Use the Spectrum 128 style menu below to navigate to the various sections detailing the keypad.

Keypad Main Menu Title
View History Of The Keypad
View Appearance Of The Keypad
View Editing Functions Available Via The Keypad
View Method Of Operation
View Communication Details
View Timing Details
View Hardware Details
View Software Details
View Details About Building A Compatible Keypad

Editing Functions

The keypad circuitry is based around a PIC1652 microcontroller and communicates serially with the Spectrum 128 via the KEYPAD socket. The Spectrum 128 has additional software built into the 48K BASIC ROM (ROM 1) which polls this socket periodically and interprets any codes received from it. These codes are then passed on to the EDITOR ROM (ROM 0) which performs the appropriate editing function. The keypad is only scanned when in 128K mode and so the extra editing functions are not available when in 48K BASIC. The keypad keys can be used for the following: selecting items from the main pop up menu, editing a program when in 128 BASIC mode, selecting items from the 128 BASIC pop-up menu and for entering data and arithmetic operators in Calculator mode. Note that once in calculator mode the keypad can not be used for selecting items from the Calculator mode pop-up menu. The keypad performs no function when in Tape Loader or Tape Tester modes. When negotiating menus with the keypad only the UP, DOWN and ENTER keys can be used.

The menu below provides links to see the editing functions available when in 128K BASIC mode. These functions are in fact available from the normal keyboard via certain key press combinations and the menu also allows these to be viewed.

Editing Functions Menu Title
Views New Keypad Editing Functions
Views Editing Functions Available Via Keyboard
Views New Key Codes Generated By The Keypad

The keypad can also be used as a games controller and this is why the UP, DOWN, LEFT and RIGHT cursor keys are coloured red and why red dots appear on the 0 and ENTER keys as these denote the two fire buttons. The 0 (SHIFT) and ENTER keys are larger than the other keys on the keypad and so this could explain why these keys were chosen for the fire buttons.

The Spectrum 128 Introduction manual describes the editing functions available via the keypad.