Testability
314 Datasheet
The above figure shows the wave forms to be able to boot the part into XOR mode. The
straps that need to be controlled during this boot process are BSEL[2:0], RSVD (Ball
L18), EXP_SLR, and XORTEST.
On the X38 Express Chipset platforms, all strap values must be driven before PWROK
asserts. BSEL0 must be a 1. BSEL[2:1] need to be defined values, but logic value in
any order will do. XORTEST must be driven to 0.
Not all of the pins will be used in all implementations. Due to the need to minimize test
points and unnecessary routing, the XOR Chain 14 is dynamic depending on the values
of EXP_SLR, and RSVD (Ball L18). See Figure 30 for what parts of XOR Chain 14
become valid XOR inputs depending on the use of EXP_SLR and RSVD (Ball L18).
13.2 XOR Chain Definition
The MCH has 15 XOR chains. The XOR chain outputs are driven out on the following
output pins. During fullwidth testing, XOR chain outputs will be visible on both pins.
Table 30. XOR Chain 14 Functionality
RSVD (Ball L18) EXP_SLR XOR Chain 14
10
EXP_RXP[15:0]
EXP_RXN[15:0]
EXP_TXP[15:0]
EXP_TXN[15:0]
11
EXP_RXP[15:0]
EXP_RXN[15:0]
EXP_TXP[15:0]
EXP_TXN[15:0]
00
EXP_RXP[15:8]
EXP_RXN[15:8]
EXP_TXP[15:8]
EXP_TXN[15:8]
01
EXP_RXP[7:0]
EXP_RXN[7:0]
EXP_TXP[7:0]
EXP_TXN[7:0]
10
EXP_RXP[15:0]
EXP_RXN[15:0]
EXP_TXP[15:0]
EXP_TXN[15:0]
11
EXP_RXP[15:0]
EXP_RXN[15:0]
EXP_TXP[15:0]
EXP_TXN[15:0]
