Stepper Interval Timer

NetBurner SAME70 Stepper Motor Interval Timer Example

Overview

This example demonstrates how to use the NetBurner SAME70 platform's interval timer functionality to generate precise timing signals for stepper motor control. The application configures a hardware timer to produce step and direction signals that can drive stepper motor controllers.

Supported Platforms

• MODM7AE70
• SBE70LC

Features

• Hardware-based interval timer configuration
• Variable step frequency control (steps per second)
• Bidirectional control (up/down counting)
• Real-time command interface via serial console
• Timer channel configuration for stepper motor applications

Hardware Configuration

Pin Assignments

MODM7AE70:**

• P2.25: TIOB11 (Timer channel B output)

• P2.28: TIOA11 (Timer channel A output - step signal)

  SBE70LC:**

• J1.4: TIOA11 (Timer channel A output - step signal)

Timer Configuration

The application uses Timer Channel 11 (STEPPER_TIMER) configured in stepper mode with the following features:

• Configurable frequency from 0 to several thousand steps per second
• Direction control via up/down counting
• Hardware-generated step pulses
• Interrupt-free operation for precise timing

Application Flow

System Initialization
         |
         v
Pin Function Setup
         |
         v
Timer Allocation
         |
         v
User Command Loop
         |
         v
  +-------------+
  | User Input  |
  | <steps><dir>|
  +-------------+
         |
         v
    Process Command
         |
    +----+----+
    |         |
    v         v
Update      Stop
Timer      Timer

User Interface

The application provides a simple command-line interface for controlling the stepper motor timing:

Command Format

<steps per second><U/D>

Where:

• Steps per second: Integer value (0 to stop)
• Direction: 'U' or 'u' for up, 'D' or 'd' for down

Usage Examples

> 300D
    300 steps per second, counting Down
 
> 2000U  
    2000 steps per second, counting Up
 
> 0U
    Stop, 0 steps per second

Key Functions

Timer Management

• InitStepperTimer(int pps, bool dirUp) - Initialize timer with frequency and direction
• UpdateStepperTimer(int pps, bool dirUp) - Update running timer parameters
• StopStepperTimer() - Stop timer operation

Hardware Configuration

• Pin function assignment for timer outputs
• Timer channel configuration in stepper mode
• Interrupt disable for hardware-only operation

Important Notes

• On MODM7AE70 MOD-DEV-70, P2.28 is connected to SPI DOUT, so the flash card socket must be empty when using this example
• Timer interrupts are disabled to allow pure hardware generation of step signals
• The timer operates independently once configured, providing precise timing without CPU intervention
• Direction changes and frequency updates can be made in real-time

Application Notes

This example is particularly useful for:

• Stepper motor control applications
• Precision timing signal generation
• Learning SAME70 timer capabilities
• Hardware-based pulse generation without software overhead

The hardware timer approach ensures consistent timing regardless of CPU load or interrupt activity, making it ideal for applications requiring precise motor control timing.