Lab 1 - LED Blinking Demo on DT1260 with Sci-Compiler

This project demonstrates two different ways to blink an LED using the DT1260 development kit and Sci-Compiler blocks. Both examples produce the same effect—an LED blinking at a set frequency—but use two distinct implementation approaches:

1. A low-level counter approach
2. An integrated Pulse Generator (PWM) block

Below you can see schematic captures for each design (the images in this repository).

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1. Low-Level Counter Approach

In this implementation, we manually create the blinking behavior by:

1. Counting Clock Cycles

   • We use the Chrono (Enable) block to count clock pulses (at 65 MHz) whenever the ENABLE input is high.
   • The current count is output on the TIME pin of the Chrono block.

2. Comparing to Thresholds

   • Two Comparator (GREATER) blocks check if the TIME count exceeds two different thresholds:
     • For example:
       • Threshold 1 = 10,000,000
       • Threshold 2 = 15,000,000
   • Both thresholds are fed from Const Bit-Vector blocks of size 32 bits.

3. Set/Reset Flip-Flop

   • The outputs from the two comparators drive a FF SET-RESET block.
   • When the count passes the first threshold, the flip-flop is set.
   • When the count passes the second threshold, the flip-flop is reset and (if configured) the Chrono can be reset or continue counting based on the logic we design.

4. LED Outputs

   • The flip-flop’s output is sent to LED_0.
   • An inverter (Logic Not) drives LED_1 from the same flip-flop signal, so you can see two complementary blinking signals if desired.

This design conceptually works like this:

• The Chrono block counts rising edges of the 65 MHz clock.
• After a certain count (e.g., 10,000,000 cycles), we set the flip-flop.
• After a higher count (e.g., 15,000,000 cycles), we reset the flip-flop.
• The block can then reset or continue (depending on how we wire it), so that the cycle repeats.

Result: The flip-flop output toggles in a timed manner, blinking the LED at a predictable rate based on the clock frequency and the comparison thresholds.

Chrono (Enable) Block Basics

• Enable: When high, it starts counting.
• Time (32 bits): Outputs the current count.
• Overflow: Goes high if the count exceeds the maximum 32-bit range.
• Auto Reset: Automatically resets the counter on overflow when high.
• Reset: When high, it zeroes the counter and restarts the count.

(See the included documentation excerpt for a full explanation.)

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2. Integrated Pulse Generator (PWM) Approach

For a simpler design, we can generate the blinking (or a PWM-like signal) directly using the Pulse Generator (PWM) block:

1. PULSE_PERIOD & PULSE_WIDTH

   • Two Const Bit-Vector inputs define the period and width in clock cycles.
   • For example:
     • Period = 15,000,000 clock cycles
     • Width = 5,000,000 clock cycles
   • At 65 MHz, 15,000,000 cycles corresponds roughly to a 0.23 second period.

2. CLK & RESET

   • The PWM block’s CLK runs at 65 MHz (like the DT1260 default).
   • The RESET can be driven by a global reset or other logic.

3. Output

   • The PWM output pin (PULSE) drives the LED_1.
   • Whenever PULSE_WIDTH has elapsed, the signal transitions from high to low (or vice versa), creating a blinking effect.

Result: A blinking signal is generated directly without needing explicit counters or comparators. By changing the PULSE_PERIOD and PULSE_WIDTH, you can easily adjust blink frequency and duty cycle.

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Notes on Clock Settings

• Both designs rely on the 65 MHz clock on the DT1260.
• For each approach, the LED blink rate is directly tied to the chosen clock cycle thresholds.

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How to Use This Project

1. Open the Sci-Compiler project files in your workspace.
2. Build (synthesize) the design for the DT1260 development kit.
3. Load the bitstream onto the board.
4. Observe that:
   • In the counter-based design, LED_0 and LED_1 toggle at the configured thresholds.
   • In the PWM-based design, the output LED_1 is driven by the Pulse Generator block’s duty cycle.

You can modify the constants (10,000,000, 15,000,000, or 5,000,000 in the examples) to change how fast the LED toggles.

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Further Reading

• Chrono (Enable) Documentation: Explains count, overflow, and reset functionality.
• Comparator (GREATER) Documentation: Details how numeric comparisons are performed.
• Pulse Generator (PWM) Documentation: Shows how to generate periodic or PWM-like signals.

These blocks are part of the Sci-Compiler library from Nuclear Instruments SRL.

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Enjoy experimenting! If you have questions, refer to the component guides or your local lab instructions.