load_program.py

#!/usr/bin/env python3
"""
RISC-V program loader for Basys3
Sends a .hex file over UART to the uart_program_loader module.

Usage:
    python3 load_program.py program.hex
    python3 load_program.py program.hex --port /dev/ttyUSB1
    python3 load_program.py program.hex --port COM3 --baud 115200
"""

import serial
import time
import sys
import argparse

# -------------------------------------------------------
# Argument parsing
# -------------------------------------------------------
parser = argparse.ArgumentParser(description="Load a RISC-V hex program onto Basys3 over UART")
parser.add_argument("hex_file",              help="Path to the .hex program file")
parser.add_argument("--port",  default="/dev/ttyUSB1", help="Serial port (default: /dev/ttyUSB0)")
parser.add_argument("--baud",  default=115200, type=int, help="Baud rate (default: 115200)")
parser.add_argument("--delay", default=0.01,  type=float, help="Delay between words in seconds (default: 0.01)")
args = parser.parse_args()

# -------------------------------------------------------
# Read hex file
# -------------------------------------------------------
words = []
try:
    with open(args.hex_file, 'r') as f:
        for lineno, line in enumerate(f, 1):
            line = line.strip()
            if not line or line.startswith("//") or line.startswith("#"):
                continue
            try:
                word = int(line, 16)
                words.append(word)
            except ValueError:
                print(f"Warning: skipping invalid line {lineno}: '{line}'")
except FileNotFoundError:
    print(f"Error: file '{args.hex_file}' not found")
    sys.exit(1)

if not words:
    print("Error: no valid words found in hex file")
    sys.exit(1)

print(f"Loaded {len(words)} words ({len(words) * 4} bytes) from '{args.hex_file}'")

# -------------------------------------------------------
# Send over UART
# -------------------------------------------------------
try:
    with serial.Serial(args.port, args.baud, timeout=2) as ser:
        print(f"Opened {args.port} at {args.baud} baud")
        print("Sending program...")

        for i, word in enumerate(words):
            # Little-endian: LSB first
            data = word.to_bytes(4, byteorder='little')
            ser.write(data)
            time.sleep(args.delay)

            # Progress bar
            pct = (i + 1) / len(words) * 100
            bar = '█' * int(pct / 2) + '░' * (50 - int(pct / 2))
            print(f"\r[{bar}] {pct:.1f}% ({i+1}/{len(words)} words)", end='', flush=True)

        print()  # newline after progress bar

        # Send end sequence: 4x 0xFF
        print("Sending end sequence (0xFF 0xFF 0xFF 0xFF)...")
        ser.write(bytes([0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF]))
        time.sleep(0.1)

        print("Done! CPU should now be running your program.")

except serial.SerialException as e:
    print(f"Serial error: {e}")
    print(f"Make sure the board is connected and '{args.port}' is correct")
    sys.exit(1)