Additional Ram; Additional I/O; Keyboard - AMSTRAD CPC464 User Manual

1.5.2) Additional RAM

Additional RAM can be switched in place of any part of the on-board RAM. The address arbitration
and bank selection logic will be contained in a module connected to the expansion bus, but all the
signals required are brought to the expansion bus. This memory will be read-only and a special
scheme involving I/O mapping will be required to write to this additional RAM from the computer.

1.5.3) Additional I/O

Most I/O port addresses are reserved by the computer, in particular addresses below 7Fxx should not
be used at all. The following can be used by external hardware.
F8xx, F9xx, FAxx, FBxx
Expansion bus peripherals must decode addresses on A0 to A7 whilst address
bus I/O channels in the address range F800 to FBFF are reserved as follows:-
Addresses A0-A7
00 – 78 ** Do not use **
7C – 7F Reserved for disk interface
80 – BB ** Do not use **
BC – BF Reserved for future use
C0 – DB ** Do not use **
DC-DF Reserved for communications interfaces
E0-FF Available for user peripherals
Note that Z80 instructions which place the B register on the upper half of the address bus (A15-A8)
must be used.

2) Keyboard.

A full reset is operated by
or cursor movement will auto-repeat under firmware control, excluding all keys on the numeric
keypad..
Suspends program execution. Followed by a further
[ESC]
any other character resumes program execution.
is a toggle, operated by the caps lock key. Shift lock is a toggle operated by
[CAPS LOCK]
[CTRL][CAPS LOCK]
The copy cursor is detached from the input cursor by operating
keys. Input can be obtained from the character beneath the copy cursor by pressing the [COPY] key.
The cursor keys are intended to allow editing of the input buffer, which may spread over a number of
screen lines. The cursor keys may be used to position the start of keyboard input to any screen
position prior to any keyboard input being received. Once any keyboard input has been received then
the screen position is fixed. The new input text will overwrite any existing content on the screen at
that position.
[DEL] is a backwards delete and
[CTRL][SHIFT][ESC]
pressed together.
is a forward delete.
[CLR]
pressed together. Keys causing printing characters
terminates execution. Followed by
[ESC]
[SHIFT]
A10
is low. Expansion
together with the cursor