MCZ33976EGR2 Freescale Semiconductor, MCZ33976EGR2 Datasheet - Page 30

• Manufacturer Part Number: MCZ33976EGR2
• Description: IC DRIVER DUAL GAUGE SPI 24-SOIC
• Manufacturer: Freescale Semiconductor
• Type: Serial Peripheral Interface (SPI) Dual Step Motor Gauge Driverr

Specifications of MCZ33976EGR2

• Applications: Stepper Motor Driver, 2 Phase
• Number Of Outputs: 2
• Current - Output: 100mA
• Voltage - Supply: 6.5 V ~ 26 V
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: 24-SOIC (7.5mm Width)
• Supply Current: 4 mA
• Maximum Operating Temperature: + 125 C
• Mounting Style: SMD/SMT
• Minimum Operating Temperature: - 40 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Voltage - Load: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

Table 30. Velocity Table (continued)
Internal Clock Calibration
velocities, acceleration, and Return To Zero Pointer speeds)
depend upon a precise, consistent time reference to control
the pointer accurately and reliably. Generating accurate time
references on an integrated circuit can be accomplished. For
example trimming can be used however, it tends to be costly
due to the large amount of die area required for trim pads.
Another possibility is an externally generated clock signal;
however, this requires a dedicated pin on the device and
controller. An alternate approach would require the use of an
additional crystal or resonator, which is expensive.
independent and area efficient; however, it can vary by as
much as ±35 percent due to process variation. Using the
existing SPI inputs and the precision timing reference already
available to the microcontroller, the 33976 allows more
accurate clock calibration to within ±10 percent.
a logic [1] to PECCR bit PE3 (see
8.0 µs calibration pulse is then provided by the controller to
30
33976
FUNCTIONAL DEVICE OPERATION
LOGIC COMMANDS AND REGISTERS
Velocity
Position
SCLK
Timing-related functions on the 33976 (e.g., pointer
The internal clock in the 33976 is temperature
Calibrating the internal 1.0 MHz clock is initiated by writing
66
67
68
69
70
71
72
73
74
75
CS
SI
Steps (µs)
Between
D15
Time
414
410
406
403
399
396
393
389
386
383
(µSteps/s)
Velocity
2415.5
2439.0
2463.1
2481.4
2506.3
2525.3
2544.5
2570.7
2590.7
2611.0
Figure 10. Gauge Enable and Clock Calibration Example
Figure
10, page 30). The
PECCR Command
Position
Velocity
142
143
144
145
146
147
148
149
150
151
Steps (µs)
Between
Time
267
266
265
264
263
262
261
260
259
258
ideally result in an internal 33976 clock speed of 1.0 MHz.
The pulse is sent on the
word is sent. During the calibration, no other SPI lines should
be toggled. At the moment the
logic [1] to logic [0], an internal 7-bit counter counts the
number of cycles of an internal, 8.0 MHz clock. The counter
stops when the
The value in the counter represents the number of cycles of
the 8.0 MHz clock occurring in the 8.0 µs window; it should
range from 32 to 119. An offset is added to this number to
help center or skew the calibrated result to generate a
desired maximum or nominal frequency. The modified
counter value is truncated by 4 bits to generate the calibration
divisor, which should range from 4 to 15. The 8.0 MHz clock
is divided by the calibration divisor, resulting in a calibrated
1.0 MHz clock. If the calibration divisor lies outside the range
of 4 to 15, the 33976 flags the CAL bit in the device status
register, indicating the calibration procedure was not
successful. A clock calibration is allowed only if the gauges
are disabled or the pointers are not moving, as indicated by
status bits MOV1 and MOV0
(µSteps/s)
Velocity
3745.3
3759.4
3773.6
3787.9
3802.3
3816.8
3831.4
3846.2
3861.0
3876.0
CS
pin transitions from logic [0] to logic [1].
D0
Analog Integrated Circuit Device Data
CS
Position
Velocity
218
219
220
221
222
223
224
225
pin immediately after the SPI
(Table
CS
8.0 µs Calibration Pulse
pin transitions from
Freescale Semiconductor
20, page 21).
Steps (µs)
Between
Time
212
211
211
210
210
209
209
208
(µSteps/s)
Velocity
4717.0
4739.3
4739.3
4761.9
4761.9
4784.7
4784.7
4807.7