add refPortWrite.begin(strobeOn) to Scanner_IOE::begin(), update unit tests

src/PortMCP23S17.cpp

@@ -22,6 +22,9 @@ strobeOn is logic level of strobe on, HIGH or LOW
 MCP23S17 SPI interface is 10 MHz max.
 The electrical limitation to bus speed is bus capacitance and the length of the wires involved.
 Longer wires require lower clock speeds. 
+
+begin() is called from Scanner_IOE::begin() twice, once each for refPortWrite and refPortRead.
+The first 4 lines only need to be called once, but seem to work OK if called a second time.
 */
 void PortMCP23S17::begin(const uint8_t strobeOn)
 {
@@ -41,10 +44,6 @@ void PortMCP23S17::begin(const uint8_t strobeOn)
     {
         pullUp = 0;
     }
-//todo
-Keyboard.print(" strobeOn="); Keyboard.print(strobeOn);
-Keyboard.print(" readPins="); Keyboard.print(readPins, BIN);
-Keyboard.print(" pullUp="); Keyboard.println(pullUp, BIN);
 
     transfer(port.DEVICE_ADDR << 1, port.num, readPins); //configure IODIR
     transfer(port.DEVICE_ADDR << 1, port.num + 0x0C, pullUp); //configure GPPU
@@ -65,13 +64,6 @@ void PortMCP23S17::write(const uint8_t pin, const bool logicLevel)
     {
         port.outputVal |= pin;                  //set pin output to high
     }
-//todo
-//Keyboard.print(" readPins="); Keyboard.print(readPins, BIN);
-Keyboard.print(" pin="); Keyboard.print(pin, BIN);
-Keyboard.print(" logicLevel="); Keyboard.print(logicLevel);
-Keyboard.print(" outputVal="); Keyboard.println(port.outputVal, BIN);
-//Keyboard.print(" ="); Keyboard.print();
-//delay(200);
 
     transfer(port.DEVICE_ADDR << 1, port.num + 0x12, port.outputVal); //set GPIO port to outputVal
 }

src/Scanner_IOE.cpp

@@ -13,6 +13,7 @@ Initiates communication protocal and configs ports.
 void Scanner_IOE::begin()
 {
     refPortRead.begin(strobeOn);
+    refPortWrite.begin(strobeOn);
 }
 
 /* scan() is called on every iteration of sketch loop().
@@ -23,13 +24,10 @@ read_pins_t Scanner_IOE::scan(const uint8_t strobePin)
 {
     uint8_t readState;                          //bits, 1 means key is pressed, 0 means released
 
-delay(2000);//todo
     //strobe on
     refPortWrite.write(strobePin, strobeOn);
     delayMicroseconds(3);                       //time to stabilize voltage
-    //delayMicroseconds(300);                     //todo
 
-delay(2000);
     //read the port pins
     readState = refPortRead.read();
 

unit_tests/PortMCP23S17_read/PortMCP23S17_read.ino

@@ -1,5 +1,5 @@
-/* unit test for PortRead_MCP23S17
-Picture of hardware is in unit_tests/PortRead_MCP23S17/PortRead_MCP23S17_bb.JPG
+/* unit test for PortMCP23S17
+Picture of hardware is in unit_tests/PortMCP23S17_read/PortMCP23S17_bb.JPG
 The setup is an MCP23S17 I/O expander on a Teensy LC controller.
 MCP23S17 port-B pins are alternately grounded and energized.
 portBState is a bitwise reading of port B.
@@ -7,20 +7,19 @@ output is: 10101010
 */
 
 #include "PortIOE.h"
-#include "PortRead_MCP23S17.h"
-#include "Scanner_IOE.h"
+#include "PortMCP23S17.h"
 
 const uint8_t PortIOE::DEVICE_ADDR = 0x20;      //MCP23S17 address, all 3 ADDR pins are grounded
-PortIOE portB(1, 0);
+PortIOE portB(1);
 
-PortRead_MCP23S17 portBRead(portB, ~0);
+PortMCP23S17 portBRead(portB, ~0);
 
 void setup()
 {
     uint8_t portBState;                         //bit pattern
 
     delay(6000);
-    portBRead.begin(LOW);
+    portBRead.begin(HIGH);                      //HIGH or LOW, not matter
 
     portBState = portBRead.read();
     Keyboard.print("portBState = ");

unit_tests/PortMCP23S17_write/PortMCP23S17_write.ino

@@ -1,29 +1,27 @@
-/* unit test for PortWrite_MCP23S17
-Picture of hardware is in unit_tests/PortRead_MCP23S17/PortRead_MCP23S17_bb.JPG
+/* unit test for PortMCP23S17
+Picture of hardware is in unit_tests/PortMCP23S17_read/PortMCP23S17_bb.JPG
 The setup is an MCP23S17 I/O expander on a Teensy LC controller.
 MCP23S17 port-A GPIO pins are not connected to anything.
 Port-A GPIO-pin ouputs alternate between 0 and 3.3 volts.
 
 Use a volt meter to measure port-A GPIO-pin outputs.
-MCP23S17 on 3.3v does not output enough power to reliable light LEDs
-    LED lights w/o resistor
-    LED not light with 56 ohm resistor
+OR low-voltage LED, with forward voltage less than 2 volts.
 */
 #include "PortIOE.h"
-#include "PortWrite_MCP23S17.h"
+#include "PortMCP23S17.h"
 
 const uint8_t PortIOE::DEVICE_ADDR = 0x20;      //MCP23S17 address, all 3 ADDR pins are grounded
-PortIOE portA(0, 0);
+PortIOE portA(0);
 
-PortWrite_MCP23S17 portAWrite(portA);           //PortAWrite needed for begin()
+PortMCP23S17 portAWrite(portA, 0);              //PortAWrite needed for begin()
 
 //const uint8_t GPIOA = 0x12;                     //LEDs are on port A
 
 void setup()
 {
     delay(6000);
-    portAWrite.begin();
-    //Keyboard.print("start blinking");
+    portAWrite.begin(LOW);                     //HIGH or LOW, not matter if readPins=0
+    Keyboard.print("start writing");
 }
 
 void loop()