CY7C964 Datasheet, PDF (1/6 Pages) Cypress Semiconductor – Bus Interface Logic Circuit

64
fax id: 5604
CY7C964
Features
• Comparators, counters, latches, and drivers minimize
logic requirements for a variety of multiplexed and
non-multiplexed buses
• Directly drives VMEbus address and data signals
• 8-bit comparator for slave address decoding
• Flexible interface optimized for VMEbus applications
• Companion device to Cypress VMEbus family of com-
ponents
• Replaces multiple SSI/MSI components
• Cascadable
• 64-pin QFP and 68-pin PGA packages
• See the VMEbus Interface Handbook for more informa-
tion
Functional Description
The CY7C964 integrates several space-consuming functions
into one small package, freeing board space for the implemen-
tation of added-value board features. It contains counters,
comparators, latches, and drivers configured to be of value to
implementors of any backplane interface with address and
data buses, particularly VMEbus interfaces. The on-chip driv-
ers are suitable for driving the VMEbus directly. The CY7C964
is ideal in applications where high-performance and real es-
tate are primary concerns.
Although having many applications, the Bus Interface Logic
Circuit is an ideal companion part to Cypress’s VMEbus family
of components, the VIC068A, VIC64, the CY7C960, and
CY7C961. It is intended to drive the address and data buses,
so three or four of these small devices are needed per control-
Bus Interface Logic Circuit
ler. In every case, the controllers provide the control and timing
signals to the Bus Interface Logic Circuit as it acts as a bridge
between the VMEbus and the Local bus.
Application with VMEbus Architecture
Use with Cypress VMEbus Controllers
The CY7C964 Bus Interface Logic Circuit is a seamless inter-
face between the VIC068A/VIC64 and the VMEbus signals.
The device functions equally well in the established 32-bit
VMEbus arena and the new 64-bit VMEbus standard. The de-
vice contains three 8-bit counters to fulfill the functions of Block
counters, and DMA counters as implied by the D64 portion of
the VMEbus specification. It also contains the necessary mul-
tiplexing logic to allow the 64-bit-wide VMEbus path to be fun-
nelled to and from the 32-bit local bus. Control circuitry is in-
cluded to manage the switching of the 32-bit address bus
during normal (32-bit) operations, and during MBLT (64-bit)
operations. The on-chip drivers are capable of driving the
VMEbus directly (48 mA).
Use in Other VMEbus Controller Implementations
The CY7C964 circuitry is designed to be of use to designers
of VMEbus circuitry, including VSB (VME subsystem bus) and
designs not requiring the features of the Cypress VIC068A,
VIC64, CY7C960, and CY7C961. The logic diagram includes
general-purpose blocks of comparators, counters, and latches
that can be controlled using the flexible control interface to
allow many different options to be implemented. Although the
device is packaged in a small 64-pin package, the use of mul-
tiplexed input and output pins provides access to the many
internal functions, thus saving external circuitry.
Pin Configuration
PQFP/CQFP/TQFP
Top View
GND
1
LD7
2
LDS
3
FC1
4
STROBE*
5
MWB*
6
LCOUT*
7
GND
8
VCOMP*
9
VCOUT*
10
LADO
11
LADI
12
LEDI
13
LEDO
14
A7
15
GND
16
48
GND
47
LD0
46
LA0
45
DENIN*
44
DENIN1*
43
LAEN
42
LCIN*
41
VCIN*
40
VCC
39
BLT*
38
D64
37
DENO*
36
ABEN*
35
D0
34
A0
33
GND
C964-1
Cypress Semiconductor Corporation • 3901 North First Street • San Jose • CA 95134 • 408-943-2600
November 1992 – Revised December 4, 1997