
Engineer To Engineer Note  EE-195 
a 
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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a 
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