DEMO9S08QD4 Freescale Semiconductor, DEMO9S08QD4 Datasheet - Page 7

• Manufacturer Part Number: DEMO9S08QD4
• Description: BOARD DEMO FOR MC9S08QD FAMILY
• Manufacturer: Freescale Semiconductor
• Type: MCUr

Specifications of DEMO9S08QD4

• Contents: Board, Cable, CD
• Processor To Be Evaluated: MC9S08QD
• Data Bus Width: 8 bit
• Interface Type: USB
• Silicon Manufacturer: Freescale
• Core Architecture: HCS08
• Core Sub-architecture: HCS08
• Silicon Core Number: MC9S08
• Silicon Family Name: S08QD
• Rohs Compliant: Yes
• For Use With/related Products: MC9S08QD2, MC9S08QD4
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

The measured time between point 1 and point 2 is called a
and point 3 is called
After the duty cycle is calculated, the coils of the motor are controlled through port A, channels 0 to 3. As
established previously there are one hundred positions available. This means that the required position is
equal to the duty cycle.
If the microcontroller detects a change in the value of the duty cycle, it moves the stepper to the required
position. Each time the duty cycle varies, channels are strictly toggled in a specific sequence:
In
is equal to one mechanical step. Therefore, to create an image of port A behavior in time, an example is
shown as in
Freescale Semiconductor
PORT A
Table 1
are values that obtain the step by step movement of the stepper motor. Each transition of port A
Forward
Figure
0x0A
0x0A
0x09
0x05
0x06
0x09
0x05
0x06
Driving a Stepper Motor Based on the MC9S08QD4 and Other 8-bit Families, Rev. 0
9.
Duty_Cycle_H
COIL
A1
0
1
1
0
0
1
1
0
COIL
A2
0
0
1
1
0
0
1
1
Duty
Required_position = Duty_Cycle
COIL
Table 1. Stepper Motor Transitions
_
. To find the duty cycle of the signal calculate:
B1
1
0
0
1
1
0
0
1
Cycle
COIL
=
B2
0
0
1
1
0
0
1
1
(
Duty
Frequency
_
Cycle
Controlling the Stepper Based on an Input Signal (PWM)
PORT A
Frequency
_
H
)
100
Backward
. The measured time between point 2
0x0A
0x0A
0x06
0x05
0x09
0x06
0x05
0x09
COIL
A1
1
0
0
1
1
0
0
1
COIL
A2
0
1
1
0
0
1
1
0
COIL
B1
1
1
0
0
1
1
0
0
Eqn. 1
Eqn. 2
COIL
B2
0
0
1
1
0
0
1
1
7