IC-TW28 Datasheet, PDF (26/80 Pages) IC-Haus GmbH – 10-BIT SIN/COS INTERPOLATOR

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Rev D2, Page 26/80
Auto Z calibration determines whether the zero chan-
nel is automatically calibrated along with the sin and
cos channels when the xCALIB input is activated. It is
recommended to use auto Z calibration in all applica-
tions using the ZERO inputs. In applications where the
ZERO inputs are not used, select no auto Z calibration.
For example, to configure an interpolation factor of 80,
normal input mode, and auto Z calibration, set C0 to
configuration level 6 and C3 to configuration level 9.
Values for iC-TW28 registers in pin configuration mode
are shown in Table 12 and 13.
Register.bit(s)
MAIN_CFG.input
MAIN_CFG.filter
MAIN_CFG.rs422
MAIN_CFG.irqpp
MAIN_CFG. elinkoff
LED_CFG
UVW_CFG
INTER
INTER1.div
AB.hyst
UVW.hyst
FALARM
ABLIMIT
ZERO0.threshold
ZERO0.mode
ZERO0.clr
ZERO1.zwidth
OUTPUT.apol
OUTPUT.bpol
OUTPUT.zpol
OUTPUT.abzdir
OUTPUT.uvwpol
OUTPUT.uvwdir
OUTPUT.abzen
OUTPUT.uvwen
ZPHASE
UVWPH
FILT_CFG.auto
FILT_CFG.fb
FILT_CFG.kpmax
FILT_LAG. threshold
FILT_K.kp
FILT_K.ki
STAT_CFG.filter
STAT_CFG
STAT_CFG.enc
STAT_CFG.enz
STAT_SEL
STAT_IE.oflow
STAT_IE.falarm
STAT_IE.laglim
STAT_IE.inclim
STAT_IE.lagfatl
STAT_IE.scamp
STAT_IE.adapt
STAT_IE.res
STAT_HIZ
Val. Description
Determined by C3
0 500 kHz max. input freq.
1 RS422 ABZ outputs
0 Open-drain xIRQ output
0 Encoder Link available
0 LED PWM disabled
0 UVW disabled
Determined by C0/C3
0 No post-AB divider
Determined by C1
0 0^◦ UVW hysteresis
0 No input freq.alarm
Determined by C2
10 42% of signal amplitude
0 Position capture on Z
0 Never clear mcc
0 1AB edge (quad. state)
0 Normal polarity
0 Normal polarity
0 Z is active high
0 Normal AB direction
0 Normal UVW polarity
0 Normal UVW rotation
1 ABZ outputs
0 No UVW outputs
0 Affected by C3
0 No UVW phase shift
0 Static kp
0 No feedback delay
6 Max. dynamic kp limit
12 Filter lag threshold
Determined by C1
3 Maximum ki
3 2.5 ms status filter
1 IRQ extended by 40 ms
0 No IRQ on mcc oflow
0 No IRQ on pos. capture
0 STAT_VAL for IRQ
0 No IRQ on overflow
0 No IRQ on FALARM
0 No IRQ on excess lag
1 IRQ on AB/UVW limit
1 IRQ on fatal lag
1 IRQ on amplitude lo/hi
0 No IRQ on excess adapt
0 No IRQ on residuals
0 Outputs always enabled
Table 12: Pin Configuration Mode Register Values
START.wait
START.mode
START.nostart
ADAPT_CFG0
ADAPT_CFG1.p
ADAPT_CFG1.stop
ADAPT_CFG1. zcal
ADAPT_CFG1.xcalee
SC_AMP_TARG
SC_AMP_LOW
SC_AMP_HIGH
S_OFS_BASE
C_OFS_BASE
SC_OFS_LIM
SC_OFS_TH
SC_BAL_BASE
SC_BAL_LIM
SC_BAL_TH
SC_PH_BASE
SC_PH_LIM
SC_PH_TH
Z_PH_TH
Z_GNA_COR
3 10 ms startup wait time
1 Same phase startup
0 Automatic startup
Determined by C2
1 Slow auto adaption rate
1 Stop auto adaption on
SCAMP
Determined by C3
1 Store to EEPROM when
xCALIB de-activates
150 Sin/cos amplitude target
90 –40% SC_AMP_TARG
180 +20% SC_AMP_TARG
0 Not used
0 Not used
127 Not used
0 Not used
0 Not used
127 Not used
0 Not used
0 Not used
127 Not used
0 Not used
0 Not used
8 Affected by C3
Table 13: Pin Configuration Mode Register Values
(continued)
Serial Configuration Mode
In serial configuration mode (PINCFG = 0 V), configu-
ration values for all static registers must be written to
the TW28’s internal EEPROM using the SPI port or
the Encoder Link interface before the device can be
used. For stand-alone applications, the easiest way to
accomplish this is to use the iC-TW28 demo board and
the free Graphical User Interface (GUI) software.
The iC-TW28 TW28_1D evaluation board implements
the iC-TW28 and a USB interface for direct communi-
cation with the GUI software running on a Windows PC.
A functional prototype encoder can thus be quickly as-
sembled and configured. See the TW28_1D evaluation
board documentation for more information.
The TW28_1D evaluation board can also be used
for prototype development to configure an external
iC-TW28 via the SPI or Encoder Link interfaces using
the free GUI software. In series production, the eval-
uation board can be employed to download pre-engi-
neered configurations to iC-TW28s embedded in prod-
ucts.
In hosted applications (where the SPI port is used
to communicate with the host processor or microcon-
troller), the iC-TW28 must be configured via the host
or using the Encoder Link interface. Communication
protocols for the SPI port and Encoder Link interface as
well as internal registers are explained in subsequent
sections of this document.