Management of two stepper motors

Based on STM32F030F4P6

Pinout

Pin	Type	Role
PA0	AIN	Steppers current
PA1	AIN	Input voltage 12V
PA2	AIN	EndSwitch1 of motor0
PA3	AIN	EndSwitch0 of motor0
PA4	PUPD	Tim14Ch1 - motor0 steps
PA5	PUPD	Motor1 enable
PA6	PUPD	Tim3Ch1 - motor1 steps
PA7	PUPD	Motor1 direction
PA9	OD	USART1 Tx
PA10	FIN	USART1 Rx
PA13	FINPU	EndSwitch0 of motor1
PA14	FINPU	EndSwitch1 of motor1
PB1	PUPD	Turn off current sensor
PF0	PUPD	Motor0 enable
PF1	PUPD	Motor0 direction

Protocol

Any command have format “# CMD”, where # is device ID (the_conf.devID) or “-1” if there’s only one device at the bus. After it can be any number of spaces and command symbols. If the command recognized and it’s right, ALL OK would be returnded. If the command is bad, answer BADCMD. Error in command sintax: ERR. If the answer would take more than one line it would be ends by DATAEND.

First symbol of commands

(nothing except spaces) - ping command, device with given ID answers: ALIVE
G - one of the Getters (depending on next text)
M - motors' manipulation
R - make MCU software reboot (next status getter will return SOFTRESET=1)
S - one of the Setters
W - write flash command, use it to save new configuration data

All wrong commands will return BADCMD, commands with bad format or wrong number return ERR. Commands with lot of output ends with DATAEND. Some commands (like flash write) will return just ALL OK if succeed.

Getters

Getters returning more than one field ends with DATAEND meaning that’s all data.

A - get ADC value
- D - Vdd value (*100 Volts), e.g. VDD=330
- I - total motors' current (*100 Amperes), e.g. IMOT=123
- M - motor’s voltage (*100 Volts), e.g. VMOT=1193
C - get current configuration, e.g.

CONFSZ=36 DEVID=0 V12NUM=1 V12DEN=10 I12NUM=1 I12DEN=1 V33NUM=1 V33DEN=1 ESWTHR=150 MOT0SPD=60 MOT1SPD=60 USARTSPD=115200 REVERSE0=0 REVERSE1=0 MAXSTEPS0=0 MAXSTEPS1=0 DATAEND

All variables here are fields of user_conf struct.
R - get raw ADC values:
- 0 - Steppers current
- 1 - Input voltage 12V
- 2 - EndSwitch2 of motor1
- 3 - EndSwitch1 of motor1
- 4 - inner temperature
- 5 - vref
E.g.:

ADC[0]=4095 ADC[1]=2340 ADC[2]=4095 ADC[3]=4087 ADC[4]=1665 ADC[5]=1532 DATAEND
S - get motors' status.

Values of MOTORx (state of given motor) can be one of following:
- ACCEL - start moving with acceleration
- DECEL - moving with deceleration
- MOVE - moving with constant speed
- MOVETO0 - move towards 0 endswitch (negative direction)
- MOVETO1 - move towards 1 endswitch (positive direction)
- MVSLOW - moving with slowest constant speed
- SLEEP - don’t moving (normal state)
- STOP - stop motor right now (by demand)
- STOPZERO - stop motor and zero its position (on end-switch)
- UNKNOWN - something wrong
Values of ESWxy (state of end-switch y of motor x) can be:
- BTN - user button pressed
- ERR - wrong ADC value
- HALL - hall switch activated
- RLSD - no actions
If reset occurs there’s two additional fields on first request after reset:
- WDGRESET=1 - watchdog’s reset occured
- SOFTRESET=1 - software (by user’s demand) reset occured
There also two fields:
- POSx - position of given motor (negative values means that initialisation need)
- STEPSLEFTx - (only when moving) amount of steps left
E.g.: SOFTRESET=1 MOTOR0=SLEEP POS0=-1 ESW00=ERR ESW01=BTN MOTOR1=SLEEP POS1=-1 ESW10=HALL ESW11=HALL
T - get MCU temperature, e.g. TEMP=365

Motors' manipulation

Next char should be ‘0’ or ‘1’ — motor’s number. If wrong, BADCMD answer would be returned. There’s only two commands in this section:

Mnum - move motor to num steps. Errors:
- BadSteps - num isn’t a number
- IsMoving - motor is still moving, stop it before
- OnEndSwitch - the motor is on end-switch limiting moving in given direction
- ZeroMove - user wants to move for 0 steps
- TooBigNumber - amount of steps is greater than MAXSTEPSx
S - stop motor

Setters

Change of any setter takes place in MCU RAM immediately. To store them permanently run write flash command.

A num - set value of ACCDECSTEPS (approximate amount of steps to do acceleration/deceleration) to num
C#num - set current speed to num for motor #
D$num - set denominator $ (D - Vdd, I - current, M - 12V) to number num
E$num - set numerator $
I num - set device ID
M#num - set maxsteps (num is 1..65535) for motor #
P num - properties of internal pullup (0 - disabled, other or without num - enabled)
R#num - set reverse for motor # (num == 0 turns reverse off, num == 1 turns it on)
S#num - set speed (motspd) to num for motor #
T num - set end-switches threshold (in ADU, near 0 for Hall switch, 2048 for user button and 4096 for released state)
U num - set USART speed to num bits per second
u num - set value of USTEPS (amount of microsteps per one step)

Motor speed setters

To set motor speed to N steps per second, give command C or S with argument equal to 3000/N. E.g. to set current speed for DevID=0, motor0 to 50 steps per second give command 0SC060.

Denominator and numerator setters

Have naxt letter similar to ADC getter (D - Vdd, I - motors' I, or M - motors' U). The value of numerator shouldn’t be very large as uint32_t used in multiplications.

Device ID setter

After this command device will immediately change it’s ID, if you “lost” device after this procedure you should reboot it or (if there’s only one device on the bus) call it by “universal ID” (-1).

USART speed setter

The USART speed will be changed after next reset (e.g. by MCU software reboot command), so it don’t work without storing in the flash. Check it twice before writing as wrong numbers can make device lost until next re-flashing.