Commodore Amiga A500 Technical Reference Manual page 30

Expansion
Notes
1 )
The loading, buffering and layout requirements specified for the
A1 000/A500
expansion connector must be strictly followed for
reliable operation. Unbuffered devices and bus line extension are
known problem areas.
2) Unbuffered daisy-chaining of multiple external expansion devices
is not supported.
3)
The
A500
provides only nominal amounts of power for expan-
sion devices.
All
devices having significant power requirements
are expected to be self-powered and should not make connec-
tions to the power pins on the expansion connector.