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CommandStation-EX/IO_EXIOExpander.h

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/*
* © 2022, Peter Cole. All rights reserved.
* © 2024, Harald Barth. All rights reserved.
*
* This file is part of EX-CommandStation
*
* 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/>.
*/
/*
* The IO_EXIOExpander.h device driver integrates with one or more EX-IOExpander devices.
* This device driver will configure the device on startup, along with
* interacting with the device for all input/output duties.
*
* To create EX-IOExpander devices, these are defined in myHal.cpp:
* (Note the device driver is included by default)
*
* void halSetup() {
* // EXIOExpander::create(vpin, num_vpins, i2c_address);
* EXIOExpander::create(800, 18, 0x65);
* }
*
* All pins on an EX-IOExpander device are allocated according to the pin map for the specific
* device in use. There is no way for the device driver to sanity check pins are used for the
* correct purpose, however the EX-IOExpander device's pin map will prevent pins being used
* incorrectly (eg. A6/7 on Nano cannot be used for digital input/output).
*
* The total number of pins cannot exceed 256 because of the communications packet format.
* The number of analogue inputs cannot exceed 16 because of a limit on the maximum
* I2C packet size of 32 bytes (in the Wire library).
*/
#ifndef IO_EX_IOEXPANDER_H
#define IO_EX_IOEXPANDER_H
#include "IODevice.h"
#include "I2CManager.h"
#include "DIAG.h"
#include "FSH.h"
/////////////////////////////////////////////////////////////////////////////////////////////////////
/*
* IODevice subclass for EX-IOExpander.
*/
class EXIOExpander : public IODevice {
public:
enum ProfileType : uint8_t {
Instant = 0, // Moves immediately between positions (if duration not specified)
UseDuration = 0, // Use specified duration
Fast = 1, // Takes around 500ms end-to-end
Medium = 2, // 1 second end-to-end
Slow = 3, // 2 seconds end-to-end
Bounce = 4, // For semaphores/turnouts with a bit of bounce!!
NoPowerOff = 0x80, // Flag to be ORed in to suppress power off after move.
};
static void create(VPIN vpin, int nPins, I2CAddress i2cAddress) {
if (checkNoOverlap(vpin, nPins, i2cAddress)) new EXIOExpander(vpin, nPins, i2cAddress);
}
private:
// Constructor
EXIOExpander(VPIN firstVpin, int nPins, I2CAddress i2cAddress) {
_firstVpin = firstVpin;
// Number of pins cannot exceed 256 (1 byte) because of I2C message structure.
if (nPins > 256) nPins = 256;
_nPins = nPins;
_I2CAddress = i2cAddress;
addDevice(this);
}
void _begin() {
uint8_t status;
// Initialise EX-IOExander device
I2CManager.begin();
if (I2CManager.exists(_I2CAddress)) {
// Send config, if EXIOPINS returned, we're good, setup pin buffers, otherwise go offline
// NB The I2C calls here are done as blocking calls, as they're not time-critical
// during initialisation and the reads require waiting for a response anyway.
// Hence we can allocate I/O buffers from the stack.
uint8_t receiveBuffer[3];
uint8_t commandBuffer[4] = {EXIOINIT, (uint8_t)_nPins, (uint8_t)(_firstVpin & 0xFF), (uint8_t)(_firstVpin >> 8)};
status = I2CManager.read(_I2CAddress, receiveBuffer, sizeof(receiveBuffer), commandBuffer, sizeof(commandBuffer));
if (status == I2C_STATUS_OK) {
if (receiveBuffer[0] == EXIOPINS) {
_numDigitalPins = receiveBuffer[1];
_numAnaloguePins = receiveBuffer[2];
// See if we already have suitable buffers assigned
if (_numDigitalPins>0) {
size_t digitalBytesNeeded = (_numDigitalPins + 7) / 8;
if (_digitalPinBytes < digitalBytesNeeded) {
// Not enough space, free any existing buffer and allocate a new one
if (_digitalPinBytes > 0) free(_digitalInputStates);
if ((_digitalInputStates = (byte*) calloc(digitalBytesNeeded, 1)) != NULL) {
_digitalPinBytes = digitalBytesNeeded;
} else {
DIAG(F("EX-IOExpander I2C:%s ERROR alloc %d bytes"), _I2CAddress.toString(), digitalBytesNeeded);
_deviceState = DEVSTATE_FAILED;
_digitalPinBytes = 0;
return;
}
}
}
if (_numAnaloguePins>0) {
size_t analogueBytesNeeded = _numAnaloguePins * 2;
if (_analoguePinBytes < analogueBytesNeeded) {
// Free any existing buffers and allocate new ones.
