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3 command sequence for setting clock divide value, 4 changes to the period select value, Command sequence for setting clock divide value – PNI RM3000-F Sensor Suite User Manual

Page 41: Changes to the period select value, Table 6-4: enhanced legacy mode with cd = 1

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PNI Sensor Corporation

Doc #1016102 r04

RM3000-f & RM2000-f Sensor Suite User Manual

Page 41

6.2.3 Command Sequence for Setting Clock Divide Value

A sample command sequence is given below which sets the Clock Divide Value to “1”.

Set SSN to LOW.

Send 0x80 (this is the Command Byte to write to the Clock Divide Register)

Send 0 (this sets the Clock Divide Value to “1”)

Set SSN to HIGH

6.2.4 Changes to the Period Select Value

Since the high-speed clock is running faster, the time resolution of the measurement is

increased. Consequently, the number of cycle counts required to achieve a desired

magnetic field sensitivity is substantially reduced, and the Period Select value in the

Legacy Command Byte should be altered. Generally speaking, the best performance will

be obtained with the Clock Divide Value set to 1.

Table 6-4: Enhanced Legacy Mode with CD = 1

Default Legacy

Enhanced Legacy with CD = 1

Period

Select

Cycle

Counts

Equivalent

1

Period Select

Cycle

Counts

Power

Consumption

Gain

0

32

0

32

same

16x greater

1

64

0

32

~40% reduction

8x greater

2

128

0

32

~65% reduction

4x greater

3

256

0

32

~80% reduction

2x greater

4

512

1

64

~90% reduction

Same

5

1024

2

128

~90% reduction

Same

6

2048

3

256

~90% reduction

Same

7

4096

4

512

~90% reduction

Same

Footnote:

1. Equivalent Period Select is defined as the Period Select Value that provides equivalent gain to
the default Legacy Mode. If the Equivalent Period Select Value cannot be reduced (i.e. is at 0),
then the improvement in Gain is shown.