ATF16V8B-25JI ATMEL [ATMEL Corporation], ATF16V8B-25JI Datasheet - Page 6

• Manufacturer Part Number: ATF16V8B-25JI
• Description: High Performance Flash PLD
• Manufacturer: ATMEL [ATMEL Corporation]

Input Diagram
Electronic Signature Word
There are 64 bits of programmable memory that are al-
ways available to the user, even if the device is secured.
These bits can be used for user-specific data.
Programming/Erasing
Programming/erasing is performed using standard PLD
programmers. See CMOS PLD Programming Hardware &
Software Support for information on software/program-
ming.
Functional Logic Diagram Description
The Logic Option and Functional Diagrams describe the
ATF16V8B architecture. Eight configurable macrocells
can be configured as a registered output, combinatorial
I/O, combinatorial output, or dedicated input.
The ATF16V8B can be configured in one of three different
modes. Each mode makes the ATF16V8B look like a dif-
ferent device. Most PLD compilers can choose the right
mode automatically. The user can also force the selection
by supplying the compiler with a mode selection. The de-
termining factors would be the usage of register versus
combinatorial outputs and dedicated outputs versus out-
puts with output enable control.
The ATF16V8B universal architecture can be pro-
grammed to emulate many 20-pin PAL devices. These
Compiler Mode Selection
Note:
1-12
ABEL, Atmel-ABEL
CUPL
LOG/iC
OrCAD-PLD
PLDesigner
Tango-PLD
1. Only applicable for version 3.4 or lower.
ATF16V8B
Registered
P16V8R
G16V8MS
GAL16V8_R
“Registered”
P16V8R
G16V8R
(1)
Complex
P16V8C
G16V8MA
GAL16V8_C7
“Complex”
P16V8C
G16V8C
I/O Diagram
Input and I/O Pull-Ups
All ATF16V8B family members have internal input and I/O
pull-up resistors. Therefore, whenever inputs or I/Os are
not being driven externally, they will float to V
sures that all logic array inputs are at known states.
These are relatively weak active pull-ups that can easily
be overdriven by TTL-compatible drivers (see input and
I/O diagrams below).
architectural subsets can be found in each of the configu-
ration modes described in the following pages. The user
can download the listed subset device JEDEC program-
ming file to the PLD programmer, and the ATF16V8B can
be configured to act like the chosen device. Check with
your programmer manufacturer for this capability.
Unused product terms are automatically disabled by the
compiler to decrease power consumption. A Security
Fuse, when programmed, protects the content of the
ATF16V8B. Eight bytes (64 fuses) of User Signature are
accessible to the user for purposes such as storing project
name, part number, revision, or date. The User Signature
is accessible regardless of the state of the Security Fuse.
(1)
Simple
P16V8AS
G16V8AS
GAL16V8_C8
“Simple”
P16V8C
G16V8AS
(1)
Auto Select
P16V8
G16V8A
GAL16V8
GAL16V8A
P16V8A
G16V8
CC
. This en-