Review PicoCalc Code

Evaluate MicroPython code for the PicoCalc embedded platform. Check for correctness, safety, and pattern compliance.

Review Checklist

Memory Management

• gc.collect() called at app start in main()
• Large data uses bytearray not list where possible
• Key buffer pre-allocated as bytearray(10), not created per-read
• No unbounded list/dict growth in main loop
• Modules cleaned up if loaded dynamically

Hardware Safety

• I2C reads wrapped in try/except OSError
• PWM audio stopped (duty_u16(0)) in cleanup/exit path
• Display cleared (fill(0); show()) on exit
• No keyboard reset (_REG_RST) during initialization
• SPI buses not conflicting (display=SPI1, SD=SPI0)
• PWM objects created once, not recreated in loops

Application Structure

• Class-based with __init__, run, handle_input, draw
• ESC key (b'\x1b\x1b') exit path back to menu
• main() function as standalone entry point
• if __name__ == "__main__": main() guard
• Top-level try/except with sys.print_exception(e)
• Uses utime (not time) for ticks_ms/ticks_diff/sleep_ms
• Uses urandom (not random) for random numbers

Display Correctness

• Colors are 4-bit grayscale (0-15), not RGB
• show() called after drawing operations
• Coordinates within 0-319 range
• Text accounts for 6x8 font (53 cols x 40 rows)
• Avoids fill(0) in draw loop — use static+animate, erase-move-draw, or overwrite patterns instead
• beginDraw()+fill(0) only for one-time initial draws, NOT every frame
• Does NOT call fill(0); show() on exit — just returns to menu
• Static screens drawn once, only animated elements update per frame

Input Handling

• Reads via picocalc.terminal.readinto(key_buffer)
• Checks if not count: return for no-key case
• Matches escape sequences as bytes not individual chars
• Handles None return from readinto

Network Safety (if applicable)

• WiFi/BLE operations wrapped in try/except
• Interface reset pattern for recovery
• Credentials not hardcoded (use wifi.json)
• gc.collect() before/after network operations

Common Mistakes

Mistake	Correct
import time; time.ticks_ms()	import utime; utime.ticks_ms()
import random; random.randint()	import urandom; urandom.randint()
RGB color 0xFF0000	Grayscale 0-15
Drawing without show()	Always call show() after draw cycle
time.sleep(1) blocking loop	utime.ticks_diff() for timing
Creating bytearray(10) per frame	Pre-allocate in __init__

Additional Resources

• references/memory-checklist.md - Memory patterns
• references/hardware-safety.md - Hardware safety with examples
• references/app-structure-checklist.md - Pattern compliance