MCZ33991EG Freescale, MCZ33991EG Datasheet - Page 26

• Manufacturer Part Number: MCZ33991EG
• Manufacturer: Freescale

Specifications of MCZ33991EG

• Operating Current: 6mA
• Operating Temperature Classification: Automotive
• Package Type: SOIC W
• Operating Supply Voltage (min): 4.5V
• Operating Supply Voltage (typ): 5V
• Operating Supply Voltage (max): 5.5V
• Lead Free Status / RoHS Status: Compliant

continue indefinitely until the RTZR bit D1 is used to stop the
RTZ event.
alignment prior to the RTZ event, may result in a false RTZ
detection. More specifically, an RTZ event beginning from a
non-full step position, may result in an abbreviated
integration, interpreted as a stalled pointer. Similarly, if the
magnetic fields of the energized coils and the rotor are not
aligned prior to initiating the RTZ, the integration results may
mistakenly indicate the pointer has stopped moving.
(CW) to the nearest full step position, e.g., 24, 30, 36,42,48...
prior to initiating an RTZ, ensures the magnetic fields are
aligned. Doing that increases the chances of a successful
pointer stall detection. It is important the pointer be in a static,
or commanded position before starting the RTZ event.
Because the time duration and the number of steps the
pointer moves prior to reaching the commanded position can
vary depending upon its status at the time a position change
is communicated, the master should assure sufficient
elapsed time prior to starting an RTZ. If an RTZ is desired
after first enabling the outputs, or after forcing a reset of the
device, the pointer should first be commanded to move 24
microstep steps CW to the nearest full step location. Because
RTZ OUTPUT
determine the state of the motor. The 33991 multiplexes the
coil voltages and provides the signal from the non-driven coil,
to the RTZ pin.
26
33991
TIMING DESCRIPTIONS AND DIAGRAMS
DEVICE FUNCTIONAL DESCRIPTION
A pointer not on a full step location, or in magnetic
Advancing the pointer by at least 24 microsteps clockwise
During an RTZ event, the non-driven coil is analyzed to
I
coil
I
coil
I
I
I
I
max
max
max
max
+
_
+
_
0
0
0
0
Figure 10. Full Steps (CCW)
1
1
the pointer was in a static position at default, the master could
determine the number of microsteps the device has taken by
monitoring and counting the ST4 (ST5) status bit transitions,
confirming the pointer is again in a static position.
position. An RTZ should not begin until the gauge to be
calibrated is at a static position and its pointer is at a full step
position. An attempt to calibrate a gauge, while the other is in
the process of an RTZ event, will be ignored by the device. In
most applications of the RTZR command, it is possible to
avoid a visually obvious sequential calibration by first bringing
the pointer back to the previous zero position, then re-
calibrating the pointers.
assigns the zero step position to the full step position at the
end stop location. Because the actual zero position could lie
anywhere within the full step where the zero was detected,
the assigned zero position could be within a window of ±0.5°.
An RTZ can be used to detect stall, even if the pointer already
rests on the end stop when an RTZ sequence is initiated;
however, it is recommended the pointer be advanced by at
least 24 microsteps to the nearest full step prior to initiating
the RTZ.
DEFAULT MODE
internal or external reset prior to SPI communication. An
internal reset occurs during V
is initiated by the RST pin driven to a logic [0]. With the
exception of the RTZ
Only one gauge at a time can be returned to the zero
After completion of an RTZ, the 33991 automatically
Default mode refers to the state of the 33991 after an
SINE
COSINE
2
2
CR
Analog Integrated Circuit Device Data
full step time, all of the specific pin
3
3
DD
power-up. An external reset
Freescale Semiconductor
0
0