PALCE20V8H-25PC/4 Lattice Semiconductor, PALCE20V8H-25PC/4 Datasheet - Page 7

• Manufacturer Part Number: PALCE20V8H-25PC/4
• Description: EE CMOS 24-Pin Universal Programmable Array Logic
• Manufacturer: Lattice Semiconductor

Power-Up Reset
All flip-flops power up to a logic LOW for predictable system initialization. Outputs of the
PALCE20V8 depend on whether they are selected as registered or combinatorial. If registered is
selected, the output will be HIGH. If combinatorial is selected, the output will be a function of
the logic.
Register Preload
The register on the PALCE20V8 can be preloaded from the output pins to facilitate functional
testing of complex state machine designs. This feature allows direct loading of arbitrary states,
making it unnecessary to cycle through long test vector sequences to reach a desired state. In
addition, transitions from illegal states can be verified by loading illegal states and observing
proper recovery.
Security Bit
A security bit is provided on the PALCE20V8 as a deterrent to unauthorized copying of the array
configuration patterns. Once programmed, this bit defeats readback and verification of the
programmed pattern by a device programmer, securing proprietary designs from competitors.
The bit can only be erased in conjunction with the array during an erase cycle.
Electronic Signature Word
An electronic signature word is provided in the PALCE20V8. It consists of 64 bits of
programmable memory that can contain any user-defined data. The signature data is always
available to the user independent of the security bit.
Programming and Erasing
The PALCE20V8 can be programmed on standard logic programmers. It also may be erased to
reset a previously configured device back to its unprogrammed state. Erasure is automatically
performed by the programming hardware. No special erase operation is required.
Quality and Testability
The PALCE20V8 offers a very high level of built-in quality. The erasability of the device provides
a direct means of verifying performance of all AC and DC parameters. In addition, this verifies
complete programmability and functionality of the device to provide the highest programming
and post-programming functional yields in the industry.
Technology
The high-speed PALCE20V8H is fabricated with Vantis’ advanced electrically erasable (EE) CMOS
process. The array connections are formed with proven EE cells. Inputs and outputs are
designed to be compatible with TTL devices. This technology provides strong input clamp
diodes, output slew-rate control, and a grounded substrate for clean switching.
PCI Compliance
PALCE20V8H devices in the -5/-7/-10 speed grades are fully compliant with the PCI Local Bus
Specification published by the PCI Special Interest Group. The PALCE20V8H’s predictable timing
ensures compliance with the PCI AC specifications independent of the design. On the other
hand, in CPLD and FPGA architectures without predictable timing, PCI compliance is dependent
upon routing and product term distribution.
PALCE20V8 Family
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