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(a) Unit test mode
When a high-level signal is being input to the BUNRI and TEST pins, the input from the TBI39 to TBI0 pins
is enabled in their place. Also, the test result is output from the TBO34 to TBO0 pins.
Input/output signals from the following pins are also valid in test mode, and operate in the same way as in
normal mode. Accordingly, in test mode, be sure to handle these pins as indicated in 9.4 Handling of
Each Pin in Test Mode.
• VSB pins
• NPB pins
• VFB pins
• VDB pins
• Instruction cache pins
• Data cache pins
• RCU pins
Caution Unit test mode is the mode used by NEC to perform testing. Test patterns are provided
by NEC.
(b) Standby test mode
When a high-level signal is being input to the BUNRI pin and a low-level signal is being input to the TEST
pin, the NU85E is in standby test mode.
The input to the TBI39 to TBI0 pins is ignored, and the TBO34 to TBO0 pins are set to high impedance.
9.1.3 BUNRIOUT pin
The level input to the BUNRI pin is output as is from the BUNRIOUT pin. To support the test bus automatic
connection tool, use the output from the BUNRIOUT pin and not that from the BUNRI pin if BUNRI signal logic is
required for user circuit separation during the core testing or in places that are not targets of test bus automatic
connection such as the cache.
9.2 List of Test Interface Signals
Signal Name
I/O
PHTDIN1,
Output
PHTDIN0
PHTDO1, PHTDO0
Input
TESEN
Output
VPTCLK
Output
PHTEST
Output
TMODE1
Output
TMODE0
Output
TBREDZ
Output
Caution The above signals are only required for tests performed at NEC.
CHAPTER 9 TEST FUNCTION
Dedicated test signals output to peripheral macros
Dedicated test signals input from peripheral macros
Enable signal output for setting peripheral macros to test mode
Peripheral macro test clock output
Status signal output pin indicating peripheral test mode status
Test mode selection output
These are NEC reserved pins. Leave them open.
Preliminary User's Manual A14874EJ3V0UM
Function
231
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