Commodore Amiga A500 Technical Reference Manual page 8

Mouse and Joystick
Ports
A500 Expansion Port
A500 RAM Expansion
A500 Power Supply
Connector
stead of the A1000. An A500 genlock will also have to supply its
own power. Power will not be provided for the Genlock. All signals
on the 23 pin connector are the same except for the power.
In addition to the 23 pin video connector, the A500/B2000 provides
a monochrome composite video output, unlike the A1000. This pro-
vides the capability of using a low-cost, high persistence mono-
chrome monitor with the A500 for viewing 640 x 400 interlaced
video without as much flickering.
Power is provided for the A520 modulator and composite video
adapter.
The mouse and joystick ports of the A500 and A2000 are identical
to the A1000, except that the current limiting protection circuitry
has been eliminated. The A500 and A2000 use a different mouse
than the one the A1000 uses. A diagram and information on this
mouse is included in Appendix A of this manual.
The expansion port is electrically compatible with the A1000, but
because of its physical location, it cannot accept any A1000
expansion peripherals without some further adapter. Power is
supplied to this connector, but only enough for a ROM cartridge.
The exact pinout of this 86 pin edge connector appears later in this
document,in the section of Amiga expansion. The A500 diagram in
Appendix A shows the new positioning of this port (relative to
A1000) and the pin numbers.
Associated with the built-in 512KB of RAM is a header socket to al-
low an additional 512KB of RAM and a battery backed-up real time
clock board to be added. This small PCB (the A501 RAM Expansion
Cartridge) can easily be installed by the user. The clock in this unit
functions the same as that built into the A2000, which is reviewed
in Section 7-1.
The A500 power supply connector is similar to that of the C128.
The pinout of the square 5 pin DIN connector is as follows:
PIN SIGNAL
1 + 5Vdc @ 4.3A
2 Shield Ground
3 + 12Vdc@ 1.0A
4 Signal Ground
5 -12Vdc @ .1A
5