
RTI-20
STATUS OUTPUTS
NAME
PIN NUMBER
LCC
43
TYPE
ACTIVE
DESCRIPTION
PGA
F9
RCS
TO
AL
RAM Chip Select. Active low output used to
enable memory for access.
RAM Read/Write. High output enables memory
read, low output enables memory write, used in
conjunction with RCS). Normally high output.
Command Strobe. COMSTR is an active low
output of 500ns duration identifying receipt of a
valid command.
Fail-safe Timer. The TIMERON output pulses
low for 730ms when the RTI begins transmit-
ting (i.e., rising edge of STATUS) to provide a
fail-safe timer meeting the requirements of
MIL-STD-1553B. This pulse is reset when
COMSTR goes low or during Master Reset. in
the external self-test mode TIMERON does not
recognize COMSTR and resets after 730ms.
Message Error. The active high MES ERR out-
put signals that the Message Error bit in the Sta-
tus Register has been set due to receipt of an
invalid command or an error during message
sequence. MES ERR will reset to logic zero on
receipt of next valid command.
Channel A/B. Output identifying the channel on
which the most recent valid command was
received. Channel A = 1, Channel B = 0.
Transmit. Active low output identifies a
transmit command message transfer by the RTI
is in progress.
Receive. Active low output identifies a receive
command message transfer by the RTI is in
progress.
Broadcast. BRDCST is an active low output
that identifies receipt of a valid broadcast com-
mand.
Status. Active high output pulse indicating that
the RTI is in the process of transmitting a status
word.
RRD/RWR
45
E11
TO
--
COMSTR
22
J6
TO
AL
TIMERON
41
G11
TO
AL
MES ERR
49
D10
TO
AH
CH A/B
26
L6
TO
--
XMIT
38
H11
TO
AL
RCV
51
B11
TO
AL
BRDCST
36
J11
TO
AL
STATUS
23
J7
TO
AH