## Clock

### Clock:

AppleWin emulates a No-Slot clock (aka NSC).

This is a chip (a Dallas SmartWatch DS1216) that sits under one of the 28-pin ROM chips in the Apple II.
No hardware configuration is required: this chip is always present, but won't interfere with emulation when not in use.

It requires a software driver to be installed (for DOS and ProDOS). This driver then emulates the Thunderclock card.

Here's a summary of NSC/ROM chip locations and which drivers work:

- "CD" ROM socket: C000-DFFF (internal) ROM space - all drivers work
- "EF" ROM socket: E000-FFFF ROM space - never seen any drivers use this space
- "CF" ROM socket: C000-FFFF (internal) ROM space - all drivers work
- Slot ROM socket: Cs00-CsFF (slot) ROM space - NS.CLOCK.SYSTEM works

Here are the drivers and ROM pages they check:

- ProDOS "SWU.SYSTEM" - internal C3
- ProDOS "NS.CLOCK.SYSTEM" - internal C3 C8 / external C1-C7
- GEOS "NoSlot Clock" - internal C8

NOTE: For ProDOS, the load order of drivers is important:

Some .SYSTEM drivers will not chain-load the next driver.
NS.CLOCK.SYSTEM does, so ensure this is the first one ProDOS finds, whereas ZIP.SYSTEM doesn't so put this at the end of the chain.