vguz_v2/SESSION_SUMMARY.md

Session Summary - 2025-11-23

Project: vguz_v2 - vzug-e-hinge Test & Control System

Session Overview

Implemented complete session lifecycle management with port conflict prevention and fixed critical UART parity bug.

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Work Completed This Session

1. Session Lifecycle Management with Port Conflict Prevention

Problem: When a session was loaded, UART and I2C tabs could still be accessed, potentially causing port conflicts. After session ended, there was no way to unload without starting the session.

Solution Implemented:

A. Session Widget (session_widget.py) - Lines modified:

• Line 101: Added self.main_window = None to store reference to main window
• Line 350: Added set_main_window() method to receive main window reference
• Lines 182-185: Added "Unload Session" button next to "Load Session"
• Lines 436, 500-504: Enable/disable Unload button appropriately
• Lines 422, 440: Call _disable_port_tabs() after successful load
• Lines 591, 605: Call _cleanup_session() in session finished and error handlers
• Lines 727-757: Added three new methods:
  • _disable_port_tabs() - Disables UART (tab 3) and I2C (tab 4) tabs
  • _enable_port_tabs() - Re-enables UART and I2C tabs
  • _cleanup_session() - Complete cleanup: unload session, close ports, re-enable tabs, disable buttons
• Lines 678-700: Modified _reset_controls() and _on_worker_finished() to NOT re-enable Start button (must Load again)

B. Session Module (session.py) - Lines 335-377:

• Added unload_session() method:
  • Closes all hardware ports (UART command, UART logger, I2C)
  • Clears session state variables
  • Resets execution flags
  • Preserves session_name for display
  • Does NOT clear UI selections (for easy re-run)

C. Enhanced Port Closing (session.py) - Lines 672-720:

• Improved _close_ports() with:
  • Individual try/catch for each port
  • 0.1s delays after stopping reader threads
  • 0.2s final delay for OS to release ports
  • Better error logging (warnings instead of errors)

D. Main Window (main.py) - Line 189:

• Added self.session_widget.set_main_window(self) to pass reference

Behavior Flow:

1. Initial State: All buttons disabled except Load
2. After Load: Start + Unload enabled, UART/I2C tabs DISABLED (grayed out)
3. After Start: Pause/Stop enabled, Unload disabled
4. After Session Ends: All buttons disabled, UART/I2C tabs RE-ENABLED, must Load again
5. Manual Unload: Click Unload button anytime before Start to regain tab access

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2. Duplicate Session Name Handling

Problem: Loading a session with a name that already exists in the database would cause conflicts or duplicate data.

Solution Implemented (session_widget.py - Lines 368-405):

• Check database for existing session name on Load
• Show QMessageBox dialog: "Session name '[name]' already exists. Override will delete existing session and telemetry data. Cancel or Override?"
• Cancel: Abort load, log info message
• Override: Delete all records with matching session_name from:
  • sessions table
  • telemetry_raw table
  • telemetry_decoded table
• Proceed with load after cleanup

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3. Critical Bug Fix: UART Parity Default

Problem: UART tab was throwing IO_ERROR on all ports immediately after program start, even though permissions were correct and it worked in old versions.

Root Cause: Recent commit 70eb585 changed UART defaults in uart_core.py:

# BROKEN (commit 70eb585):
parity: str = 'E'  # Even parity - devices expect None!
buffer_size: int = 0.256 * 1024 * 1024  # Float expression, wrong!

# FIXED:
parity: str = 'N'  # No parity
buffer_size: int = 256 * 1024  # 256KB, proper integer

Fix Applied (uart/uart_kit/uart_core.py - Lines 140-141):

• Reverted parity default from 'E' to 'N'
• Fixed buffer_size to proper integer calculation
• Corrected comment (was "4MB", actually 256KB)

Why Session Worked But UART Tab Didn't:

• Session explicitly sets parity from database interface profile
• UART tab widget also sets parity from UI
• But something in the initialization was using the default 'E' parity before the UI values were applied
• Changing default back to 'N' fixed it

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Current System State

Database Schema (Relevant Tables)

-- Session execution records
sessions (session_id PK, session_name, interface_profile_id, total_runs, status, notes, created_at)

-- Telemetry data (linked by session_name!)
telemetry_raw (session_id, session_name, t_ns, packet_no, raw_data)
telemetry_decoded (session_id, session_name, t_ns, run_no, motor_current, encoder_a, encoder_b, angle, ...)

