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1. ALE signal is not connected to the bus in PCB revision G and earlier.
ISSUE 1 : ALE Signal is not connected to the bus
Symptom:
Some peripheral devices do not function properly on the I/O bus, typically failing during bus
enumeration.
Root Cause:
The ALE signal is not connected to Pin B28 of the PC/104 connector. ALE by definition states
that when high, addresses SA[23:17] are valid and can be latched. Since I/O addresses are
limited to 16 bits (SA[15:0]), most PC/104 peripherals do not require this signal. However,
peripherals that utilize a multiplexed address and data bus, like the SJA1000, use ALE to switch
between address and data.
Resolution:
A validated hardware rework and firmware change is available to connect the ALE pin to the
controller. Please contact an Application Engineer for details on Revision G PCB products. The ALE
signal is corrected in revision H and later PCBs and requires no modification.