CPU Speed control

Acceleration, or Turbo mode, allows the Next to run at faster clock speeds than a standard Spectrum.

Acceleration is enabled via NextReg:$06 and configured via NextReg:$07, or via a user control. There are four potential settings:

• Turbo off, or turbo on and $07 set to #00: 3.5 Mhz (standard clock).
• Turbo on, $07 set to #01: 7 Mhz (x2). (Standard for Pentagon).
• Turbo on, $07 set to #10: 14 Mhz. (x4)
• Turbo on, $07 set to #11: 28 Mhz. (x8) Some features, such as Layer 2 drawing, are disabled at this speed.