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add begin() and pullUp to PortRead_MCP23S17

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wolfv6 2016-09-01 01:08:52 -06:00
parent 4c082faa68
commit 5ee0cc0d65
6 changed files with 58 additions and 39 deletions
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2
doc/keybrd_library_developer_guide.md
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@ -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).

38
src/PortRead_MCP23S17.cpp
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@ -4,20 +4,42 @@
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
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
portState = SPI.transfer(0); //save the data (0 is dummy data to send)
digitalWrite(SS, HIGH); //disable Slave Select
digitalWrite(SS, LOW); //enable Slave Select
SPI.transfer(port.ADDR << 1 | 1); //read command
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
return portState;
}

14
src/PortRead_MCP23S17.h
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@ -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:
/*
*/
//The constructor initialization list is in .cpp
PortRead_MCP23S17(PortIOE& port) : port(port) {}
PortRead_MCP23S17(PortIOE& port, const uint8_t pullUp) : port(port), pullUp(pullUp) {}
void begin();
virtual uint8_t read();
};
#endif

33
src/PortWrite_MCP23S17.cpp
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@ -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
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
}
/*
If PortRead_MCP23S17 is instantiated on the same port, do NOT use PortWrite_MCP23S17::begin().
Otherwise readPins could be overwritten.
/* begin() should be called once from sketch in setup().
PortRead_MCP23S17 and PortWrite_MCP23S17 should be on seperate ports on the same MCP23S17.
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
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)
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.
}
/*

2
tutorials/tutorial_10_writing_IOE_Port_classes.md
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@ -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

8
unit_tests/PortRead_MCP23S17/PortRead_MCP23S17.ino
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@ -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);
PortWrite_MCP23S17 portBWrite(portB); //PortBWrite needed for begin()
PortRead_MCP23S17 portBRead(portB, ~0);
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() { }