Real Time Devices AD1200 User Manual page 121

intef
82C55A
Output Control Slgnal Deflnlilon
OEF lOutpur Buftcr Fu[ F/F). The 6BF output wil
go "low" to indicate that the CPU has written data
out to the specified port. The ffi
f n wiil be set bv
the rising edge of the WF input and reset by ffi
Input being low.
FR (lctnowledge Input). A "low" on this input
informs the 82C55A that the data from port A or port
B has been acceptsd. In essenc€, a response from
the peripheral device indicating that it has received
the data output by the cPU.
INTR (lnterrupt Request). A "high','on this output
can be used to intenupt the CpU when an output
device has accepted data transmitted bv the CpU.
INTR is set when Affi is a ,,on€", 6EF-is a ,,on€"
gl INTE is a "on€". lt is reset by the falling edge of
wR.
ITiITE A
Gontrolled by bit set/reset of pG5.
INTE B
Controlled by bit set/reset of pC2.
231256-16
Flgurc 11. IIODE 1 (Strobcd Output)
oiltiottlotD
dl^
E^
lffie
ilh
eh
Itfrq
231256-r5
r - - . r
I ltrl
I
l A l
mE I FOtt]
oof{ttol toRD
Flgure l0.llODE I Outpur
3-135