XA2C256-7TQG10I XILINX [Xilinx, Inc], XA2C256-7TQG10I Datasheet - Page 18

• Manufacturer Part Number: XA2C256-7TQG10I
• Description: CoolRunner-II Automotive CPLD
• Manufacturer: XILINX [Xilinx, Inc]

XA2C256 CoolRunner-II Automotive CPLD
5. Avoid pull-down resistors. Always use external pull-up
6. Do not drive I/Os pins above the V
7. Do not rely on the I/O states before the CPLD
8. Use a voltage regulator which can provide sufficient
9. Ensure external JTAG terminations for TMS, TCK, TDI,
10. Attach all CPLD V
11. Decouple all V
12. Configure I/Os properly. CoolRunner-II Automotive
Recommendations
The following recommendations are for all automotive appli-
cations.
Automotive Warranty Disclaimer
THIS WARRANTY DOES NOT EXTEND TO ANY IMPLEMENTATION IN AN APPLICATION OR ENVIRONMENT THAT IS
NOT CONTAINED WITHIN XILINX SPECIFICATIONS. PRODUCTS ARE NOT DESIGNED TO BE FAIL-SAFE AND ARE
NOT WARRANTED FOR USE IN THE DEPLOYMENT OF AIRBAGS. FURTHER, PRODUCTS ARE NOT WARRANTED
FOR USE IN APPLICATIONS THAT AFFECT CONTROL OF THE VEHICLE UNLESS THERE IS A FAIL-SAFE OR
REDUNDANCY FEATURE AND ALSO A WARNING SIGNAL TO THE OPERATOR OF THE VEHICLE UPON FAILURE.
USE OF PRODUCTS IN SUCH APPLICATIONS IS FULLY AT THE RISK OF CUSTOMER SUBJECT TO APPLICABLE
LAWS AND REGULATIONS GOVERNING LIMITATIONS ON PRODUCT LIABILITY.
18
resistors if external termination is required. This is
because the CoolRunner-II Automotive CPLD, which
includes some I/O driving circuits beyond the input and
output buffers, may have contention with external
pull-down resistors, and, consequently, the I/O will not
switch as expected.
I/O bank.
a. The current flow can go into V
b. It can also increase undesired leakage current
c. If done for too long, it can reduce the life of the
configures. During power up, the CPLD I/Os may be
affected by internal or external signals.
current during device power up. As a rule of thumb, the
regulator needs to provide at least three times the peak
current while powering up a CPLD in order to guarantee
the CPLD can configure successfully.
TDO should comply with the IEEE 1149.1. All Xilinx
CPLDs have internal weak pull-ups on TDI, TMS, and
TCK.
necessary power and ground supplies around the
CPLD.
0.01 μF and 0.1 μF closest to the pins for each
V
CPLDs have I/O banks; therefore, signals must be
assigned to appropriate banks (LVCMOS33,
LVCMOS18 …)
CC
voltage regulator.
associated with the device.
device.
/V
CCIO
-GND pair.
CC
and V
CC
and GND pins in order to have
CCIO
pins with capacitors of
CCIO
CCIO
and affect a user
assigned to its
www.xilinx.com
1. Use strict synchronous design (only one clocking event)
2. Include JTAG stakes on the PCB. JTAG stakes can be
3. CoolRunner-II Automotive CPLDs work with any power
4. Do not disregard report file warnings. Software
5. Understand the Timing Report. This report file provides
6. Review Fitter Report equations. Equations can be
7. Let design software define pinouts if possible. Xilinx
8. Perform a post-fit simulation for all speeds to identify
9. Distribute SSOs (Simultaneously Switching Outputs)
10. Terminate high speed outputs to eliminate noise caused
if possible. A synchronous system is more robust than
an asynchronous one.
used to test the part on the PCB. They add benefit in
reprogramming part on the PCB, inspecting chip
internals with INTEST, identifying stuck pins, and
inspecting programming patterns (if not secured).
sequence, but it is preferable to power the V
(internal V
which any glitches from device I/Os are unwanted.
identifies potential problems when compiling, so the
report file is worth inspecting to see exactly how your
design is mapped onto the logic.
a speed summary along with warnings. Read the timing
file (*.tim) carefully. Analyze key signal chains to
determine limits to given clock(s) based on logic
analysis.
shown in ABEL-like format, or can also be displayed in
Verilog or VHDL formats. The Fitter Report also
includes switch settings that are very informative of
other device behaviors.
CPLD software works best when it selects the I/O pins
and manages resources for users. It can spread signals
around and improve pin-locking. If users must define
pins, plan resources in advance.
any possible problems (such as race conditions) that
might occur when fast-speed silicon is used instead of
slow-speed silicon.
evenly around the CPLD to reduce switching noise.
by very fast rising/falling edges.
CC
) before the V
CCIO
DS555 (v1.1) May 5, 2007
for the applications in
Product Specification
CCI
R