MCZ33977EGR2 Freescale Semiconductor, MCZ33977EGR2 Datasheet - Page 26

• Manufacturer Part Number: MCZ33977EGR2
• Description: IC DRIVER SGL GAUGE SPI 24-SOIC
• Manufacturer: Freescale Semiconductor
• Type: Single Gauge Driverr

Specifications of MCZ33977EGR2

• Applications: Stepper Motor Driver, 2 Phase
• Number Of Outputs: 1
• 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)
• Operating Supply Voltage: 4.5 V to 5.5 V
• Supply Current: 1.8 mA
• Mounting Style: SMD/SMT
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Voltage - Load: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

(1111) in increments of 4.096 ms (refer to
is multiplied by the factor M, defined by bits RC12:RC11. The
product is then added to the blanking time, selected using bit
RC4, to generate the full step time. The multiplier selected
with RC12:RC11 will be 1 (00), 2 (01), or 4 (10) as illustrated
in the equations below. Note that the RC12:RC11 value of 8
(11) is not recommended for use in a product design
application, because of the potential for an RTZ accumulator
internal overflow, due to the long time step. The blanking time
is either 512 µs when RC4 is Logic [0], or 768 µs when it is
Logic [1].The full step time is calculated using the following
equations:
When D3:D0 (RC3:RC0)
When D3:D0 (RC3:RC0) = 0000
step time when the RC3:RC0 = 0000. The full step time
default value after a logic reset is 12.80 ms (RC12:RC11 =
00, RC4 = 0, and RC3:RC0 = 0011).
the pointer speed is 1/(Full Step x 2) deg/s.
integrating the EMF present in the non-driven coil during the
RTZ event. The integration circuitry is implemented using a
Sigma-Delta converter resulting in the placement of a value
in the 15-bit RTZ accumulator at the end of each full step. The
value in the RTZ accumulator represents the change in flux
(RC12:RC11) Bits D12:D11
determine the full step time and, therefore, the rate at which
the pointer will move during an RTZ event. The values of
D12:D11 determine the multiplier (M) used in equation (1)
(refer to the previous page).
(RC10:RC5) Bits D10:D5
integration accumulator to adjust the detection threshold.
26
33977
Table 13. Return to Zero Register Configuration Register (RTZCR)
FUNCTIONAL DEVICE OPERATION
LOGIC COMMANDS AND REGISTERS
Bits
Read
Write
Full Step (t) = ∆t x M+ blanking (t)
Full Step (t) = blanking (t) + 2.048 ms
Note: In equation (2), a 2.048 ms offset is added to the full
If there are two full steps per degree of pointer movement,
Detecting pointer movement is accomplished by
The bits in
These bits, along with RC3:RC0 (D3:D0) and RC4 (D4),
RC12:RC11 = M; default value = 00
• 00 = 1
• 01 = 2
• 10 = 4
• 11 = 8 (Not to be used for design)
These bits determine the value preloaded into the RTZ
RC12
D12
–
Table 13
RC11
D11
–
are write-only.
=
0000
RC10
D10
–
RC9
D9
–
(1)
Table
(2)
RC8
D8
14). The ∆t
–
RC7
Address 101
D7
–
RC6
and is compared to a threshold. Values above the threshold
indicate a pointer is moving. Values below the threshold
indicate a stalled pointer, thereby resulting in the cessation of
the RTZ event.
two’s complement. After a full step of integration, a sign bit of
0 is the indicator of an accumulator exceeding the decision
threshold of 0, and the pointer is assumed to still be moving.
Similarly, if the sign bit is Logic [1] after a full step of
integration, the accumulator value is negative and the pointer
is assumed to be stopped. The integrator and accumulator
are initialized after each full step. If the PECCR command is
written to clock out the RTZ accumulator values via the SO,
the OD14 bit corresponds to the sign bit of the RTZ
accumulator.
preloaded accumulator for specific gauge, pointer, and full
step combinations. Bits RC10:RC5 are used to offset the
initial RTZ accumulator value, properly detecting a stalled
motor. The initial accumulator value at the start of a full step
of integration is negative. If the accumulator was correctly
preloaded, a free moving pointer will result in a positive value
at the end of the integration time, and a stalled pointer will
result in a negative value. The preloaded values associated
with each combination of bits RC10:RC5 are illustrated in
Table
resulting in an accumulator MSB to Logic [1] when the motor
is stalled. For the default mode, after a power-up or any reset,
the 33977 device sets the accumulator value to -1.
Values range from -1 (00000000) to -1009 (11111111) as
shown in
(RC4) Bit D4
The default value = 0
(RC3:RC0) Bits D3:D0
(D4), determine the time variables used to calculate the full
step times with equations (1) or (2) illustrated above.
RC3:RC0 determines the ∆t time. The ∆t values range from 0
(0000) to 61.440 ms (1111) and are shown in
default ∆t is 0 (0011).
used to calculate the full step time if RC3:RC0 = 0000. Use
equation (1) for all other combinations of RC3:RC0.
D6
–
The RTZ accumulator bits are signed and represented in
Accurate pointer stall detection depends on a correctly
This bit determines the RTZ blanking time (blanking (t)).
• 0 = 512
• 1 = 768
These bits, along with RC12:RC11 (D12:D11) and RC4
Note: Equation (2) (refer to the preceding page) is only
15. The accumulator should be loaded with a value
RC5
D5
Table 15,
–
µ
µ
s
s
RC4
D4
–
the default value = 000000.
Analog Integrated Circuit Device Data
RC3
D3
–
Freescale Semiconductor
RC2
D2
–
RC1
D1
Table 14.
–
RC0
D0
–
The