Fig. 4-7: Example of a two-circuit synchronization scheme
4.4.2.2. What gives an independent resolution to the outputs of the high and low
byte?
One of the important practical examples is a system of 3 buses with a width of 8 bits each, as
shown in the figure below. The first bus is the input one, the second is the output bus, the third is bi-
directional.
Fig. 4-8: Example of a grouped connection of digital lines: three buses of 8 bits each.
The example shows an almost important case of implementing interfaces with various devices
that have an 8-bit bidirectional data bus, input and output control lines. It should be noted that DI14,
DI15, DI16 inputs have alternative synchronization functions (
).
CON
V_
OUT
START
_OUT
CON
V_
IN
DGN
D
DGN
D
START
_IN
DGN
D
DGN
D
E-502 #3
CON
V_
OUT
START
_OUT
CON
V_
IN
DGN
D
DGN
D
START
_IN
DGN
D
DGN
D
CON
V_
OUT
START
_OUT
CON
V_
IN
DGN
D
DGN
D
START
_IN
DGN
D
DGN
D
E-502 #1
(
ведущий
)
(
ведомый для
#1
,
ведущий для
#3
, #
4
)
(
ведомый
)
CON
V_
OUT
START
_OUT
CON
V_
IN
DGN
D
DGN
D
START
_IN
DGN
D
DGN
D
E-502 #4
(
ведомый
)
E-502 #2
Цепь
1
Цепь
2
DI1...DI8
DO1...DO8
DI9...DI16
DO9...DO16
8
бит
8
бит
E-502
8
бит
(
slave for #1, master
for #3, #4)
(
master)
Circuit 2
Circuit 1
(
slave)
(
slave)
8 bits
8 bits
8 bits