firmware.ino File Reference

Firmware for an I2C slave controlling up to 8 stepper motors with the AccelStepper library, comes with the matching AccelStepperI2C library. More...

Detailed Description

Firmware for an I2C slave controlling up to 8 stepper motors with the AccelStepper library, comes with the matching AccelStepperI2C library.

This documentation is probably only relevant for you if you want to change the firmware. Otherwise, the library documentation should suffice.

Author

Copyright (c) 2022 juh

License

This program 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, version 2.

Todo:

return messages (results) should ideally come with an id, too, so that master can be sure it's the correct result. Currently only CRC8, i.e. correct transmission is checked.

volatile variables / ATOMIC_BLOCK(ATOMIC_RESTORESTATE) {}

Module support (Servo, pin control, ...) needs to be outsourced and centralized. Currently there are a number of places that need to be adapted if a new module is added: Init section, startup message in setup(), processMessage().

make i2c address configurable with pins or via i2c/EEPROM

implement endstops/reference positions

Classes
struct	Endstop
struct	Stepper
	This struct comprises all stepper parameters needed for local slave management. More...

Macros
#define	SERVO_SUPPORT
#define	PINCONTROL_SUPPORT
#define	DEBUG
	Uncomment this to enable time keeping diagnostics. You probably should disable debugging, as Serial output will distort the measurements severely. Diagnostics take a little extra time and ressources, so you best disable it in production environments. More...
#define	log(...)   Serial.print(__VA_ARGS__)
#define	EEPROM_OFFSET_I2C_ADDRESS   0

Functions
uint8_t	retrieveI2C_address ()
	Read a stored I2C address from EEPROM. If there is none, use default. More...
void	storeI2C_address (uint8_t newAddress)
	Write I2C address to EEPROM. More...
void	resetFunc ()
void	setup ()
	Setup system. Retrieve I2C address from EEPROM or default and initialize I2C slave. More...
int8_t	addStepper (uint8_t interface=AccelStepper::FULL4WIRE, uint8_t pin1=2, uint8_t pin2=3, uint8_t pin3=4, uint8_t pin4=5, bool enable=true)
	Assign and initialize new stepper. Calls the AccelStepper's[1/2] constructor More...
uint8_t	pollEndstops (uint8_t s)
void	triggerInterrupt (uint8_t source, uint8_t reason)
void	clearInterrupt ()
void	loop ()
	Main loop, implements the state machine. Will check for each stepper's state and do the appropriate polling (run() etc.) as needed. Also checks for incoming commands and passes them on for processing. More...
void	receiveEvent (int howMany)
	Handle I2C receive event. Just read the message and inform main loop. More...
bool	validStepper (int8_t s)
bool	validServo (int8_t s)
void	processMessage (uint8_t len)
void	writeOutputBuffer ()
void	requestEvent ()
	Handle I2C request event. Will send results or information requested by the last command, as defined by the contents of the outputBuffer. More...

Variables
const uint8_t	slaveDefaultAddress = 0x08
const uint8_t	maxServos = 4
Servo	servos [maxServos]
uint8_t	numServos = 0
volatile uint8_t	writtenToBuffer = 0
volatile uint8_t	sentOnRequest = 0
uint32_t	now
uint32_t	then = millis()
bool	reportNow = true
uint32_t	lastCycles = 0
const uint32_t	reportPeriod = 2000
uint32_t	cycles = 0
const uint32_t	eepromI2CaddressMarker = 0x12C0ACCF
SimpleBuffer *	bufferIn
SimpleBuffer *	bufferOut
volatile uint8_t	newMessage = 0
int8_t	interruptPin = -1
bool	interruptActiveHigh = true
uint8_t	interruptSource = 0xF
uint8_t	interruptReason = interruptReason_none
const uint8_t	maxEndstops = 2
const uint32_t	endstopDebouncePeriod = 5
const uint8_t	maxSteppers = 8
uint8_t	numSteppers = 0
Stepper	steppers [maxSteppers]

Macro Definition Documentation

DEBUG

#define DEBUG

Uncomment this to enable time keeping diagnostics. You probably should disable debugging, as Serial output will distort the measurements severely. Diagnostics take a little extra time and ressources, so you best disable it in production environments.

Uncomment this to enable firmware debugging output on Serial.

EEPROM_OFFSET_I2C_ADDRESS

#define EEPROM_OFFSET_I2C_ADDRESS   0

log

#define log

(

...

