Analog Devices EE195 Application Notes

Engineer To Engineer Note EE-195

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Technical Notes on using Analog Devices' DSP components and development tools

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Moving from the ADSP-21160M SHARC® DSP to the ADSP-21160N
SHARC DSP

Contributed by G. Linden September 2, 2003

Introduction

While functionally the ADSP-21160M SHARC®
DSP and ADSP-21160N SHARC DSP are
essentially the same, there are some issues that
need to be addressed when moving from ADSP­21160M to the ADSP-21160N in your design. It
is important to look at the datasheet for the
ADSP-21160N when migrating your design to
the ADSP-21160N. Below is a list of items to
keep in mind:

list are available on the web at
www.analog.com

5. Since the ADSP-21160N does not have many

of the anomalies that are present on the
ADSP-21160M silicon, those M specific
workarounds should not be implemented in
the N design. We recommend that any
workarounds implemented be reviewed for
compatibility to N silicon. Below are some
notes on anomaly workarounds that should
be reversed when moving to N silicon:

Considerations

1. The nominal core voltage requirement on the

ADSP-21160N is 1.9V vs. the 2.5V required
on the ADSP-21160M.

2. On the ADSP-21160N, an external pull-up

resister should be placed on /HBG as some
aspects of the host bus signaling were
changed in the silicon for the ADSP-21160N.
We recommend a resistor value in the 20­50K ohm range be placed on /HBG.

3. The new startup specification will apply to

ADSP-21160N due to the PLL re-design.
This information is documented in the
ADSP-21160N datasheet.

4. All anomalies on the ADSP-21160M have

been resolved in the ADSP-21160N except
for anomalies numbers 44-56 and anomaly
number 14. Both the ADSP-21160N
anomaly list and the ADSP-21160M anomaly

a. Anomaly #13 IMASKP register not

updated correctly - If the workaround is
left unchanged in design when moving to
N silicon the workaround will result in
incorrect interpretation of IMASKP
settings. Backing out workaround can be
done via the use of conditional code
based upon silicon ID information in
MODE2_SHDW register and thus
accommodate all revisions of ADSP­21160M and ADSP-21160N.

b. Anomaly #44 IMASKP bits are left

shifted by 1 bit for writes to bits 14-31.
If the workaround is left in place it will
result in incorrect settings of IMASKP
register by user code. Backing out
workaround can be done via the use of
conditional code based upon silicon ID
information in MODE2_SHDW register
and thus accommodate all revisions of
ADSP-21160M and ADSP-21160N.

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c. Anomalies #22 and #23 deal with the

PLL and power sequencing. Do not
implement the workaround in the ADSP­21160M anomaly list. Instead be sure to
follow the power up sequence
documented in the ADSP-21160N
datasheet.

Check the ADSP-21160N anomaly list for
anomalies that would be present on the
ADSP-21160N and not on the ADSP­21160M. There are anomaly workarounds
that do not need to be reversed, but can be
reversed to simplify your system or increase
available bandwidth.

6. A number of pins on the ADSP-21160N ball

out are different than the ones on the ADSP­21160M ball out. To be exact, A14, B13,
C12 are connected to VDD and M4 is
connected to GND on the ADSP-21160M
silicon, but are NC on the ADSP-21160N
silicon. Those pins are not connected
internally. While you can just as well leave
them floating, connecting them to GND or
Voltage won't do any harm. You will not
need to implement layout changes due to the
fact that this pins are indicated as NC in the
datasheet.

References

[1] ADSP-21160M SHARC DSP Datasheet. Rev. 0, Analog Devices, Inc.

[2] ADSP-21160N SHARC DSP Datasheet. Rev PrB, Analog Devices, Inc.

[3] ADSP-21160M anomaly list. April 2003, Analog Devices, Inc.

[4] ADSP-21160N anomaly list. April 2003, Analog Devices, Inc.

[5] ADSP-21160 Hardware Reference. Second Edition, March 2002. Analog Devices, Inc.

All references are available on the Analog Devices website at www.analog.com

Document History

Version Description

September 02, 2003 by G.Linden Added consideration 6 regarding NC pins on the 21160N

May 21, 2003 by G.Linden Updated item 4 to reflect new anomalies found on the 21160.

June 26, 2002 by G.Linden. Initial Release

Moving from the ADSP-21160M SHARC® DSP to the ADSP-21160N SHARC DSP (EE-195) Page 2 of 2