Rainbow Electronics ATF20V8BQL - Manual (Page 9)

ATF20V8B(Q)(L)
9
ATF20V8B Complex Mode
PAL Device Emulation/PAL Replacement. In the complex
Mode, combinatorial output and I/O functions are possible.
Pins 1 and 11 are regular inputs to the array. Pins 13
through 18 have pin feedback paths back to the AND-array,
which makes full I/O capability possible. Pins 12 and 19
(outermost macrocells) are outputs only. They do not have
input capability. In this mode, each macrocell has seven
product terms going to the sum term and one product term
enabling the output. Combinatorial applications with an OE requirement will
make the compiler select this mode. The following devices
can be emulated using this mode:
20L8
20H8
20P8
Complex Mode Operation
ATF20V8B Simple Mode
PAL Device Emulation/PAL Replacement. In the Simple
Mode, 8 product terms are allocated to the sum term. Pins
15 and 16 (center macrocells) are permanently configured
as combinatorial outputs. Other macrocells can be either
inputs or combinatorial outputs with pin feedback to the
AND-array. Pins 1 and 11 are regular inputs.
The compiler selects this mode when all outputs are combi-
natorial without OE control. The following simple PALs can
be emulated using this mode:
14L8 14H8 14P8
16L6 18H6 16P6
18L4 18H4 18P4
20L2 20H2 20P2
Simple Mode Option