ATF1504ASV/ATF1504ASVL
All power-down AC characteristic parameters are com-
When the Large hysteresis option is active, ICC is
reduced by several hundred microamps as well.
puted from external input or I/O pins, with
reduced-power bit turned on. For macrocells in
Reduced-Power mode (reduced-power bit turned on),
the reduced-power adder, tRPA, must be added to the
AC parameters, which include the data paths tLAD,
tLAC, tIC, tACL or tACH, tEN and tSEXP.
Details on the power Reset hysteresis feature are avail-
able in the “ATF15XX Power-on Reset Hysteresis Fea-
ture” application note.
Security Fuse Usage
The ATF1504ASV(L) macrocell also has an option
whereby the power can be reduced on a per macrocell
basis. By enabling this power-down option, macrocells
that are not used in an application can be turned down,
thereby reducing the overall power consumption of the
device. This option is automatically set by the device
fitter software.
A single fuse is provided to prevent unauthorized copy-
ing of the ATF1504ASV(L) fuse patterns. Once pro-
grammed, fuse verify is inhibited. However, the 16-bit
User Signature remains accessible.
Programming
Each output also has individual slew rate control. This
may be used to reduce system noise by slowing down
outputs that do not need to operate at maximum speed.
Outputs default to slow switching, and may be specified
as fast switching in the design software or design file.
ATF1504ASV(L) devices are in-system programmable
(ISP) devices utilizing the 4-pin JTAG protocol. This
capability eliminates package handling normally
required for programming and facilitates rapid design
iterations and field changes.
Microchip provides ISP hardware and software to allow
programming of the ATF1504ASV(L) via the PC. ISP is
performed by using either a download cable, a compa-
rable board tester or a simple microprocessor interface.
Design Software Support
ATF1504ASV(L) designs are supported by Microchip’s
ProChip Designer and WinCUPL software tools as well
as Precision Synthesis from Mentor Graphic as
described in the “Programmable Logic Device Design
Software Overview”.
To facilitate ISP programming by the Automated Test
Equipment (ATE) vendors, Serial Vector Format (SVF)
files can be created by Microchip provided software
utilities.
Power-Up Reset
ATF1504ASV(L) devices can also be programmed
using standard third-party programmers. With
a
The ATF1504ASV/ATF1504ASVL is designed with a
power-up Reset, a feature critical for state machine ini-
tialization. At a point delayed slightly from VCC crossing
VRST, all registers will be initialized, and the state of
each output will depend on the polarity of its buffer.
However, due to the asynchronous nature of Reset and
uncertainty of how VCC actually rises in the system, the
following conditions are required:
third-party programmer, the JTAG ISP port can be dis-
abled, thereby allowing four additional I/O pins to be
used for logic.
Refer to Programming of PLDs application note for
more details.
ISP Programming Protection
• The VCC rise must be monotonic
The ATF1504ASV(L) has a special feature that locks
the device and prevents the inputs and I/O from driving
if the programming process is interrupted for any rea-
son. The inputs and I/O default to high Z state during
such a condition. In addition, the pin-keeper option pre-
serves the former state during device programming, if
this circuit was previously programmed on the device.
This prevents disturbing the operation of other circuits
in the system while the ATF1504ASV(L) is being pro-
grammed via ISP.
• After Reset occurs, all input and feedback setup
times must be met before driving the clock pin
high
• The clock must remain stable during Power-up
Reset
The ATF1504ASV/ATF1504ASVL has two options for
the hysteresis about the Reset level, VRST, Small and
Large. To ensure a robust operating environment in
applications where the device is operated near 3.0V, it
is recommended that during the fitting process users
configure the device with the Power-up Reset hystere-
sis set to Large. Users of the POF2JED conversion util-
ity should include the flag “-power_reset” on the
command line after “filename.POF”. To allow the regis-
ters to be properly reinitialized with the Large hystere-
sis option selected, the following condition is added:
All ATF1504ASV(L) devices are initially shipped in the
erased state, thereby making them ready to use for ISP.
• If VCC falls below 2.0V, it must shut off completely
before the device is turned on again
2019 Microchip Technology Inc.
DS20006185A-page 7
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