ADSP-2185 Anomaly List for Revision 0.0 PDF

a
12/15/98
Computer Products Division
ADSP-2185 Anomaly List for Revision 0.0
The list below represents the known anomalies and workarounds for the ADSP-2185. The silicon revision
of a particular device can be found on the chip, as shown below:
ADSP-2185
-xxx
xyzzzzzzz-0.0
Dwwyy
Part Number
Speed Grade/Package
Lot number and silicon revision
Date code
The table below shows which ADSP-2185s have each anomaly. The left hand side of the table lists the
type of anomaly and the numbers on the top of the table refer to the particular revision of the silicon. Any
box that has an ‘x’ contained in it has that anomaly. For a complete description of the anomaly, please
refer to the subsequent pages.
1.
BDMA Write Glitch
a
0.0
x
55-101396-00
Page 1 of 2
a
12/15/98
Computer Products Division
Anomaly #1
During a wait-stated Byte DMA write cycle, the DSP will drive data lines D15-D8 (all other data lines are
not affected) low for approximately 2ns every processor cycle regardless of the number of BDMA software
wait states. This will create a glitch on data lines D15-D8 just prior to the correct data being latched on
the bus. The size of the glitch depends on the loading of the data bus. This anomaly effectively changes
the formula for the “Data setup before WR~ High” (tDW) timing specification. The formula changes from:
.5tck-7+w ns
.5tck-7 ns
to
This anomaly only affects data lines D15-D8 when performing wait stated BDMA writes. The address bus
and write strobe work properly with any wait state value.
Workaround:
A latch could be used to capture the information on the BDMA data lines during the period that the
information being written is stable. Also, because of the brevity of the glitch, the capacitance on the data
bus may be enough to hold the data values to a sufficient level.
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55-101396-00
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