Specifications

. Figure 9.5 M785 Unibus Drivers and Receivers
A00 is used for byte control. A01 and A02 are decoded to provide one of
four addresses. A < 1203 > are determined by jumpers on the card. When
the jumper is in, the selector will look for a 0 on that address line-
A < 17:13 > must all be l’s-(this defines the external bank). Other bus
inputs to the selector are C < 1:0 > and MSYN. The single bus output is
SSYN. The user signals are SELECT 0. 2, 4, and 6 (corresponding to the
decoding of A02 and AOl, one of which is asserted when A < 17:13 > are all-
l’s and A < 12:03 > compare with the state of the jumpers. Other user sig-
nals are OUT HIGH (gate data into high byte), OUT LOW (gate data into low
byte), and IN (gate data onto the bus). The equations for these last three
signals are as follows:
.
OUT HIGH =
DATO + DATOB;AOO
OUT LOW =
DATO + DATOB*m
IN
= DATI + DATIP
where “+” means a logical or and “*” means a logical and.
Use of the M105, drivers, receivers and a flip-flop register is shown in- Fig
ure 9-7.
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