Heathkit H9 Manual page 25

-
Pag ez s
@
PIN #
DATA
DESCRIPTION
17
72
13
74
15
16
77
18
B
B
B
B
B
B
B
B
t1
t2
t3
t4
t5
t6
t7
t8
Parallel
Input
o Positive true logic.
o High Level Input Voltage (Vr") : 2 V min.
o Low Level Input Voltage (Vrr) : 0.8 V max.
. Low Level Input Current (Irr) : -2OO p"A max. @
o.4 vL.
o Standard 74L5244 input buffer.
19
mAv;
Data Taken
. Reset Output Data Available - Normally high.
o The external device will pull this line low
to indicate to the Terminal that it has
received the data. The Terminal will not
send new data until n-Dffz, has returned high.
o High Level Input Voltage (Vnt) : 2 V min.
o Low Level Input Voltage (Vrr) : 0.8 V max.
. Low Level Input Current (Irr) : 2.8 mA max.
. Refer to the "Handshake Timing" section.
20
DAV;
Data Sent
. Input Data Available - Normall5r high. The
external device will pull this line low to
indicate that there is data ready to be
inputted to the parallel input.
o High Level Input Voltage (Vrrr) : 2 V min.
o Low Level Input Voltage [Vrr,) : 0.8 V max.
o Low Level Input Current (Irr) : 1.8 mA max.
o Refer to the "Handshake Timing" section.
27
m-AV,
Data Received
. Reset Input Data Available -
Normally high. The
Terminal sends a negative-going pluse (:
25 p,S
wide) on this line to indicate to the external device
that the Terminal has received and is finished with
the data.
o High Level Output Voltage (Vo") : 2.7 V min.
@ -+oo pA (Ior).
. Low Level Output Voltage (Vor) : 0.4 V max.
@ 4 mA (Ior).
. Refer to the "Handshake Timing"
section.
22
23
24
Ground