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CommandStation-EX/IO_GPIOBase.h

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/*
* © 2021, Neil McKechnie. All rights reserved.
*
* This file is part of DCC++EX API
*
* This is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* It is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with CommandStation. If not, see <https://www.gnu.org/licenses/>.
*/
#ifndef IO_GPIOBASE_H
#define IO_GPIOBASE_H
#include "IODevice.h"
#include "I2CManager.h"
#include "DIAG.h"
// GPIOBase is defined as a class template. This allows it to be instantiated by
// subclasses with different types, according to the number of pins on the GPIO module.
// For example, GPIOBase<uint8_t> for 8 pins, GPIOBase<uint16_t> for 16 pins etc.
// A module with up to 64 pins can be handled in this way (uint64_t).
template <class T>
class GPIOBase : public IODevice {
protected:
// Constructor
GPIOBase(FSH *deviceName, VPIN firstVpin, uint8_t nPins, I2CAddress i2cAddress, int interruptPin);
// Device-specific initialisation
void _begin() override;
// Device-specific pin configuration function.
bool _configure(VPIN vpin, ConfigTypeEnum configType, int paramCount, int params[]) override;
// Pin write function.
void _write(VPIN vpin, int value) override;
// Pin read function.
int _read(VPIN vpin) override;
void _display() override;
void _loop(unsigned long currentMicros) override;
// Data fields
// Allocate enough space for all input pins
T _portInputState; // 1=high (inactive), 0=low (activated)
T _portOutputState; // 1 =high, 0=low
T _portMode; // 0=input, 1=output
T _portPullup; // 0=nopullup, 1=pullup
T _portInUse; // 0=not in use, 1=in use
// Target interval between refreshes of each input port
static const int _portTickTime = 4000; // 4ms
// Virtual functions for interfacing with I2C GPIO Device
virtual void _writeGpioPort() = 0;
virtual void _readGpioPort(bool immediate=true) = 0;
virtual void _writePullups() {};
virtual void _writePortModes() {};
virtual void _setupDevice() {};
virtual void _processCompletion(uint8_t status) {
(void)status; // Suppress compiler warning
};
I2CRB requestBlock;
FSH *_deviceName;
};
// Because class GPIOBase is a template, the implementation (below) must be contained within the same
// file as the class declaration (above). Otherwise it won't compile!
// Constructor
template <class T>
GPIOBase<T>::GPIOBase(FSH *deviceName, VPIN firstVpin, uint8_t nPins, I2CAddress i2cAddress, int interruptPin) :
IODevice(firstVpin, nPins)
{
if (_nPins > (int)sizeof(T)*8) _nPins = sizeof(T)*8; // Ensure nPins is consistent with the number of bits in T
_deviceName = deviceName;
_I2CAddress = i2cAddress;
_gpioInterruptPin = interruptPin;
_hasCallback = true;
// Add device to list of devices.
addDevice(this);
_portMode = 0; // default to input mode
_portPullup = -1; // default to pullup enabled
_portInputState = -1; // default to all inputs high (inactive)
_portInUse = 0; // No ports in use initially.
}
template <class T>
void GPIOBase<T>::_begin() {
// Configure pin used for GPIO extender notification of change (if allocated)
if (_gpioInterruptPin >= 0)
pinMode(_gpioInterruptPin, INPUT_PULLUP);
I2CManager.begin();
I2CManager.setClock(400000);
if (I2CManager.exists(_I2CAddress)) {
#if defined(DIAG_IO)
_display();
#endif
_setupDevice();
_deviceState = DEVSTATE_NORMAL;
} else {
DIAG(F("%S I2C:%s Device not detected"), _deviceName, _I2CAddress.toString());
_deviceState = DEVSTATE_FAILED;
}
}
// Configuration parameters for inputs:
// params[0]: enable pullup
template <class T>
bool GPIOBase<T>::_configure(VPIN vpin, ConfigTypeEnum configType, int paramCount, int params[]) {
if (configType != CONFIGURE_INPUT) return false;
if (paramCount == 0 || paramCount > 1) return false;
bool pullup = params[0];
int pin = vpin - _firstVpin;
#ifdef DIAG_IO
DIAG(F("%S I2C:%s Config Pin:%d Val:%d"), _deviceName, _I2CAddress.toString(), pin, pullup);
#endif
uint16_t mask = 1 << pin;
if (pullup)
_portPullup |= mask;
else
_portPullup &= ~mask;
// Mark that port has been accessed
_portInUse |= mask;
// Set input mode
_portMode &= ~mask;
// Call subclass's virtual function to write to device
_writePortModes();
_writePullups();
// Port change will be notified on next loop entry.
