A 3-SPEED STEPPER MOTOR

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Carmel Hunt
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1 ECE 36 Projects; Stepper Motor 1 of 5 A 3-SPEED STEPPER MOTOR 1. Design a microprocessing system to implement a 3-speed stepper motor. Your design is constrained to use the parts shown in Fig. 1 and described as follows: STEPPER MOTOR The stepper motor has a dial and eight notches. The dial may be controlled to rotate either clockwise (CW) or counter clockwise (CCW) by one notch at a time. To continually rotate the dial clockwise, the following sequence of 4-bit numbers should be applied to the stepper motor at the D3-D0 inputs: 5, 6,, 9, 5, 6,, 9,... To continually rotate the dial counter clockwise, the sequence should be reversed. For example, if the last 4-bit number applied to the motor was 9, then the sequence should be, 6, 5, 9,, 6, 5, 9,... Each 4-bit number input to the motor causes the motor to move one notch. The time between each 4-bit number applied to the motor determines the speed of rotation. CONTROL PANEL The Control Panel provides a means for a user to control the stepper motor, through seven buttons: START: when the START button is selected, the motor should rotate clockwise at the currently selected speed (L, M, or H) in the currently selected direction (CW or CCW). Initially, the clockwise direction and low speed should be established as default if the user does not select them first. STOP: when the STOP button is selected, the motor should stop rotating. CW: The CW button selects to rotate the motor in the clockwise direction. CCW: The CW button selects to rotate the motor in the counter clockwise direction. L: the L button selects the low speed of rotation: 2 Revolutions Per second (RPs). (See Q 1.9) M: the M button selects the medium speed of rotation: 4 RPs. (See Q 1.9) H: the H button selects the high speed of rotation: 6 RPs. (See Q 1.9) TIMER A hardware timer shall be used to control the speed of rotation of the stepper motor. The timer has an internal counter, a configuration register, and a comparator. If and when enabled, the timer increments the internal counter at the rate determined by the signal input at the CLK pin. When the internal counter reaches the number specified in the configuration register (C5-C0), the output signal RO is asserted, the internal counter resets to and resumes counting up again. The assertion of the RO signal is defined by a LOW-HIGH-LOW pulse, where the HIGH time of the pulse is exactly 2μs. The configuration register is defined by the following bits: S/Pn: The S/Pn bit enables (S/Pn=1) or disables the timer (S/Pn=0). Rn: Rn=0 resets the internal counter to C5-C0: the C5-C0 bits represent the number with which the internal counter will be compared. (Do not use C5-C0 = : not defined.) The configuration register may be written to by applying the 8-bit configuration word on the CR7-CR0 pins, and then providing a positive edge on the CRW pin.

2 ECE 36 Projects; Stepper Motor 2 of 5 CONTROL PANEL KP START CP1 STOP CP2 CP3 CW CCW D0 D1 D2 D3 STEPPER MOTOR Dial CW L M H Table 1: Control Panel Truth Table. Key CP2 CP1 CP0 None Start Stop CW CCW CRW CLK Shaft Notch CCW TIMER CR7 CR6 CR5 CR4 CR3 CR2 CR1 CR0 Rn C5 C4 C3 C2 C1 C0 Comparator S/Pn RO 2μs Fig. 1. The Control Panel, Stepper Motor, and Timer must be used in your design. Note: all of the signals formthe Control Panel and Timer RO, and all of the signals controllign teh Stepper Motor and Timer must be processed by your microprocessor software. You may use other parts as follows: Optional Parts (no other devices are permitted) A basic micro-processor (You may use the HC11 of HS12 instruction set). Three 512x8 ROM chips. Each ROM chip has two chip selects (CS0 and CS1). One 128x8 ROM chip, with one active low chip select (CS). Eight 32Kx8 RAM chips. Each RAM chip has four active high chip selects (CS3-CS0). One 64x8 RAM chip, with one active low chip select (CS). Many 4-port PCIAs. Each PCIA has one active low chip select (CS). An ATD converter, having 8-bit resolution and a fixed sampling frequency of 8 khz. Two DTA converters, which convert 8-bit numbers to the range of 0V to 5V in 256 steps. Logic gates, resistors, capacitors, amplifiers, 128 ms counter, etc. Several clocks: 32 Hz clock; 64 Hz clock; 128 Hz clock; 1 MHz clock; 2 MHz clock; and 1 GHz clock. Note: You must choose an appropriate speed clock for your microprocessor. Also, you must choose an appropriate speed clock for the timer to effect the required speed of

3 ECE 36 Projects; Stepper Motor 3 of 5 the stepper motor (i.e., 2 RPs, 4 RPs, and 6 RPs). To determine the parameters of the TIMER, (See Q 1.9).

4 ECE 36 Projects; Stepper Motor 4 of Draw a system block diagram of your design. Show all pertinent connections of your devices to the microprocessor, using the system bus format. Your solution will be marked for completeness, readability and legibility. Cost is an important constraint, so use the absolute minimum size and minimum number of devices. 1.2 Design an address decoder for your system. Your design must adhere to the address decoding guidelines, as given and discussed in this course. Your design must adapt to the available number and type of chip select pins on the given devices. Give the chip select Boolean equation for each device in your system. