AN214 Philips, AN214 Datasheet - Page 12

• Manufacturer Part Number: AN214
• Description: 74F Extended Octal-Plus Family Applications
• Manufacturer: Philips

Philips Semiconductors
Dual-Registered Transceiver Applications
Figure 13 illustrates how the 74F646A-649A and 74F651A-654A can
be used to either synchronize data transfer between two systems, or
pipeline data. Data is stored in a register, then, while retrieving more
data, the first data is read. When the second is available, it can
either be stored or read directly. Two slower systems can be
multiplexed into a high speed system in the same way.
June 1988
74F extended octal-plus family applications
ODD/EVEN
CPAB
OEAB
GND
SAB
A0
A1
A2
A3
A4
A5
A6
A7
10
12
11
1
2
3
4
5
6
7
8
9
74F280B 9-BIT COMPARATOR
Figure 13. 74F Extended Octal-Plus Dual-Registered Transceiver Applications
24
23
22
21
20
19
18
17
16
15
14
13
V
CPBA
SBA
OEBA
B0
B1
B2
B3
B4
B5
B6
B7
CC
Figure 14. 74F657 Parity Bus Transceiver Applications
T/R
12
B0
B1
B2
B3
B4
B5
B6
B7
PARITY
ERROR
8L
OR
Parity Bus Transceiver Applications
Figure 14 illustrates the functional density advantages of the Parity
Bus Series using the 74F657 in a typical microprocessor/data bus
transceiver application. Note the 74F245 + 74F280B version would
still require a 2-input AND gate and 3-State buffers for the PARITY
and ERROR outputs. And, of course, it would require an order of
magnitude higher input current than a single 74F657 would, and
would also introduce much higher capacitive loading (for both the
bus and the microcontroller).
10
12
11
1
2
3
4
5
6
7
8
9
OR
24
23
22
21
20
19
18
17
16
15
14
13
8L
8L
8L
10
12
10
12
11
11
1
2
3
4
5
6
7
8
9
1
2
3
4
5
6
7
8
9
ODD/EVEN
ERROR
T/R
24
23
22
21
20
19
18
17
16
15
14
13
24
23
22
21
20
19
18
17
16
15
14
13
8L
8L
Application note
AN214
SF01340
SF01341
PARITY
B0
B1
B2
B3
B4
B5
B6
B7