Library for TMC2209 driver - AVR

This library is used to control one or more TMC2209 modules via UART using an AVR microcontroller. Apart from reading and writing the TMC2209 registers, this library can also be used to drive a stepper motor by using the stepperCon library in the background. The stepperCon library provides non blocking functions by using an interrupt, to drive multiple stepper motors with custom acceleration and speed, to keep track of motor positions, 3-axis motor coordination, as well as other useful functions. UART library is also provided that can use up to 2 USART peripherals at the same time: one for interfacing with the driver IC and one for debugging (assuming the microcontroller has two USART peripherals). 

The serial communication has some extra features for checkup such as:

• reads the interface transmission counter (IFCNT) register after every write to ensure the IC received the correct data.
• compares CRCs.
• checks if correct number of bytes has been received.
• if an error occurs it retries 2 times then sets a communication error flag that the user can check after each function is executed and take the appropriate action if an error occurs. 

The principle of operation is read-modify-write so there is no need to keep all driver IC registers in memory. The library only uses an 8 bytes union structure called replyDatagram where received and data to send is stored temporary.

If you wish to learn on how to wire the TMC2209 driver, you can find a tutorial here.

Contents

• Library Structure
• Default Settings
• Usage
• Documentation
• Create a structure object for each driver
• Initialization
• Read IC version
• Read Global Status Flags (GSTAT)
• GSTAT check if module was Reset
• GSTAT check if Driver Error
• GSTAT check if Charge Pump is Under Voltage
• Status check for UART error
• Read register PWM_SCALE_SUM
• Read register PWM_SCALE_AUTO
• Read register PWM_OFS_AUTO
• Read register PWM_GRAD_AUTO
• Read register SG_RESULT (StallGuard)
• Read register TSTEP
• Read register DRV_STATUS (Driver Status Flags)
• DRV_STATUS check Standstill
• DRV_STATUS check Chopper type
• DRV_STATUS check CS_ACTUAL
• DRV_STATUS check Temperature flags
• DRV_STATUS check Open Load flags
• DRV_STATUS check Low Side Short flags
• DRV_STATUS check Short to Ground flags
• DRV_STATUS check Over-temperature flag
• DRV_STATUS check Over-temperature Pre-warning flag
• Set micro-step resolution
• Set speed
• Set acceleration and deceleration
• Set direction
• Set chopper
• Set SpreadCycle threshold
• Set register IHOLD_IRUN
• Set register TPOWERDOWN
• Set register SGTHRS (StallGuard)
• Set register TCOOLTHRS (CoolStep threshold)
• Set register COOLCONF (CoolStep)
• Set Standstill mode
• Enable/disable driver by software
• Move to absolute position
• Move to relative position
• Start TMC2209 internal step generator
• Stop TMC2209 internal step generator
• StealthChop Automatic Tuning (AT)
• Download

TMC2209 stepper driver module tutorial

My first stepper driver module was A4988 and recently I have decided to give TMC2209 a try hearing how silent and energy efficient it is. Driving the A4988 is simple - just set direction, pulse the step pin and the motor moves. You can do the same thing with TMC2209 but this thing can do much more. It has UART interface, registers, algorithms and an 83 pages datasheet. I might be slow but I had to read the datasheet 3 times to wrap my head around on what things can this thing do. In my opinion it is a very good stepper driver so I made a library for it and also this tutorial to better help in using the library. Although the IC presented in this tutorial is TMC2209, most information can still be applied to other TMC ICs.

Contents

• TMC2209 description
• Modes of operation
• TMC2209 module pinout
• Attaching the TMC2209 to a microcontroller UART
• Setting the analog motor current
• Setting the digital motor current
• Automatic Standstill Power Down
• StealthChop2 and SpreadCycle Driver
• StealthChop
• StealthChop Automatic Tuning
• Freewheeling and Passive Braking
• SpreadCycle
• Combine StealthChop and SpreadCycle
• StallGuard4 Load Measurement
• StallGuard4 vs. StallGuard2
• Tuning StallGuard4
• StallGuard4 Update Rate
• Detecting a Motor Stall
• Limits of StallGuard4 Operation
• CoolStep Operation
• Setting up CoolStep
• Tuning CoolStep
• Response Time
• Driver Diagnostic Flags
• Temperature Measurement
• Short Protection
• Open Load Diagnostics
• Diagnostic Output
• Internal Step Pulse Generator
• External Reset
• Links

 

TMC2209 description

The TMC2209 is an ultra-silent motor driver IC for two phase stepper motors, developed by trinamic. TMC2209 pinning is compatible to other drivers as well as to the TMC2208. 

Multiple versions of modules can be found that are using this IC, however the stand-alone chip can be used for a DIY module that could provide some cost savings.

