Command byte – PNI MS2100 User Manual
Page 10
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DOC # 1011946 R07
21-Jan-11
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MS2100
Specifications & Instructions
Command Byte
The operation of the MS2100 is controlled by the data received into the SPI port. The command byte
syntax is as follows:
Table 7: Command Byte Syntax
Position
7
6
5
4
3
2
1
0
Bit
DHST
PS2
PS1
PS0
ODIR
MOT
ASI
ASO
RESET
0
0
0
0
0
0
0
0
DHST – High Speed Oscillator Test
When high, the internal high speed clock is set to drive the DHST pad at ½ the clock speed.
When low, the DHST pad is set to DVDD. This is used for debug purposes only, and will not be
set in normal operation.
PS0, PS1, and PS2 – Period Select
Selects the division ratio applied to the L/R oscillator output to set the period being measured.
Table 8: Period Select Division Ration
PS2
PS1
PS0
Ratio
0
0
0
/32
0
0
1
/64
0
1
0
/128
0
1
1
/256
1
0
0
/512
1
0
1
/1024
1
1
0
/2048
1
1
1
/4096
ODIR – Oscillator Direction
Determines the magnetic oscillator direction if MOT is set to 1. It has no effect on direction when
the MOT bit is set to zero. This is used for debug purposes only, and will not be set in normal
operation.
MOT – Magnetic Oscillator Test
When set, causes the magnetic oscillator selected by AS0 and AS1 in the directions
selected by ODIR to run continuously until MS2100 is reset.