ATF1508ASVL ATMEL [ATMEL Corporation], ATF1508ASVL Datasheet - Page 5

• Manufacturer Part Number: ATF1508ASVL
• Description: Highperformance EE PLD
• Manufacturer: ATMEL [ATMEL Corporation]

Figure 1. ATF1508ASV(L) Macrocell
Output Select and Enable
The ATF1508ASV(L) macrocell output can be selected as
registered or combinatorial. The buried feedback signal can
be either combinatorial or registered signal regardless of
whether the output is combinatorial or registered.
The output enable multiplexer (MOE) controls the output
enable signals. Any buffer can be permanently enabled for
simple output operation. Buffers can also be permanently
disabled to allow use of the pin as an input. In this configu-
ration. all the macrocell resources are still available,
including the buried feedback, expander and CASCADE
logic. The output enable for each macrocell can be
selected as one of the global OUTPUT enable signals. The
device has six global OE signals.
Global Bus/Switch Matrix
The global bus contains all input and I/O pin signals as well
as the buried feedback signal from all 128 macrocells.
The switch matrix in each logic block receives as its inputs
all signals from the global bus. Under software control, up
to 40 of these signals can be selected as inputs to the logic
block.
Foldback Bus
Each macrocell also generates a foldback product term.
This signal goes to the regional bus and is available to 16
macrocells. The foldback is an inverse polarity of one of the
macrocell’s product terms. The 16 foldback terms in each
region allow generation of high fan-in sum terms (up to 21
product terms) with little additional delay.
Open-collector Output Option
This option enables the device output to provide control
signals such as an interrupt that can be asserted by any of
the several devices.
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