Chapter 8: JTAG Boundary-Scan Testing in MAX V Devices
8–15
Disabling IEEE Std. 1149.1 BST Circuitry
Disabling IEEE Std. 1149.1 BST Circuitry
You can enable the IEEE Std. 1149.1 BST circuitry for MAX V devices after device
powers up. You must enable this circuitry only if you use the BST or ISP features. This
section describes how to disable the IEEE Std. 1149.1 circuitry to ensure that the
circuitry is not inadvertently enabled when it is not required.
Table 8–3 lists the pin connections necessary for disabling JTAG in MAX V devices
that have dedicated IEEE Std. 1149.1 pins.
Table 8–3. Disabling IEEE Std. 1149.1 Circuitry for MAX V Devices
JTAG Pins (1)
TMS
VCC (2)
TCK
TDI
TDO
GND (3)
VCC (2)
Leave Open
Notes to Table 8–3:
(1) There is no software option to disable JTAG in MAX V devices. The JTAG pins are dedicated.
(2) VCC refers to VCCIO of Bank 1.
(3) The TCKsignal may also be tied high. If TCKis tied high, power-up conditions must ensure that TMSis pulled high
before TCK. Pulling TCKlow avoids this power-up condition.
Guidelines for IEEE Std. 1149.1 Boundary-Scan Testing
When performing boundary-scan testing with IEEE Std. 1149.1 devices, use the
following guidelines:
■
If a pattern (for example, a 10-bit 1010101010pattern) does not shift out of the
instruction register through the TDOpin during the first clock cycle of the SHIFT
_
IR
state, the proper TAP controller state has not been reached. To solve this problem,
try one of the following procedures:
■
Verify that the TAP controller has reached the SHIFT
_
IRstate correctly. To
advance the TAP controller to the SHIFT_IRstate, return to the RESETstate and
clock the code 01100on the TMSpin.
■
Check the connections to the VCC, GND, and JTAG pins on the device.
■
Perform a SAMPLE/PRELOADtest cycle before the first EXTESTtest cycle to ensure that
known data is present at the device pins when EXTESTmode is entered. If the OEJ
update register contains a 0, the data in the OUTJupdate register will be driven out.
The state must be known and correct to avoid contention with other devices in the
system.
■
Do not perform EXTESTand SAMPLE/PRELOADtests during ISP. These instructions
are supported before and after ISP but not during ISP.
1
If problems persist, contact Technical Support.
Boundary-Scan Description Language Support
The BSDL—a subset of VHDL—provides a syntax that allows you to describe the
features of an IEEE Std. 1149.1 BST-capable device that can be tested. Test software
development systems then use the BSDL files for test generation, analysis, failure
diagnostics, and in-system programming.
December 2010 Altera Corporation
MAX V Device Handbook
ALTERA [ ALTERA CORPORATION ]
