mirror of
https://github.com/DCC-EX/CommandStation-EX.git
synced 2024-11-22 15:46:14 +01:00
235 lines
8.9 KiB
C
235 lines
8.9 KiB
C
/*
|
|
* © 2023, Neil McKechnie. All rights reserved.
|
|
*
|
|
* This file is part of CommandStation-EX
|
|
*
|
|
* 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 I2CMANAGER_WIRE_H
|
|
#define I2CMANAGER_WIRE_H
|
|
|
|
#include <Arduino.h>
|
|
#include <Wire.h>
|
|
#include "I2CManager.h"
|
|
|
|
// This module is only compiled if I2C_USE_WIRE is defined, so define it here
|
|
// to get intellisense to work correctly.
|
|
#if !defined(I2C_USE_WIRE)
|
|
#define I2C_USE_WIRE
|
|
#endif
|
|
|
|
// Older versions of Wire don't have setWireTimeout function. AVR does.
|
|
#ifdef ARDUINO_ARCH_AVR
|
|
#define WIRE_HAS_TIMEOUT
|
|
#endif
|
|
|
|
/***************************************************************************
|
|
* Initialise I2C interface software
|
|
***************************************************************************/
|
|
void I2CManagerClass::_initialise() {
|
|
Wire.begin();
|
|
#if defined(WIRE_HAS_TIMEOUT)
|
|
Wire.setWireTimeout(_timeout, true);
|
|
#endif
|
|
}
|
|
|
|
/***************************************************************************
|
|
* Set I2C clock speed. Normally 100000 (Standard) or 400000 (Fast)
|
|
* on Arduino. Mega4809 supports 1000000 (Fast+) too.
|
|
***************************************************************************/
|
|
void I2CManagerClass::_setClock(unsigned long i2cClockSpeed) {
|
|
Wire.setClock(i2cClockSpeed);
|
|
}
|
|
|
|
/***************************************************************************
|
|
* Set I2C timeout value in microseconds. The timeout applies to each
|
|
* Wire call separately, i.e. in a write+read, the timer is reset before the
|
|
* read is started.
|
|
***************************************************************************/
|
|
void I2CManagerClass::setTimeout(unsigned long value) {
|
|
_timeout = value;
|
|
#if defined(WIRE_HAS_TIMEOUT)
|
|
Wire.setWireTimeout(value, true);
|
|
#endif
|
|
}
|
|
|
|
/********************************************************
|
|
* Helper function for I2C Multiplexer operations
|
|
********************************************************/
|
|
#ifdef I2C_EXTENDED_ADDRESS
|
|
static uint8_t muxSelect(I2CAddress address) {
|
|
// Select MUX sub bus.
|
|
I2CMux muxNo = address.muxNumber();
|
|
I2CSubBus subBus = address.subBus();
|
|
if (muxNo != I2CMux_None) {
|
|
Wire.beginTransmission(I2C_MUX_BASE_ADDRESS+muxNo);
|
|
uint8_t data = (subBus == SubBus_All) ? 0xff :
|
|
(subBus == SubBus_None) ? 0x00 :
|
|
#if defined(I2CMUX_PCA9547)
|
|
0x08 | subBus;
|
|
#elif defined(I2CMUX_PCA9542) || defined(I2CMUX_PCA9544)
|
|
0x04 | subBus; // NB Only 2 or 4 subbuses respectively
|
|
#else
|
|
// Default behaviour for most MUXs is to use a mask
|
|
// with a bit set for the subBus to be enabled
|
|
1 << subBus;
|
|
#endif
|
|
Wire.write(&data, 1);
|
|
return Wire.endTransmission(true); // have to release I2C bus for it to work
|
|
}
|
|
return I2C_STATUS_OK;
|
|
}
|
|
#endif
|
|
|
|
|
|
/***************************************************************************
|
|
* Initiate a write to an I2C device (blocking operation on Wire)
|
|
***************************************************************************/
|
|
uint8_t I2CManagerClass::write(I2CAddress address, const uint8_t buffer[], uint8_t size, I2CRB *rb) {
|
|
uint8_t status, muxStatus;
|
|
uint8_t retryCount = 0;
|
|
// If request fails, retry up to the defined limit, unless the NORETRY flag is set
|
|
// in the request block.
|
|
do {
|
|
status = muxStatus = I2C_STATUS_OK;
|
|
#ifdef I2C_EXTENDED_ADDRESS
|
|
if (address.muxNumber() != I2CMux_None)
|
|
muxStatus = muxSelect(address);
|
|
#endif
|
|
// Only send new transaction if address is non-zero.
