MC33991DW 查看數據表（PDF） - Freescale Semiconductor

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MC33991DW

Gauge Driver Integrated Circuit

Freescale Semiconductor 

TIMING DESCRIPTIONS AND DIAGRAMS

DEVICE FUNCTIONAL DESCRIPTION

• 0 = Gauge 1 position has not changed since the last SPI

command

• 1 = Gauge 1 pointer position has changed since the last

SPI command

ST4–Gauge 0— Movement since last SPI communication.

A logic [1] on this bit indicates the Gauge 0 pointer position

has changed since the last SPI command. The master

confirms that the pointer is moving as commanded.

• 0 = Gauge 0 position has not changed since the last SPI

command

• 1 = Gauge 0 pointer position has changed since the last

SPI command

ST3–RTZ1—Enabled successful or disabled. A logic [1]

on this bit indicates Gauge 1 is in the process of returning to

the zero position as requested with the RTZ command. This

bit continues to indicate a logic [1] until the SPI message

following a detection of the zero position, or the RTZ feature

is commanded OFF using the RTZ message.

• 0 = Return to Zero disabled

• 1 = Return to Zero enabled successful

ST2–RTZ0—Enabled successful or disabled. A logic [1]

on this bit indicates Gauge 0 is in the process of returning to

the zero position as requested with the RTZ command. This

bit continues indicating a logic [1] until the SPI message

following a detection of the zero position, or the RTZ feature

is commanded OFF, using the RTZ message.

• 0 = Return to Zero disabled

• 1 = Return to Zero enabled successful

ST1–Gauge 1 Junction over temperature. A logic [1] on

this bit indicates coil drive circuitry dedicated to drive Gauge

1 exceeded the maximum allowable junction temperature

since the last SPI communication. Additionally, the same

indication signals the circuitry Gauge 1 is disabled. It is

recommended the pointer be re-calibrated using the RTZ

command after re-enabling the gauge using the PECR

command. This bit remains logic [1] until the gauge is

enabled.

• 0 = Temperature within range

• 1 = Gauge 1 maximum allowable junction temperature

condition has been reached

ST0–Gauge 0— Junction over temperature. A logic [1] on

this bit indicates coil drive circuitry dedicated to drive Gauge

0 exceeded the maximum allowable junction temperature

since the last SPI communication. Additionally, the same

indication signals the circuitry Gauge 0 is disabled. It is

recommended the pointer be re-calibrated using the RTZ

command after re-enabling the gauge, using the PECR

command. This bit remains logic [1] until the gauge is re-

enabled.

• 0 = Temperature within range

• 1 = Gauge 0 maximum allowable junction temperature

condition has been reached

DEVICE FUNCTIONAL DESCRIPTION

STATE MACHINE OPERATION

The two-phase stepper motor is defined as maximum

velocity and acceleration, and deceleration. It is the purpose

of the stepper motor state machine is to drive the motor with

maximum performance, while remaining within the motor’s

velocity and acceleration constraints.

When commanded, the motor should accelerate

constantly to the maximum velocity, then decelerate and stop

at the desired position. During the deceleration phase, the

motor should not exceed the maximum deceleration. A

required function of the state machine is to ensure the

deceleration phase begins at the correct time, or position.

During normal operation, both stepper motor rotors are

microstepped with 24 steps per electrical revolution. See

Figure 6. A complete electrical revolution results in two

degrees of pointer movement. There is a second and smaller

state machine in the IC controlling these microsteps. This

state machine receives clockwise or counter-clockwise index

commands at intervals, stepping the motor in the appropriate

direction by adjusting the current in each coil. Normalized

values provided in Table 13.

Analog Integrated Circuit Device Data

Freescale Semiconductor

33991

19

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