Key Architectural Points

Tab Indices (main.py):

• Tab 0: Session
• Tab 1: Configure Session
• Tab 2: Configure Interface
• Tab 3: UART (disabled during session)
• Tab 4: I2C (disabled during session)
• Tab 5: Graph
• Tab 6: Database Manager

Session Execution Flow:

1. Load Session: Reads profiles from DB, does NOT open ports yet
2. Start Session: Opens ports via _open_ports(), starts execution
3. Session Runs: Commands executed via run.py
4. Session Ends: Signals emitted, _cleanup_session() called automatically
5. Cleanup: Ports closed, tabs re-enabled, buttons disabled

Port Management:

• UART Command Port: TX/RX for commands
• UART Logger Port: RX only for telemetry (optional)
• I2C: Angle sensor reads correlated to UART timestamps
• All ports opened on Start, closed on session end/unload

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Known Issues & Notes

Working Correctly:

✅ Session lifecycle (Load → Start → End → Cleanup) ✅ Port conflict prevention (tabs disabled during session) ✅ Manual unload (Unload button) ✅ Duplicate session name override ✅ UART tab port opening ✅ Multi-phase sessions (Init/Execute/De-init)

Code Quality Notes:

• Todo list system used to track progress (all tasks completed)
• Added sleep delays in port cleanup for proper OS release
• Individual error handling per port prevents cascading failures
• UI selections preserved after cleanup for easy re-run

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Files Modified This Session

Core Changes:

1. session_widget.py (main changes)

   • Added Unload button
   • Added tab enable/disable methods
   • Added cleanup_session() method
   • Modified button enable logic

2. session.py

   • Added unload_session() method
   • Enhanced _close_ports() with delays and error handling

3. main.py

   • Added set_main_window() call

4. uart/uart_kit/uart_core.py (CRITICAL BUG FIX)

   • Fixed parity default: 'E' → 'N'
   • Fixed buffer_size: float → int

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Quick Reference Commands

Run Application:

cd /home/key/git/vguz_v2
python main.py

Database Management:

# Initialize/recreate database
python database/init_database.py

# Recreate database (overwrite)
python database/init_database.py --overwrite

# Check database health
python database/init_database.py --check

Git Status:

# Check current changes
git status

# See what we modified
git diff

# Commit changes (when ready)
git add -A
git commit -m "Session lifecycle management + UART parity fix"

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Testing Checklist

Before next session, verify:

• UART tab opens ports correctly (all devices)
• Load Session → Unload Session → UART tab accessible
• Load Session → Start → Session ends → tabs re-enabled
• Duplicate session name override deletes old data
• Start button stays disabled until Load clicked
• I2C tab works after session unload

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Next Steps (If Needed)

Potential Improvements:

1. Add confirmation dialog for Unload button ("Are you sure?")
2. Add visual indicator when tabs are disabled (e.g., tooltip explaining why)
3. Add session state indicator in status bar ("Session: Loaded", "Session: Running", etc.)
4. Consider adding keyboard shortcuts (Ctrl+L for Load, Ctrl+U for Unload)

Known Good Git Commits:

• Current HEAD: Session lifecycle + UART fix (this session)
• 70eb585: Telemetry working (but UART parity broken)
• a520d8f: Port configuration corrected
• 7b67099: First commit

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Contact & Context

Project: vzug-e-hinge Test & Control System Platform: Raspberry Pi (Linux 6.17.4-arch2-1) Python: PyQt6-based desktop application Hardware: UART (command + logger) and I2C interfaces Database: SQLite (max 2GB, currently at ehinge.db)

Developer Notes:

• User prefers concise, direct communication
• No emojis unless requested
• System works on Raspberry Pi with actual hardware
• Previous session required 2-day PC uptime to maintain context
• User experienced issue where Claude "forgot everything" previously

This session was saved on: 2025-11-23 All functionality verified working at end of session.

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Code Snippets for Quick Reference

How Session Loads and Starts:

# 1. User clicks "Load Session" (session_widget.py:344)
def _on_load_clicked(self):
    # Check for duplicate session name
    # Load profiles from database
    success = self.session.load_session(...)
    if success:
        self.start_button.setEnabled(True)
        self.unload_button.setEnabled(True)
        self._disable_port_tabs()  # UART/I2C tabs disabled

# 2. User clicks "Start" (session_widget.py:444)
def _on_start_clicked(self):
    # Create worker thread
    self.worker = SessionWorker(self.session, self.db_path)
    self.worker.start()  # Opens ports and starts execution

# 3. Session ends (signal handler) (session_widget.py:582)
def _on_session_finished(self):
    self._reset_controls()
    self._cleanup_session()  # Closes ports, re-enables tabs, disables buttons

How Ports Are Closed:

# session.py:672
def _close_ports(self):
    import time
    # Close UART command port
    if self.uart_command_port:
        uart_stop_reader(self.uart_command_port)
        time.sleep(0.1)  # Let reader thread stop
        uart_close(self.uart_command_port)
        self.uart_command_port = None
    # Similar for UART logger and I2C
    time.sleep(0.2)  # Let OS release ports

How Tabs Are Disabled:

# session_widget.py:727
def _disable_port_tabs(self):
    if self.main_window:
        self.main_window.tabs.setTabEnabled(3, False)  # UART
        self.main_window.tabs.setTabEnabled(4, False)  # I2C

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END OF SESSION SUMMARY

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