Rainbow Electronics ATF20V8CQZ - Manual (Page 7)

7
ATF20V8C Family
0408H–04/01
Complex Mode
PAL Device Emulation/PAL Replacement
In the Complex Mode, combinatorial output and I/O func-
tions 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
Simple Mode
PAL Device Emulation/PAL Replacement
In the Simple Mode, eight product terms are allocated to
the sum term. Pins 15 and 16 (center macrocells) are per-
manently configured as combinatorial outputs. Other mac-
rocells 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