if (_analoguePinBytes > 0) {
free(_analogueInputBuffer);
free(_analogueInputStates);
free(_analoguePinMap);
}
_analogueInputStates = (uint8_t*) calloc(analogueBytesNeeded, 1);
_analogueInputBuffer = (uint8_t*) calloc(analogueBytesNeeded, 1);
_analoguePinMap = (uint8_t*) calloc(_numAnaloguePins, 1);
if (_analogueInputStates != NULL &&
_analogueInputBuffer != NULL &&
_analoguePinMap != NULL) {
_analoguePinBytes = analogueBytesNeeded;
} else {
DIAG(F("EX-IOExpander I2C:%s ERROR alloc analog pin bytes"), _I2CAddress.toString());
_deviceState = DEVSTATE_FAILED;
_analoguePinBytes = 0;
return;
}
}
}
} else {
DIAG(F("EX-IOExpander I2C:%s ERROR configuring device"), _I2CAddress.toString());
_deviceState = DEVSTATE_FAILED;
return;
}
}
// We now need to retrieve the analogue pin map if there are analogue pins
if (status == I2C_STATUS_OK && _numAnaloguePins>0) {
commandBuffer[0] = EXIOINITA;
status = I2CManager.read(_I2CAddress, _analoguePinMap, _numAnaloguePins, commandBuffer, 1);
}
if (status == I2C_STATUS_OK) {
// Attempt to get version, if we don't get it, we don't care, don't go offline
uint8_t versionBuffer[3];
commandBuffer[0] = EXIOVER;
if (I2CManager.read(_I2CAddress, versionBuffer, sizeof(versionBuffer), commandBuffer, 1) == I2C_STATUS_OK) {
_majorVer = versionBuffer[0];
_minorVer = versionBuffer[1];
_patchVer = versionBuffer[2];
}
DIAG(F("EX-IOExpander device found, I2C:%s, Version v%d.%d.%d"),
_I2CAddress.toString(), _majorVer, _minorVer, _patchVer);
#ifdef DIAG_IO
_display();
#endif
}
if (status != I2C_STATUS_OK)
reportError(status);
} else {
DIAG(F("EX-IOExpander I2C:%s device not found"), _I2CAddress.toString());
_deviceState = DEVSTATE_FAILED;
}
}
// Digital input pin configuration, used to enable on EX-IOExpander device and set pullups if requested.
// Configuration isn't done frequently so we can use blocking I2C calls here, and so buffers can
// be allocated from the stack to reduce RAM allocation.
bool _configure(VPIN vpin, ConfigTypeEnum configType, int paramCount, int params[]) override {
if (paramCount != 1) return false;
int pin = vpin - _firstVpin;
if (configType == CONFIGURE_INPUT) {
uint8_t pullup = params[0];
uint8_t outBuffer[] = {EXIODPUP, (uint8_t)pin, pullup};
uint8_t responseBuffer[1];
uint8_t status = I2CManager.read(_I2CAddress, responseBuffer, sizeof(responseBuffer),
outBuffer, sizeof(outBuffer));
if (status == I2C_STATUS_OK) {
if (responseBuffer[0] == EXIORDY) {
return true;
} else {
DIAG(F("EXIOVpin %u cannot be used as a digital input pin"), (int)vpin);
}
} else
reportError(status);
} else if (configType == CONFIGURE_ANALOGINPUT) {
// TODO: Consider moving code from _configureAnalogIn() to here and remove _configureAnalogIn
// from IODevice class definition. Not urgent, but each virtual function defined
// means increasing the RAM requirement of every HAL device driver, whether it's relevant
// to the driver or not.
return false;
}
return false;
}
// Analogue input pin configuration, used to enable an EX-IOExpander device.
// Use I2C blocking calls and allocate buffers from stack to save RAM.
int _configureAnalogIn(VPIN vpin) override {
int pin = vpin - _firstVpin;
uint8_t commandBuffer[] = {EXIOENAN, (uint8_t)pin};
uint8_t responseBuffer[1];
uint8_t status = I2CManager.read(_I2CAddress, responseBuffer, sizeof(responseBuffer),
commandBuffer, sizeof(commandBuffer));
if (status == I2C_STATUS_OK) {
if (responseBuffer[0] == EXIORDY) {
return true;
} else {
DIAG(F("EX-IOExpander: Vpin %u cannot be used as an analogue input pin"), (int)vpin);
}
} else
reportError(status);
return false;
}
// Main loop, collect both digital and analogue pin states continuously (faster sensor/input reads)
void _loop(unsigned long currentMicros) override {
if (_deviceState == DEVSTATE_FAILED) return; // If device failed, return
// Request block is used for analogue and digital reads from the IOExpander, which are performed
// on a cyclic basis. Writes are performed synchronously as and when requested.
