PEEL22CV10 ETC, PEEL22CV10 Datasheet - Page 4

• Manufacturer Part Number: PEEL22CV10
• Description: CMOS Programmable Electrically Erasable Logic Device
• Manufacturer: ETC

enable term will permanently enable the output buffer and
yield a dedicated output. Conversely, if every connection is
intact, the enable term will always be logically false and the
I/O will function as a dedicated input.
Input/Feedback Select
When configuring an I/O macrocell to implement a regis-
tered function (configurations 1 and 2 in Figure 5), the Q
output of the flip-flop drives the feedback term. When con-
figuring an I/O macrocell to implement a combinatorial
function (configurations 3 and 4 in Figure 5), the feedback
signal is taken from the I/O pin. In this case, the pin can be
used as a dedicated input or a bi-directional I/O. (Refer
also to Table 1.)
Additional Macro Cell Configurations
Besides the standard four-configuration macrocell shown in
Figure 5, each PEEL™22CV10A provides an additional
eight configurations that can be used to increase design
flexibility. The configurations are the same as provided by
the PEEL™18CV8 and PEEL™22CV10AZ. However, to
maintain JEDEC file compatibility with standard 22V10
PLDs the additional configurations can only be utilized by
specifying the PEEL™22CV10A+ for logic assembly and
programming. To reference these additional configurations
please refer to the PEEL™22CV10A+ specifications at the
end of this data sheet.
Figure 4. Block Diagram of the PEEL™ 22CV10A I/O Macrocell.
4 of 10
Design Security
The PEEL™22CV10A provides a special EEPROM secu-
rity bit that prevents unauthorized reading or copying of
designs programmed into the device. The security bit is set
by the PLD programmer, either at the conclusion of the pro-
gramming cycle or as a separate step after the device has
been programmed. Once the security bit is set, it is impos-
sible to verify (read) or program the PEEL™ until the entire
device has first been erased with the bulk-erase function.
Signature Word
The signature word feature allows a 24-bit code to be pro-
grammed
PEEL™22CV10A+ software option is used. The code can
be read back even after the security bit has been set. The
signature word can be used to identify the pattern pro-
grammed into the device or to record the design revision,
etc.
into
the
PEEL™22CV10A
PEEL
TM
22CV10A
04-02-009F
if
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