Specifications

12 158004.B00
1.7 AVOIDING COMMON PROBLEMS
This section draws your attention to a number of issues that can cause problems, but
that can be avoided if you are aware of them.
The battery pin must not be connected to +5V and must not be left floating. See
section 3.6 for further details.
Some old disk drives and some Compact Flash cards do not report their parameters
and so the parameters will need to be set manually for these devices. See section 3.9
for further details.
Some form of cooling may be needed for the Geode GX1 processor. This is
discussed in section 2.1.
The VGA display controller and SoundBlaster-compatible audio circuitry is not fully
implemented within the Geode chip. Missing registers are emulated in software, using
SMIs (System Management Interrupts). This can cause problems in certain cases,
although there is usually a work-around. When the VGA emulation is in operation, in
some display modes, a regular SMI occurs every 1ms. During this time the Geode will
not respond to interrupts, and if interrupts are arriving at high speed (due to high-
speed serial comms for example) then interrupts can be lost. There are solutions for
Windows, Linux and some other operating systems, and work-arounds to some
extent for DOS. The problem and its resolution are discussed in section 3.10.5.
If you find that a USB peripheral does not operate correctly when directly plugged into
the TP400, then you should consider using a powered hub. This is discussed in
section 3.14.