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Extended Temperature 82439TX (MTXC) Datasheet
97
PRELIMINARY
10.0. TESTABILITY
10.1.
NAND Tree Mode
A NAND tree mode is provided for Automated Test Equipment (ATE) board level testing. The NAND tree
allows the tester to set the connectivity of each of the MTXC’s signal pins. In Mobile/desktop mode, the
NAND tree mode is activated by driving the test pin TEST# low when REQx# pins are at 0010. If TEST# is
negated at any time, the test mode is deactivated and the MTXC goes back to normal operation. There is no
guarantee that upon re-entering normal operation the chip will function properly, if the test mode was entered
while the MTXC was not in a completely idle state.
The MTXC has several test modes to improve board manufacturing. If the TEST# signal is asserted (driven
low), the value on the REQ[3:0]# indicates the test mode to enable. The test mode enabled at the falling edge
of TEST# will remain enabled until TEST# is negated.
Table 26 shows each test mode and the value of REQ#[3:0] required to enable it. All other values of
REQ[3:0]# while TEST# is active, are reserved and should not be asserted by the customer.
Table 26. Test Modes
REQ[3:0]#
TEST#
PHLD#
TEST Mode
Description
0010
0
x
NAND Chain
Float outputs, enable NAND chains on GNT[3:0]#
1110
0
1
ID/REV code
Drives Device ID on AD[31:16] and revision ID on
AD[7:0]
1110
0
0
MID Code
Drives Manufacture ID on AD[31:0]
1111
0
x
Disable test
mode
1
Disables any active test mode, puts MTXC back into
normal mode
NOTES:
1.
It is recommended to assert RST# if this mode is used, to guarantee pins and PCIset will function
normally.
10.2.
NAND Chain Mode
In NAND Tree mode, all outputs are tri-stated, except for GNT#[3:0]. These pins contain the NAND Chain.
Note, also, that the internal pull-ups and pull-downs are still active. Because of the 282 pins in the NAND
Chain, it must be separated into 4 chains. Two chains contain 72 pins each, 1 chain contains 70 pins, and 1
chain contains 68 pins. The MTXC remains in this mode until a new test mode is selected or RST# is
asserted. The HCLK and PCLK are part of the NAND Chain and
must
be deactivated during this test.