Freescale Semiconductor Tower System Prototyping Module TWR-PROTO TWR-PROTO Information Guide
Product codes
TWR-PROTO
TWR-PROTO Module Errata
Issue:
The following issue has been discovered with the secondary PCI edge connector on the
TWR-PROTO Rev. A boards. The Power Sense signal on the secondary side of the edge
connector is tied directly to the 3.3V signals on both the primary and secondary edge
connectors. The Power Sense Signal is located on Pin B4 on both the Primary and
Secondary edge connectors.
The Power Sense signal is also connected to B4 and D4 on the TWR-PROTO Primary
and Secondary Connector Signal Access areas. The D4 (Secondary Connector Signal
Access) is connected directly to the 3.3V signals.
Impact:
This issue has the potential of connecting the 5V Power Sense signal to the 3.3V power
supply if the TWR-PROTO module’s secondary edge connector is inserted into a
functional TWR-ELEV.
The following cases will cause the issue to manifest and should be avoided:
1)
The TWR-PROTO module will inserted backwards into a basic Tower system,
consisting of at minimum a TWR-PROTO and TWR-ELEV’s (Functional and
Dummy). In this scenario “backwards” is defined at the TWR-PROTO module’s
secondary edge connector being inserted into the functional elevator and the
primary edge connector being inserted into the dummy elevator.
Dummy). In this scenario “backwards” is defined at the TWR-PROTO module’s
secondary edge connector being inserted into the functional elevator and the
primary edge connector being inserted into the dummy elevator.
2)
The TWR-PROTO module is used with two function elevators. To fully utilize
all functions of certain MCU and MPU Tower module two functional elevators
can be used to expand the secondary backplane to all Tower modules in the
Tower System. The TWR-PROTO Rev A. board should not be used in a Tower
System with dual functional elevators.
can be used to expand the secondary backplane to all Tower modules in the
Tower System. The TWR-PROTO Rev A. board should not be used in a Tower
System with dual functional elevators.
Solution:
The Power Sense signal on the secondary edge connector should be cut. This will isolate
the 3.3V rail from the 5V Power Sense signal. Note that D4 in the Secondary Connector
Signal Access will no longer be connected to the Power Sense signal and should be
considered a 3.3V signal.