Rainbow Electronics LM93 - Manual (Page 33)

15.0 Using The LM93
(Continued)
15.11 XOR TREE TEST
An XOR tree is provided in the LM93 for Automated Test
Equipment (ATE) board level connectivity testing. This al-
lows the functionality of all digital inputs to be tested in a
simple manner and any pins that are non-functional or shorted together to be identified. When the test mode is
enabled by setting the ‘XEN’ bit in the XOR Test register, the
part enters XOR test mode.
The following signals are included in the XOR test tree:
Px_VIDy GPIO_x PWMx Px_PROCHOT VRDx_HOT SCSI_TERMx RESET
Since the test mode is XOR tree, the order of the signals in
the tree is not important. SMBDAT and SMBCLK should not
be included in the test tree.
Example of XOR Test Tree (not showing all signals)
20068219
To properly implement the XOR TREE test on the PCB, no
pins listed in the tree should be connected directly to power
or ground. If a pin needs to be configured as a permanent
low, such as an address, it should be connected to ground
through a low value resister such as 10 k
Ω, to allow the ATE
(Automatic Test Equipment) to drive it high.
When generating test waveforms, a typical propagation de-
lay of 500 ns through the XOR tree should be allowed for.
LM93
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