    digitalWrite(SS, LOW);                      //enable Slave Select
+
+      SPI.transfer(port.ADDR << 1);             //write command
+      SPI.transfer(port.num);                   //configure IODIR
+      SPI.transfer(pullUp);                     //0=output (for LED), 1=input (for read)
+
+    digitalWrite(SS, LOW);                      //enable Slave Select
+    digitalWrite(SS, HIGH);                     //disable Slave Select
+
+      SPI.transfer(port.ADDR << 1);             //write command
+      SPI.transfer(port.num + 0x0C);            //configure GPPU
+      SPI.transfer(pullUp);                     //0=pull-up disabled (for LED), 1=pull-up enabled (for read)
+
+    digitalWrite(SS, HIGH);                     //disable Slave Select
+    //SPI.endTransaction() is not called to release the SPI bus
+    // because keyboard only has one SPI device.
+}
 
 /*
-returns port value
+read() returns portState.
 */
 uint8_t PortRead_MCP23S17::read()
 {
     uint8_t portState;                          //bit wise
 
-    //slower clock
     digitalWrite(SS, LOW);                      //enable Slave Select
       SPI.transfer(port.ADDR << 1 | 1);         //read command
-      SPI.transfer(port.num + 0x12);    //register address to read data from
+      SPI.transfer(port.num + 0x12);            //GPIO register address to read data from
       portState = SPI.transfer(0);              //save the data (0 is dummy data to send)
     digitalWrite(SS, HIGH);                     //disable Slave Select
 

src/PortRead_MCP23S17.h

@@ -7,11 +7,10 @@
 #include "PortIOE.h"
 
 /* One MCP23S17 I/O expander port connected to matrix columns.
-MCP23S17 does not have internal pull-up resistors (PCA9535E does).
 
-Instantiation
+Instantiation todo
  ------------
-readPins parameter is port's bitwise pin configuration
+pullUp parameter is port's bitwise pin configuration
     1=configure as input (for pins connected to column)
     0=configure as output (for LED or not connected to a column)
 
@@ -22,18 +21,17 @@ Example instantiation for column port 1, with pins 2 and 3 connected to columns:
     PortIOE port1(1, 0);
     PortRead_MCP23S17 colPort1(port1, 2<<0 | 1<<3 );
 
-readPins are read from pin 0 on up.
+pullUp are read from pin 0 on up.
 
 */
 class PortRead_MCP23S17 : public PortRead
 {
     private:
         PortIOE& port;
+        const uint8_t pullUp;                   //bitwise, 1 means internal pull-up resistor enabled
     public:
-/*
+        PortRead_MCP23S17(PortIOE& port, const uint8_t pullUp) : port(port), pullUp(pullUp) {}
-*/
+        void begin();
-        //The constructor initialization list is in .cpp
-        PortRead_MCP23S17(PortIOE& port) : port(port) {}
         virtual uint8_t read();
 };
 #endif

src/PortWrite_MCP23S17.cpp

@@ -1,32 +1,31 @@
 #include "PortWrite_MCP23S17.h"
 
+/* writePort() sets registerAddr to data.
+*/
 void PortWrite_MCP23S17::writePort(const uint8_t registerAddr, const uint8_t data)
 {
-    //slower clock
-    //SPI.beginTransaction(SPISettings (SPI_CLOCK_DIV8, MSBFIRST, SPI_MODE0)); //control SPI bus todo move to begin()
     digitalWrite(SS, LOW);                      //enable Slave Select
       SPI.transfer(port.ADDR << 1);             //write command
       SPI.transfer(registerAddr);               //register address to write data to
       SPI.transfer(data);                       //data
     digitalWrite(SS, HIGH);                     //disable Slave Select
-    //SPI.endTransaction();               //release the SPI bus
 }    
 
-/*
+/* begin() should be called once from sketch in setup().
-If PortRead_MCP23S17 is instantiated on the same port, do NOT use PortWrite_MCP23S17::begin().
+PortRead_MCP23S17 and PortWrite_MCP23S17 should be on seperate ports on the same MCP23S17.
-Otherwise readPins could be overwritten.
 Output pins can be used for strobe pins and LEDs.
-
-SPI.endTransaction() is not called because keyboard only has one SPI device, so no need to release the SPI bus
 */
 void PortWrite_MCP23S17::begin()
 {
     pinMode(SS, OUTPUT);                        //configure controller's Slave Select pin to output
     digitalWrite(SS, HIGH);                     //disable Slave Select
     SPI.begin();
-    SPI.beginTransaction(SPISettings (SPI_CLOCK_DIV8, MSBFIRST, SPI_MODE0)); //control SPI bus
+    SPI.beginTransaction(SPISettings (SPI_CLOCK_DIV8, MSBFIRST, SPI_MODE0)); //control SPI bus todo is slow clock needed?
 
     writePort(port.num, 0);                     //configure port direction (port.num) to output (0)
+
+    //SPI.endTransaction() is not called to release the SPI bus
+    // because keyboard only has one SPI device.
 }
 
 /*

tutorials/tutorial_10_writing_IOE_Port_classes.md

@@ -16,7 +16,7 @@ To write a new Port class:
    Write very simple read and write examples for your I/O expander.
    Simple SPI I/O expander examples:
     todo link, pictures
-    /home/wolfv/Documents/Arduino/demo/IOE_MCP23S17_read/
+    /home/wolfv/Documents/Arduino/demo/IOE_MCP23S17_read/ todo internal pull-up resistors
     /home/wolfv/Documents/Arduino/demo/IOE_MCP23S17_write/
    Simple I2C I/O expander examples:
     todo link, pictures

unit_tests/PortRead_MCP23S17/PortRead_MCP23S17.ino

@@ -9,24 +9,22 @@ http://arduino.stackexchange.com/questions/28792/reading-an-mcp23s17-i-o-expande
 */
 #include "PortIOE.h"
 #include "PortRead_MCP23S17.h"
-#include "PortWrite_MCP23S17.h"
 
 const uint8_t PortIOE::ADDR = 0x20;             //MCP23S17 address, all 3 ADDR pins are grounded
 PortIOE portB(1, 0);
 
-PortRead_MCP23S17 portBRead(portB);
+PortRead_MCP23S17 portBRead(portB, ~0);
-PortWrite_MCP23S17 portBWrite(portB);           //PortBWrite needed for begin()
 
 void setup()
 {
     uint8_t portBState;                         //bit wise
 
     delay(6000);
-    portBWrite.begin();
+    portBRead.begin();
 
     portBState = portBRead.read();
     Keyboard.print("portBState = ");
-    Keyboard.println(portBState, BIN);          //should print 10101010
+    Keyboard.println(portBState, BIN);          //prints 10101010
 }
 
 void loop() { }