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TMC4670 Datasheet PRELIMINARY • IC Version V0.99 | Document Revision V0.91 • 2016-Nov-09
3.3.2 Register Access Datagram Examples
0x0100000000h : reads data from address 0x01h
0x8123456789h : writes data 0x23456789h to address 0x01h
3.3.3 Identification of Silicon via Type, Version, Date, and Time
The read-only registers of silicon type, version with date and time identify the type of the silicon, the version
of the silicon together with unique date stamp and time stamp. This enables the automatic identification
of IC and version and enable the automatic handling of different IC and different versions.
3.3.4 Read of RAW Inputs & RAW Outputs
For ease-of-use while setting up the configuration, raw input signals and raw output signals are mapped
into the register bank for user read out. With this, the user can initially check without a scope that the
desired signals come into the TMC4670 as expected. Examples of readable raw input signals are digital
Hall signals and incremental encoder signals.
3.4 Numerical Representation, Electrical Angle, Mechanical Angle, and Pole Pairs
The TMC4670 uses different numerical representations for different parameters, measured values, and
interim results. The terms electrical angle PHI_E, mechanical angle PHI_M, and number of pole pairs
(N_POLE_PAIRS) of the motor are important for setup of FOC. This section describes the different numerical
representations of parameters and terms.
3.4.1 Numerical Representation
The TMC4670 uses singed and unsigned values of different length and fixed point representation for
parameters that require a non-integer granularity.
Symbol Description
Min
Max
65535
u16 unsigned 16 bit value
0
-32767
0
s16 signed 16 bit values, 2’th complement
u32 unsigned 32 bit value
32767
232 = 4294967296
s32 signed 32 bit values, 2’th complement
-2147483647 231 - 1 = 2147483647
q8.8 signed fix point value with 8 bit interger part
-32767/256
32767/256
and 8 bit fractional part
q4.12 signed fix point value with 4 bit interger part -32767/4096
-32767/4096
and 12 bit fractional part
Table 3: Numerical Representations
Two’s complement of n bit is
−
2n−1 . . .
−
2n−11
−
1. To avoid un-wanted overflow,
Info
the range is clipped to −2n−1 + 1 . . . −2n−11 − 1.
Because the zero is interpreted as a positive number for 2’th complement representation of interger n bit
number, the smallest negative number is 1. Using
2(n−1) where the largest positive number is 2(n−1)
−
−
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