)

Serial.print(__VA_ARGS__)

PINCONTROL_SUPPORT

#define PINCONTROL_SUPPORT

SERVO_SUPPORT

#define SERVO_SUPPORT

Function Documentation

addStepper()

int8_t addStepper	(	uint8_t	interface = AccelStepper::FULL4WIRE,
		uint8_t	pin1 = 2,
		uint8_t	pin2 = 3,
		uint8_t	pin3 = 4,
		uint8_t	pin4 = 5,
		bool	enable = true
	)

Assign and initialize new stepper. Calls the AccelStepper's[1/2] constructor

Returns

internal number (0-7) of stepper assigned to new stepper, -1 for error

clearInterrupt()

void clearInterrupt

(

)

loop()

void loop

(

)

Main loop, implements the state machine. Will check for each stepper's state and do the appropriate polling (run() etc.) as needed. Also checks for incoming commands and passes them on for processing.

Todo:

endstop polling: overhead to check if polling is needed (timeToCheckTheEndstops) might cost more than it saves, so maybe just check each cycle even if it might be much more often than needed.

pollEndstops()

uint8_t pollEndstops

(

uint8_t

s

)

processMessage()

void processMessage

(

uint8_t

len

)

@ brief Process the message stored in bufferIn with lenght len which was received via I2C. Messages consist of at least three bytes: [0] CRC8 checksum [1] Command. Most commands correspond to an AccelStepper or Servo function, some are new for I2C reasons. Unknown commands are ignored. [2] Number of the stepper or servo unit that is to receive the command. If no unit with this number exists, the message is ignored, except for general wrapper commands like resetCmd, which ignore this parameter. [3..maxBuffer] Optional parameter bytes. Each command that comes with too many or too few parameter bytes is ignored.

Note

Blocking functions runToPositionCmd() and runToNewPositionCmd() not implemented here. Blocking at the slave's side seems not too useful, as the master won't wait for us anyway,

Todo:

Implement blocking functions runToPositionCmd() and runToNewPositionCmd() on the master's side/in the library?

receiveEvent()

void receiveEvent

(

int

howMany

)

Handle I2C receive event. Just read the message and inform main loop.

Todo:

Just read the buffer here, move interpretation out of the interrupt.

requestEvent()

void requestEvent

(

)

Handle I2C request event. Will send results or information requested by the last command, as defined by the contents of the outputBuffer.

Todo:

<done>Find sth. meaningful to report from requestEvent() if no message is pending, e.g. current position etc.</done> not implemented, ESP32 can't do that (doh)

resetFunc()

void resetFunc

(

)

retrieveI2C_address()

uint8_t retrieveI2C_address

(

)

Read a stored I2C address from EEPROM. If there is none, use default.

setup()

void setup

(

)

Setup system. Retrieve I2C address from EEPROM or default and initialize I2C slave.

storeI2C_address()

void storeI2C_address

(

uint8_t

newAddress

)

Write I2C address to EEPROM.

Note

ESP eeprom.h works a bit different from AVRs: https://arduino-esp8266.readthedocs.io/en/3.0.2/libraries.html#eeprom

triggerInterrupt()

void triggerInterrupt	(	uint8_t	source,
		uint8_t	reason
	)

validServo()

bool validServo

(

int8_t

s

)

validStepper()

bool validStepper

(

int8_t

s

)

writeOutputBuffer()

void writeOutputBuffer

(

)

Variable Documentation

bufferIn

SimpleBuffer* bufferIn

bufferOut

SimpleBuffer* bufferOut

cycles

uint32_t cycles = 0

eepromI2CaddressMarker

const uint32_t eepromI2CaddressMarker = 0x12C0ACCF

endstopDebouncePeriod

const uint32_t endstopDebouncePeriod = 5

interruptActiveHigh

bool interruptActiveHigh = true

interruptPin

int8_t interruptPin = -1

interruptReason

uint8_t interruptReason = interruptReason_none

interruptSource

uint8_t interruptSource = 0xF

lastCycles

uint32_t lastCycles = 0

maxEndstops

const uint8_t maxEndstops = 2

maxServos

const uint8_t maxServos = 4

maxSteppers

const uint8_t maxSteppers = 8

newMessage

volatile uint8_t newMessage = 0

now

uint32_t now

numServos

uint8_t numServos = 0

numSteppers

uint8_t numSteppers = 0

reportNow

bool reportNow = true

reportPeriod

const uint32_t reportPeriod = 2000

sentOnRequest

volatile uint8_t sentOnRequest = 0

servos

Servo servos[maxServos]

slaveDefaultAddress

const uint8_t slaveDefaultAddress = 0x08

steppers

Stepper steppers[maxSteppers]

then

uint32_t then = millis()

writtenToBuffer

volatile uint8_t writtenToBuffer = 0