if (_readState != RDS_IDLE) {
if (_i2crb.isBusy()) return; // If I2C operation still in progress, return
uint8_t status = _i2crb.status;
if (status == I2C_STATUS_OK) { // If device request ok, read input data
// First check if we need to process received data
if (_readState == RDS_ANALOGUE) {
// Read of analogue values was in progress, so process received values
// Here we need to copy the values from input buffer to the analogue value array. We need to
// do this to avoid tearing of the values (i.e. one byte of a two-byte value being changed
// while the value is being read).
memcpy(_analogueInputStates, _analogueInputBuffer, _analoguePinBytes); // Copy I2C input buffer to states
} else if (_readState == RDS_DIGITAL) {
// Read of digital states was in progress, so process received values
// The received digital states are placed directly into the digital buffer on receipt,
// so don't need any further processing at this point (unless we want to check for
// changes and notify them to subscribers, to avoid the need for polling - see IO_GPIOBase.h).
}
} else
reportError(status, false); // report eror but don't go offline.
_readState = RDS_IDLE;
}
// If we're not doing anything now, check to see if a new input transfer is due.
if (_readState == RDS_IDLE) {
if (_numDigitalPins>0 && currentMicros - _lastDigitalRead > _digitalRefresh) { // Delay for digital read refresh
// Issue new read request for digital states. As the request is non-blocking, the buffer has to
// be allocated from heap (object state).
_readCommandBuffer[0] = EXIORDD;
I2CManager.read(_I2CAddress, _digitalInputStates, (_numDigitalPins+7)/8, _readCommandBuffer, 1, &_i2crb);
// non-blocking read
_lastDigitalRead = currentMicros;
_readState = RDS_DIGITAL;
} else if (_numAnaloguePins>0 && currentMicros - _lastAnalogueRead > _analogueRefresh) { // Delay for analogue read refresh
// Issue new read for analogue input states
_readCommandBuffer[0] = EXIORDAN;
I2CManager.read(_I2CAddress, _analogueInputBuffer,
_numAnaloguePins * 2, _readCommandBuffer, 1, &_i2crb);
_lastAnalogueRead = currentMicros;
_readState = RDS_ANALOGUE;
}
}
}
// Obtain the correct analogue input value, with reference to the analogue
// pin map.
// Obtain the correct analogue input value
int _readAnalogue(VPIN vpin) override {
if (_deviceState == DEVSTATE_FAILED) return 0;
int pin = vpin - _firstVpin;
for (uint8_t aPin = 0; aPin < _numAnaloguePins; aPin++) {
if (_analoguePinMap[aPin] == pin) {
uint8_t _pinLSBByte = aPin * 2;
uint8_t _pinMSBByte = _pinLSBByte + 1;
return (_analogueInputStates[_pinMSBByte] << 8) + _analogueInputStates[_pinLSBByte];
}
}
return -1; // pin not found in table
}
// Obtain the correct digital input value
int _read(VPIN vpin) override {
if (_deviceState == DEVSTATE_FAILED) return 0;
int pin = vpin - _firstVpin;
uint8_t pinByte = pin / 8;
bool value = bitRead(_digitalInputStates[pinByte], pin - pinByte * 8);
return value;
}
// Write digital value. We could have an output buffer of states, that is periodically
// written to the device if there are any changes; this would reduce the I2C overhead
// if lots of output requests are being made. We could also cache the last value
// sent so that we don't write the same value over and over to the output.
// However, for the time being, we just write the current value (blocking I2C) to the
// IOExpander node. As it is a blocking request, we can use buffers allocated from
// the stack to save RAM allocation.
void _write(VPIN vpin, int value) override {
uint8_t digitalOutBuffer[3];
uint8_t responseBuffer[1];
if (_deviceState == DEVSTATE_FAILED) return;
int pin = vpin - _firstVpin;
digitalOutBuffer[0] = EXIOWRD;
digitalOutBuffer[1] = pin;
digitalOutBuffer[2] = value;
uint8_t status = I2CManager.read(_I2CAddress, responseBuffer, 1, digitalOutBuffer, 3);
if (status != I2C_STATUS_OK) {
reportError(status);
} else {
if (responseBuffer[0] != EXIORDY) {
DIAG(F("Vpin %u cannot be used as a digital output pin"), (int)vpin);
}
}
}
// Write analogue (integer) value. Write the parameters (blocking I2C) to the
// IOExpander node. As it is a blocking request, we can use buffers allocated from
// the stack to reduce RAM allocation.