|
|
if (muxStatus == I2C_STATUS_OK && address != 0) {
|
|
Wire.beginTransmission(address);
|
|
if (size > 0) Wire.write(buffer, size);
|
|
status = Wire.endTransmission();
|
|
}
|
|
#ifdef I2C_EXTENDED_ADDRESS
|
|
// Deselect MUX if there's more than one MUX present, to avoid having multiple ones selected
|
|
if (_muxCount > 1 && muxStatus == I2C_STATUS_OK
|
|
&& address.deviceAddress() != 0 && address.muxNumber() != I2CMux_None) {
|
|
muxSelect({address.muxNumber(), SubBus_None});
|
|
}
|
|
if (muxStatus != I2C_STATUS_OK) status = muxStatus;
|
|
#endif
|
|
} while (!(status == I2C_STATUS_OK
|
|
|| ++retryCount > MAX_I2C_RETRIES || rb->operation & OPERATION_NORETRY));
|
|
rb->status = status;
|
|
return I2C_STATUS_OK;
|
|
}
|
|
|
|
/***************************************************************************
|
|
* Initiate a write from PROGMEM (flash) to an I2C device (blocking operation on Wire)
|
|
***************************************************************************/
|
|
uint8_t I2CManagerClass::write_P(I2CAddress address, const uint8_t buffer[], uint8_t size, I2CRB *rb) {
|
|
uint8_t ramBuffer[size];
|
|
const uint8_t *p1 = buffer;
|
|
for (uint8_t i=0; i<size; i++)
|
|
ramBuffer[i] = GETFLASH(p1++);
|
|
return write(address, ramBuffer, size, rb);
|
|
}
|
|
|
|
/***************************************************************************
|
|
* Initiate a write (optional) followed by a read from the I2C device (blocking operation on Wire)
|
|
* If fewer than the number of requested bytes are received, status is I2C_STATUS_TRUNCATED.
|
|
***************************************************************************/
|
|
uint8_t I2CManagerClass::read(I2CAddress address, uint8_t readBuffer[], uint8_t readSize,
|
|
const uint8_t writeBuffer[], uint8_t writeSize, I2CRB *rb)
|
|
{
|
|
uint8_t status, muxStatus;
|
|
uint8_t nBytes = 0;
|
|
uint8_t retryCount = 0;
|
|
// If request fails, retry up to the defined limit, unless the NORETRY flag is set
|
|
// in the request block.
|
|
do {
|
|
status = muxStatus = I2C_STATUS_OK;
|
|
#ifdef I2C_EXTENDED_ADDRESS
|
|
if (address.muxNumber() != I2CMux_None) {
|
|
muxStatus = muxSelect(address);
|
|
}
|
|
#endif
|
|
// Only start new transaction if address is non-zero.
|
|
if (muxStatus == I2C_STATUS_OK && address != 0) {
|
|
if (writeSize > 0) {
|
|
Wire.beginTransmission(address);
|
|
Wire.write(writeBuffer, writeSize);
|
|
status = Wire.endTransmission(false); // Don't free bus yet
|
|
}
|
|
if (status == I2C_STATUS_OK) {
|
|
#ifdef WIRE_HAS_TIMEOUT
|
|
Wire.clearWireTimeoutFlag();
|
|
Wire.requestFrom(address, (size_t)readSize);
|
|
if (!Wire.getWireTimeoutFlag()) {
|
|
while (Wire.available() && nBytes < readSize)
|
|
readBuffer[nBytes++] = Wire.read();
|
|
if (nBytes < readSize) status = I2C_STATUS_TRUNCATED;
|
|
} else {
|
|
status = I2C_STATUS_TIMEOUT;
|
|
}
|
|
#else
|
|
Wire.requestFrom(address, (size_t)readSize);
|
|
while (Wire.available() && nBytes < readSize)
|
|
readBuffer[nBytes++] = Wire.read();
|
|
if (nBytes < readSize) status = I2C_STATUS_TRUNCATED;
|
|
#endif
|
|
}
|
|
}
|
|
#ifdef I2C_EXTENDED_ADDRESS
|
|
// Deselect MUX if there's more than one MUX present, to avoid having multiple ones selected
|
|
if (_muxCount > 1 && muxStatus == I2C_STATUS_OK && address != 0 && address.muxNumber() != I2CMux_None) {
|
|
muxSelect({address.muxNumber(), SubBus_None});
|
|
}
|
|
if (muxStatus != I2C_STATUS_OK) status = muxStatus;
|
|
#endif
|
|
|
|
} while (!((status == I2C_STATUS_OK)
|
|
|| ++retryCount > MAX_I2C_RETRIES || rb->operation & OPERATION_NORETRY));
|
|
|
|
rb->nBytes = nBytes;
|
|
rb->status = status;
|
|
return I2C_STATUS_OK;
|
|
}
|
|
|
|
|
|
/***************************************************************************
|
|
* Function to queue a request block and initiate operations.
|
|
*
|
|
* For the Wire version, this executes synchronously.
|
|
* The read/write/write_P functions return I2C_STATUS_OK always, and the
|
|
* completion status of the operation is in the request block, as for
|
|
* the non-blocking version.
|
|
***************************************************************************/
|
|
void I2CManagerClass::queueRequest(I2CRB *req) {
|
|
switch (req->operation & OPERATION_MASK) {
|
|
case OPERATION_READ:
|
|
read(req->i2cAddress, req->readBuffer, req->readLen, NULL, 0, req);
|
|
break;
|
|
case OPERATION_SEND:
|
|
write(req->i2cAddress, req->writeBuffer, req->writeLen, req);
|
|
break;
|
|
case OPERATION_SEND_P:
|
|
write_P(req->i2cAddress, req->writeBuffer, req->writeLen, req);
|
|
break;
|
|
case OPERATION_REQUEST:
|
|
read(req->i2cAddress, req->readBuffer, req->readLen, req->writeBuffer, req->writeLen, req);
|
|
break;
|
|
}
|
|
}
|
|
|
|
/***************************************************************************
|
|
* Loop function, for general background work
|
|
***************************************************************************/
|
|
void I2CManagerClass::loop() {}
|
|
|
|
#endif
|