ShrikeFlash

Arduino library for flashing FPGA bitstreams over SPI on RP2040 microcontrollers.

Features

• Flash FPGA bit-streams from LittleFS filesystem
• Configurable SPI settings and pin mapping
• Transfer timing statistics and performance monitoring
• File management utilities (list, check, delete files)
• Easy-to-use API with detailed serial output

Hardware Requirements

• Shrike Dev Board

Default Pin Configuration

Function	RP2040 Pin	Description
EN	GPIO 13	FPGA Enable
PWR	GPIO 12	FPGA Power
SS	GPIO 1	SPI Chip Select
SCK	GPIO 2	SPI Clock
MOSI	GPIO 3	SPI Data Out
MISO	GPIO 0	SPI Data In

Installation

Via Arduino Library Manager (Once Published)

1. Open Arduino IDE
2. Go to Sketch → Include Library → Manage Libraries
3. Search for "ShrikeFlash"
4. Click Install

Manual Installation

1. Download the latest release from GitHub
2. Extract the ZIP file
3. Move the ShrikeFlash folder to your Arduino libraries directory:
   • Windows: Documents\Arduino\libraries\
   • Mac: ~/Documents/Arduino/libraries/
   • Linux: ~/Arduino/libraries/
4. Restart Arduino IDE

Usage

Basic Example

#include <Shrike.h>

ShrikeFlash fpga;

void setup() {
  Serial.begin(115200);
  while (!Serial && millis() < 3000);
  
  // Initialize the library
  if (!fpga.begin()) {
    Serial.println("Initialization failed!");
    while(1);
  }
  
  // Flash the FPGA
  fpga.flash("/bitstream.bin");
}

void loop() {
  // Your code here
}

Upload Bitstream Files

1. Create a data folder in your sketch directory
2. Place your .bin bitstream files in the data folder
3. Use Tools → Pico LittleFS Data Upload to upload files to the RP2040
4. Upload your sketch

Custom Pin Configuration

// ShrikeFlash(EN, PWR, SS, SCK, MOSI, MISO)
ShrikeFlash fpga(13, 12, 1, 2, 3, 0);

void setup() {
  fpga.begin();
  fpga.flash("/custom_bitstream.bin");
}

API Reference

Initialization

begin(spi_speed)

Initialize the library with optional SPI speed.

• Parameters: spi_speed (default: 1600000 Hz)
• Returns: bool - true if successful

fpga.begin();              // Default 1.6 MHz
fpga.begin(2000000);       // Custom 2 MHz

Flashing

flash(filename, word_size)

Flash FPGA with bitstream file.

• Parameters:
  • filename - Path to bitstream file (e.g., "/bitstream.bin")
  • word_size - Transfer chunk size (default: 46408 bytes)
• Returns: bool - true if successful

fpga.flash("/led_blink.bin");
fpga.flash("/custom.bin", 8192);  // Custom chunk size

reset()

Reset the FPGA (power cycle).

fpga.reset();

Timing & Statistics

getLastFlashTime()

Get the time taken for last flash operation.

• Returns: unsigned long - Time in milliseconds

unsigned long time = fpga.getLastFlashTime();
Serial.print("Flash took: ");
Serial.print(time);
Serial.println(" ms");

getTransferRate()

Get the transfer rate of last flash operation.

• Returns: float - Transfer rate in KB/s

float rate = fpga.getTransferRate();
Serial.print("Transfer rate: ");
Serial.print(rate);
Serial.println(" KB/s");

printStats()

Print detailed statistics of last flash operation.

fpga.printStats();
// Output:
// === Flash Statistics ===
// Time taken: 2345 ms
// Transfer rate: 85.32 KB/s
// ===========================

File Management

fileExists(filename)

Check if a file exists in LittleFS.

• Returns: bool

if (fpga.fileExists("/bitstream.bin")) {
  Serial.println("File found!");
}

getFileSize(filename)

Get file size in bytes.

• Returns: size_t - File size in bytes (0 if not found)

size_t size = fpga.getFileSize("/bitstream.bin");
Serial.print("File size: ");
Serial.print(size);
Serial.println(" bytes");

listFiles()

List all files in LittleFS filesystem.

fpga.listFiles();
// Output:
// === Files in LittleFS ===
//   /bitstream.bin - 135040 bytes
//   /led_blink.bin - 92416 bytes
// ===========================

deleteFile(filename)

Delete a file from LittleFS.

• Returns: bool - true if successful

if (fpga.deleteFile("/old_file.bin")) {
  Serial.println("File deleted successfully");
}

printFSInfo()

Print filesystem information (total, used, free space).

fpga.printFSInfo();
// Output:
// === Filesystem Info ===
// Total space: 2048 KB
// Used space: 256 KB
// Free space: 1792 KB
// ===========================

Complete Example

#include <Shrike.h>

ShrikeFlash fpga;

void setup() {
  Serial.begin(115200);
  while (!Serial && millis() < 3000);
  
  Serial.println("ShrikeFlash Example");
  
  // Initialize
  if (!fpga.begin()) {
    Serial.println("Failed to initialize!");
    while(1);
  }
  
  // Show filesystem info
  fpga.printFSInfo();
  
  // List available files
  fpga.listFiles();
  
  // Check if file exists
  if (!fpga.fileExists("/led_blink.bin")) {
    Serial.println("Bitstream file not found!");
    Serial.println("Please upload files using LittleFS Data Upload tool");
    while(1);
  }
  
  // Flash the FPGA
  Serial.println("Starting flash...");
  if (fpga.flash("/led_blink.bin")) {
    Serial.println("Flash successful!");
    
    // Print statistics
    fpga.printStats();
    
    Serial.print("Time: ");
    Serial.print(fpga.getLastFlashTime());
    Serial.println(" ms");
    
    Serial.print("Rate: ");
    Serial.print(fpga.getTransferRate(), 2);
    Serial.println(" KB/s");
  } else {
    Serial.println("Flash failed!");
  }
}

void loop() {
  // Empty
}

Troubleshooting

LittleFS Mount Failed

• Make sure you've selected a board configuration with LittleFS support
• Go to Tools → Flash Size and select an option with FS (e.g., "2MB Sketch + 2MB FS")
• Upload your files using Tools → Pico LittleFS Data Upload

File Not Found

• Ensure files are in the data folder of your sketch
• Use Tools → Pico LittleFS Data Upload before uploading sketch
• Check filenames match exactly (case-sensitive)

FPGA Not Programming

• Verify wiring connections
• Check power supply to FPGA
• Try reducing SPI speed: fpga.begin(800000);
• Verify bitstream file is valid

Board Support

This library requires the Arduino-Pico or Arduino Mbed OS RP2040 board package.

Install from Board Manager:

• Arduino-Pico: https://github.com/earlephilhower/arduino-pico
• Add to Board Manager URLs: https://github.com/earlephilhower/arduino-pico/releases/download/global/package_rp2040_index.json

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

License

MIT License - see LICENSE file for details