Features:

• 2-phase stepper motors up to 2.8A coil current (peak), 2A RMS
• STEP/DIR Interface with 8, 16, 32 or 64 microstep pin setting
• Smooth Running 256 microsteps by MicroPlyer™ interpolation
• StealthChop2™ silent motor operation
• SpreadCycle™ highly dynamic motor control chopper
• StallGuard4™ load and stall detection for StealthChop
• CoolStep™ current control for energy savings up to 75%
• Low RDSon, Low Heat-Up LS 170mΩ & HS 170mΩ (typ. at 25°C)
• Voltage Range 4.75… 29V DC
• Internal Sense Resistor option (no sense resistors required)
• Passive Braking, Freewheeling, and automatic power down
• Single Wire UART & OTP for advanced configuration options
• Integrated Pulse Generator for standalone motion

 

Pin interrupt library for AVR microcontrollers

This library can help to easily configure a pin interrupt on AVR microcontrollers without the need to check the datasheet every time. At the moment only PCINT pins are supported.

In this blog post, I will explain how to use interrupts on AVR microcontrollers. Interrupts are a powerful feature that allow the microcontroller to respond to external or internal events without constantly polling for them. Interrupts can improve the performance and efficiency of your code, as well as enable new functionalities.

What are interrupts?

An interrupt is a signal that causes the microcontroller to temporarily stop its current execution and jump to a special function called an interrupt service routine (ISR). The ISR performs the necessary actions to handle the interrupt, and then returns to the original program flow. The ISR can be triggered by various sources, such as:

• External pins (EXTINT)
• Pin changes (PCINT)
• Timers/Counters (TIMER)
• Serial communication (USART, SPI, TWI)
• Analog-to-digital conversion (ADC)
• Analog comparator (AC)
• Watchdog timer (WDT)
• EEPROM ready (EE READY)
• Store program memory ready (SPM READY)

stepperCon library for controlling stepper motor drivers using timer interrupt on AVR devices

The stepperCon library allows you to control multiple stepper motors at the same time. It can interface with any stepper motor driver that can take inputs such as step and direction. The library also has some extra useful functionalities such as motor coordination using Bresenham line algorithm - useful for controlling 3 axis motors for example, free spin - where the motor keeps spinning, and positioning the motor at a certain degree from 1 to 360 by finding the shortest path.

The maximum speed (step rate) on a 16MHz microcontroller is 25kHz, however the maximum practical speed is 6.25kHz or 8.33kHz depending on the motor, load, supply voltage and micro-step resolution. A higher voltage can yield higher RPM and with 1/32 micro-step resolution the step rate can be 25kHz as oppose to 6.25kHz when using 1/8 micro-step resolution.

Even with multiple motors running at the same time, the speed can be maintained and that is because the speed profile is segmented and calculated while the interrupt routine (ISR) is not executing steps. So the time spent inside the ISR is low since the calculations for acceleration and deceleration are not done there. Only the stepping is done inside the ISR. Having an interrupt to generate the steps is preferred over a function in the main loop where other code could delay the stepping function thus causing motor stuttering.

The stepper library includes the micros library that is used to trigger a timer interrupt every 40us and as a perk you also have a way to keep track of time in your project with a 40us time resolution.

 

stepperCon library characteristics

• interface with multiple stepper motor drivers
• up to 3 coordinated motors for X, Y and Z (can be extended for more)
• maximum stepping rate speed of 6.25kHz (or 8.33kHz if the motor can have high acceleration). Speeds are given for a 16MHz CPU. With higher CPU clock the stepping rate will also be higher.
• angular positioning function that finds the shortest path from current angle to target angle
• perpetual motion
• timer interrupt driven
• individual settings for acceleration and deceleration

Plotting data from a logic analyzer - CSV and LibreOffice Calc

Sometimes it is useful to visualize data from a logic analyzer in a graphical way but unfortunately not many applications can do that so I came up with a solution involving CSV data and LibreOffice Calc. Here I am using Logic from Saleae but any software that can export the data to a CSV file can work.

Usage

First thing to do is to export the data from the logic analyzer software to a CSV file format. In Logic 2 this can be easily achieved by going to File -> Export Data or by pressing CTRL + SHIFT + S.

Breadboard Development Board for AVR microcontrollers | Breaduino

A development board is an essential tool when working with projects that involve a microcontroller and most of the time you will also need a breadboard and a power supply. So why not combining all these in a single product?

Meet Breaduino - a custom development board build around ATmega328PB microcontroller. If you are a beginner in electronics or microcontrollers, building a development board is not only rewarding but also educational.

The Breaduino dev board is designed to be used with two breadboards where it outputs three voltages: 12V, 5V and 3.3V. It includes a TFT display, micro SD card socket, input current measurement and a rotary encoder for user interaction. On the right side of the case is space for a small logic analyzer and/or a 9V battery. All these are optional modules. Even the breadboard is optional so the board can be used standalone. Since this is a customizable board it can be modified to fit your needs.