return true;
}
// Periodically read the input port
template <class T>
void GPIOBase<T>::_loop(unsigned long currentMicros) {
T lastPortStates = _portInputState;
if (_deviceState == DEVSTATE_SCANNING && !requestBlock.isBusy()) {
uint8_t status = requestBlock.status;
if (status == I2C_STATUS_OK) {
_deviceState = DEVSTATE_NORMAL;
} else {
_deviceState = DEVSTATE_FAILED;
DIAG(F("%S I2C:%s Error:%d %S"), _deviceName, _I2CAddress.toString(), status,
I2CManager.getErrorMessage(status));
}
_processCompletion(status);
// Set unused pin and write mode pin value to 1
_portInputState |= ~_portInUse | _portMode;
// Scan for changes in input states and invoke callback (if present)
T differences = lastPortStates ^ _portInputState;
if (differences && IONotifyCallback::hasCallback()) {
// Scan for differences bit by bit
T mask = 1;
for (int pin=0; pin<_nPins; pin++) {
if (differences & mask) {
// Change detected.
IONotifyCallback::invokeAll(_firstVpin+pin, (_portInputState & mask) == 0);
}
mask <<= 1;
}
}
#ifdef DIAG_IO
if (differences)
DIAG(F("%S I2C:%s PortStates:%x"), _deviceName, _I2CAddress.toString(), _portInputState);
#endif
}
// Check if interrupt configured. If not, or if it is active (pulled down), then
// initiate a scan.
if (_gpioInterruptPin < 0 || !digitalRead(_gpioInterruptPin)) {
// TODO: Could suppress reads if there are no pins configured as inputs!
// Read input
if (_deviceState == DEVSTATE_NORMAL) {
_readGpioPort(false); // Initiate non-blocking read
_deviceState= DEVSTATE_SCANNING;
}
}
// Delay next entry until tick elapsed.
delayUntil(currentMicros + _portTickTime);
}
template <class T>
void GPIOBase<T>::_display() {
DIAG(F("%S I2C:%s Configured on Vpins:%u-%u %S"), _deviceName, _I2CAddress.toString(),
_firstVpin, _firstVpin+_nPins-1, (_deviceState==DEVSTATE_FAILED) ? F("OFFLINE") : F(""));
}
template <class T>
void GPIOBase<T>::_write(VPIN vpin, int value) {
int pin = vpin - _firstVpin;
T mask = 1 << pin;
#ifdef DIAG_IO
DIAG(F("%S I2C:%s Write Pin:%d Val:%d"), _deviceName, _I2CAddress.toString(), pin, value);
#endif
// Set port mode output if currently not output mode
if (!(_portMode & mask)) {
_portInUse |= mask;
_portMode |= mask;
_writePortModes();
}
// Update port output state
if (value)
_portOutputState |= mask;
else
_portOutputState &= ~mask;
// Call subclass's virtual function to write to device.
return _writeGpioPort();
}
template <class T>
int GPIOBase<T>::_read(VPIN vpin) {
int pin = vpin - _firstVpin;
T mask = 1 << pin;
// Set port mode to input if currently output or first use
if ((_portMode | ~_portInUse) & mask) {
_portMode &= ~mask;
_portInUse |= mask;
_writePullups();
_writePortModes();
// Port won't have been read yet, so read it now.
_readGpioPort();
// Set unused pin and write mode pin value to 1
_portInputState |= ~_portInUse | _portMode;
#ifdef DIAG_IO
DIAG(F("%S I2C:%s PortStates:%x"), _deviceName, _I2CAddress.toString(), _portInputState);
#endif
}
return (_portInputState & mask) ? 0 : 1; // Invert state (5v=0, 0v=1)
}
#endif
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