Rainbow Electronics ATF20V8CQZ - Manual (Page 5)

5
ATF20V8C Family
0408H–04/01
Registered Mode
PAL Device Emulation/PAL Replacement
The registered mode is used if one or more registers are
required. Each macrocell can be configured as either a reg-
istered or combinatorial output or I/O, or as an input. For a
registered output or I/O, the output is enabled by the OE
pin, and the register is clocked by the CLK pin. Eight prod-
uct terms are allocated to the sum term. For a combinato-
rial output or I/O, the output enable is controlled by a
product term, and seven product terms are allocated to the sum term. When the macrocell is configured as an input,
the output enable is permanently disabled.
Any register usage will make the compiler select this mode.
The following registered devices can be emulated using
this mode:
20R8
20RP8
20R6 20RP6
20R4 20RP4
Registered Mode Operation