
Test Operation
8-2
ColdFire2/2M User’s Manual
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MOTOROLA
8.1.4 Scan Mode (SCAN_MODE).
This active-high, unidirection input signal gates off all memory array outputs during scan
testing.SCAN_MODE must be asserted for the duration of scan testing.
8.1.5 Scan Output (SO[15:0])
These output signals are connected to the 16 internal ColdFire2/2M scan chain outputs.
8.1.6 I/O Test Ring Clock (TRCLK)
This input signal is the synchronous clock used to transition the test ring during scan testing.
TR_CLK is connected to the clock input of all I/O test ring registers.
8.1.7 I/O Test Ring Core Mode Enable (CORE_TEST)
This active-high input signal enables the core mode of the test ring during scan testing. The
test ring is in scan core mode if CORE_TEST is asserted and in scan ASIC mode if
CORE_TEST is negated.
8.1.8 I/O Test Ring Data Input (TR_SDI[1:0])
These input signals are the serial data inputs for the I/O test ring chains.
8.1.9 I/O Test Ring Data Output (TR_SDO[1:0])
These output signals are the serial output data from the I/O test ring chains.
8.1.10 I/O Test Ring Enable (TR_SE)
This active-high input signal enables the test ring. TR_SE is connected to the scan enable
input of all I/O test ring scannable registers.
8.1.11 I/O Test Ring Mode (TR_MODE)
This active-high input signal enables the scan test mode of the test ring. The test ring is in
scan test mode if TR_MODE is asserted and in normal functional mode if negated.
TR_MODE should be asserted for the duration of scan testing, and be held negated for the
duration of memory testing and during functional operation of the device.
8.1.12 TEST WRITE INHIBIT (TEST_WR_INH).
Optional: Asserting this signal will prevent strobing; i.e. writing, of any of the integrated
memories. However, as long as SCAN_MODE is asserted, the array outputs are gated off
from the ColdFire2/2M and will not affect the scan vectors.
8.2 SCAN OPERATION
Motorola provides ATPG vectors for the ColdFire2/2M. The signals listed in the previous
section must be brought out to package pins (muxed out) in order for Motorola supplied scan
vectors to be applied. This section provides an understanding of the ColdFire2/2M scan
implementation. The following diagram illustrates the ColdFire2/2M scan test
implementation:
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