void _writeAnalogue(VPIN vpin, int value, uint8_t profile, uint16_t duration) override {
uint8_t servoBuffer[7];
uint8_t responseBuffer[1];
if (_deviceState == DEVSTATE_FAILED) return;
int pin = vpin - _firstVpin;
#ifdef DIAG_IO
DIAG(F("Servo: WriteAnalogue Vpin:%u Value:%d Profile:%d Duration:%d %S"),
vpin, value, profile, duration, _deviceState == DEVSTATE_FAILED?F("DEVSTATE_FAILED"):F(""));
#endif
servoBuffer[0] = EXIOWRAN;
servoBuffer[1] = pin;
servoBuffer[2] = value & 0xFF;
servoBuffer[3] = value >> 8;
servoBuffer[4] = profile;
servoBuffer[5] = duration & 0xFF;
servoBuffer[6] = duration >> 8;
uint8_t status = I2CManager.read(_I2CAddress, responseBuffer, 1, servoBuffer, 7);
if (status != I2C_STATUS_OK) {
DIAG(F("EX-IOExpander I2C:%s Error:%d %S"), _I2CAddress.toString(), status, I2CManager.getErrorMessage(status));
_deviceState = DEVSTATE_FAILED;
} else {
if (responseBuffer[0] != EXIORDY) {
DIAG(F("Vpin %u cannot be used as a servo/PWM pin"), (int)vpin);
}
}
}
// Display device information and status.
void _display() override {
DIAG(F("EX-IOExpander I2C:%s v%d.%d.%d Vpins %u-%u %S"),
_I2CAddress.toString(), _majorVer, _minorVer, _patchVer,
(int)_firstVpin, (int)_firstVpin+_nPins-1,
_deviceState == DEVSTATE_FAILED ? F("OFFLINE") : F(""));
}
// Helper function for error handling
void reportError(uint8_t status, bool fail=true) {
DIAG(F("EX-IOExpander I2C:%s Error:%d (%S)"), _I2CAddress.toString(),
status, I2CManager.getErrorMessage(status));
if (fail)
_deviceState = DEVSTATE_FAILED;
}
uint8_t _numDigitalPins = 0;
uint8_t _numAnaloguePins = 0;
uint8_t _majorVer = 0;
uint8_t _minorVer = 0;
uint8_t _patchVer = 0;
uint8_t* _digitalInputStates = NULL;
uint8_t* _analogueInputStates = NULL;
uint8_t* _analogueInputBuffer = NULL; // buffer for I2C input transfers
uint8_t _readCommandBuffer[1];
uint8_t _digitalPinBytes = 0; // Size of allocated memory buffer (may be longer than needed)
uint8_t _analoguePinBytes = 0; // Size of allocated memory buffer (may be longer than needed)
uint8_t* _analoguePinMap = NULL;
I2CRB _i2crb;
enum {RDS_IDLE, RDS_DIGITAL, RDS_ANALOGUE}; // Read operation states
uint8_t _readState = RDS_IDLE;
unsigned long _lastDigitalRead = 0;
unsigned long _lastAnalogueRead = 0;
const unsigned long _digitalRefresh = 10000UL; // Delay refreshing digital inputs for 10ms
const unsigned long _analogueRefresh = 50000UL; // Delay refreshing analogue inputs for 50ms
// EX-IOExpander protocol flags
enum {
EXIOINIT = 0xE0, // Flag to initialise setup procedure
EXIORDY = 0xE1, // Flag we have completed setup procedure, also for EX-IO to ACK setup
EXIODPUP = 0xE2, // Flag we're sending digital pin pullup configuration
EXIOVER = 0xE3, // Flag to get version
EXIORDAN = 0xE4, // Flag to read an analogue input
EXIOWRD = 0xE5, // Flag for digital write
EXIORDD = 0xE6, // Flag to read digital input
EXIOENAN = 0xE7, // Flag to enable an analogue pin
EXIOINITA = 0xE8, // Flag we're receiving analogue pin mappings
EXIOPINS = 0xE9, // Flag we're receiving pin counts for buffers
EXIOWRAN = 0xEA, // Flag we're sending an analogue write (PWM)
EXIOERR = 0xEF, // Flag we've received an error
};
};
#endif
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