IC-TW28 Datasheet, PDF (40/80 Pages) IC-Haus GmbH – 10-BIT SIN/COS INTERPOLATOR

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Rev D2, Page 40/80
LED_START
LED_START is a static register containing the initial
(starting) value for the duty cycle of the LED PWM out-
put.
Value
0...255
LED_START (0x0002)
Description
Starting LED PWM duty cycle
Table 42: Starting LED PWM Duty Cycle
TEST
TEST is a static register used to unlock the internal
EEPROM and enable Z test mode. The TEST register
value is not stored in EEPROM and is set to 0 at every
startup.
Value
0
1
TEST.we (0x000B Bit 0)
Description
EEPROM locked (write protection enabled)
EEPROM unlocked (write prot. disabled)
If LED_CFG.en = 1, LED_START is loaded from the
internal EEPROM at startup and used as the initial
value for the LED PWM output. If LED_CFG.en = 1
and LED_CFG.auto = 0, the LED output stays at this
value. If LED_CFG.en = 1 and LED_CFG.auto = 1, the
LED output is adjusted by the LED intensity control
to maintain optimum illumination of an optical sin/cos
sensor.
Table 44: EEPROM Unlock
The EEPROM must be unlocked (TEST.we = 1) to write
to it using COMMAND register commands. The EEP-
ROM can be written at the rising edge of the xCALIB
input regardless of the value of TEST.we. See Hard-
ware Auto Calibration (xCALIB) on page 27 for more
information.
If LED_CFG.en = 0, LED_START has no effect. See
LED Intensity Control on page 72 for more information.
The LED_START value is also used during calibration
(xCALIB input low or command 0x21 – 0x23 active)
regardless of the settings of the LED_CFG register bits.
Value
0
1
TEST.z (0x000B Bit 2)
Description
Normal operating mode
Z test mode
Table 45: Zero Test Mode
LED_PWM
LED_PWM is a dynamic register containing the actual
current operating duty cycle of the LED PWM output.
Value
0...255
LED_PWM (0x0010)
Description
Actual LED PWM duty cycle
In Z test mode, the A outputs show the un-gated Z
signal once per input period, the B outputs show the
internal Z gating signal derived from the ZERO inputs,
and the Z outputs show the gated Z output pulse. Z
test mode is only available if OUTPUT.abzen = 1. See
Z Test Mode and Calibration on page 65 for more infor-
mation.
Table 43: Actual LED PWM Duty Cycle
If LED_CFG.en = 1, LED_PWM is loaded from
LED_START at startup. If LED_CFG.en = 1 and
LED_CFG.auto = 0, the LED_PWM stays equal to
LED_START and the LED output stays at this value. If
a new value is written to LED_PWM, the LED output is
immediately set to this level.
If LED_CFG.en = 1 and LED_CFG.auto = 1, LED_PWM
(and thus the LED output) is adjusted by the LED in-
tensity control to maintain optimum illumination of an
optical sin/cos sensor. If LED_CFG.en = 0, LED_PWM
has no effect. See LED Intensity Control on page 72
for more information.