Function-Setting - Radio Shack Tandy 200 Technical Reference Manual

Function
Outline
82C51A's
functional configuration
is
programmed
by
the software.
Operation between
82C51A
and
CPU
is
executed by program
control,
Tabte
C-6
shows
the operation
between
CPU
and
the device.
cs
C/D
RD
WR
1
X
X
X
Data bus
3-state
X
1
1
Data bus
3-state
1
1
Status
- CPU
1
1
Control
word
*-
CPU
1
Data
-*
CPU
1
Data
«-
CPU
Table
C-6.
Operation between 82C51A and
CPU
It
is
necessary
to
execute a
function-setting
sequence
after resetting
on
82C51A.
Figure
C-13
shows
the
function-setting
sequence.
If
the function
was
set,
the device
is
ready
to
receive a
command,
thus enabling
the transfer of
data by
setting
a necessary
command,
reading
a
status
and
reading/writing data.
C-23