EP3C16F256I7 Altera, EP3C16F256I7 Datasheet - Page 395

• Manufacturer Part Number: EP3C16F256I7
• Description: Cyclone III
• Manufacturer: Altera

BST for
Configured
Devices
Disabling IEEE
Std. 1149.1 BST
Circuitry
Altera Corporation-Preliminary
March 2007
f
For more information on using the IEEE Std.1149.1 circuitry for device
configuration, refer to the Configuring Cyclone III Devices chapter of the
Cyclone III Device Handbook.
For a configured device, the input buffers are turned off by default for
I/O pins that are set as output only in the design file. Nevertheless,
executing the SAMPLE instruction will turn on the input buffers for the
output pins. You can set the Quartus
input buffers on a configured device so it behaves the same as an
unconfigured device for boundary-scan testing, allowing sample
function on output pins in the design. This aspect can cause a slight
increase in standby current because the unused input buffer is always on.
In the Quartus II software, do the following:
1.
2.
3.
4.
The IEEE Std. 1149.1 BST circuitry for Cyclone III devices is enabled upon
device power-up. Because the IEEE Std. 1149.1 BST circuitry is used for
BST or in-circuit reconfiguration, you must enable the circuitry only at
specific times as mentioned in, "Using IEEE Std. 1149.1 BST Circuitry"
1
Table 14–6
Std. 1149.1 circuitry in Cyclone III devices.
Choose Settings (Assignments menu).
Click Assembler.
Turn on Always Enable Input Buffers.
If you use the default setting with input disabled, you need to
convert the default BSDL file to the design-specific BSDL file using
the BSDL Customizer script. For more information regarding BSDL
files, refer to the
Support”
If you are not using the IEEE Std. 1149.1 circuitry in Cyclone III,
then you should permanently disable the circuitry to ensure that
you do not inadvertently enable when it is not required.
shows the pin connections necessary for disabling the IEEE
section on page 21.
“Boundary-Scan Description Language (BSDL)
Cyclone III Device Handbook, Volume 1
®
II software to always enable the
BST for Configured Devices
14–21