What Are Peeks & Pokes and How Do You Use Them in MSX Emulators?

Updated

A peek reads the current value stored at a memory address; a poke writes a new value to that address. In MSX emulators, pokes are the manual, low-level way to change game state — infinite lives, extra money, unlocked items — while built-in emulator cheats are pre-packaged shortcuts that often do the same thing with less typing. CheatMSX lists a small set of Peeks & Pokes (7 entries in its statistics) alongside a much larger library of 364 emulator cheats, so the section is best treated as a reference for specific titles rather than a general-purpose cheat list.

Peek vs. poke: the core mechanic

Memory in an MSX machine (and in the emulator recreating it) is a numbered sequence of addresses, each holding one byte. A cheat works by finding the address that controls the thing you want to change.

  • Peek — read the byte at an address. Used to find the right address: you peek, note the value, let the game change it (lose a life, spend gold), peek again, and see which address moved.
  • Poke — write a byte to an address. Used to apply the cheat once the address is known.

A typical entry looks like an address plus a value, for example POKE &HD5A0,&HFF — write hex FF to address D5A0. The &H prefix is MSX BASIC notation for hexadecimal; some listings use $ or a plain 0x instead.

Peeks & Pokes vs. emulator cheats: which to use

Peeks & Pokes Emulator cheats
Form Address + value you enter yourself Named, pre-built patch
Effort Manual entry, may need trial and error Usually one toggle
Flexibility Works when no cheat file exists Limited to what's been made
Risk Wrong address can freeze or corrupt the game Lower, already tested
CheatMSX count 7 364

Use a poke when a game has no ready-made cheat, when you want to change something specific the cheat file doesn't cover, or when you're learning how the game stores its data. Use the built-in cheat list when one exists for your title — it's faster and less likely to crash the emulator.

Finding and reading the Peeks & Pokes section on CheatMSX

CheatMSX organizes content by category in its main navigation and statistics panel. The Peeks & Pokes category sits alongside Emulator Cheats, Cheats, Maps, Walkthroughs, IPS Patches, Manuals, and Online Password Generators.

  1. Open CheatMSX.com.
  2. Go to the Peeks & Pokes category (listed in the site statistics as "7 Peeks & Pokes").
  3. Browse or use the A–Z index to find your game title.
  4. Read the entry: it gives a memory address and the value to write, usually in hex.

Note that the site requires JavaScript and asks visitors to disable ad/script blockers to view some pages, so a blocked script can leave a category looking empty.

Applying a poke in an MSX emulator

Exact menu names differ between emulators (blueMSX, openMSX, fMSX, and others), but the workflow is the same:

  1. Load the game and get to a state where the cheat should apply (in-game, not the title screen).
  2. Open the emulator's memory editor or debugger. Most MSX emulators expose a memory view or a "poke"/cheat console.
  3. Enter the address from the CheatMSX listing, matching the number base the tool expects (hex or decimal).
  4. Enter the value from the listing.
  5. Write the byte and return to the game.
  6. Verify — check that the effect appears (lives count, gold, etc.). If nothing changes, the address may be for a different ROM revision.

Some emulators also accept a poke through a built-in BASIC prompt or a cheat-file format, which lets you save the entry for reuse instead of retyping it each session.

Common problems and how to read them

  • Nothing happens. The address is likely correct for a different version or region of the ROM. MSX games were often re-released with shifted memory layouts.
  • The game freezes or glitches. You poked the wrong address or the wrong value. Reload a save state and try again; avoid poking addresses you haven't confirmed with a peek.
  • Hex vs. decimal confusion. A value of 255 and FF are the same byte. If the emulator expects decimal and you type FF, it will reject or misread it. Convert before entering.
  • Value too large. A single address holds one byte (0–255 decimal, 00–FF hex). Larger numbers need more than one address.
  • Emulator compatibility. A poke written for one emulator's memory map may not match another if the machine model (MSX1, MSX2, MSX2+) differs. Match the model the listing was made for.

Because CheatMSX's Peeks & Pokes collection is small, expect to rely on the emulator cheat list for most titles and treat pokes as the fallback when no cheat exists.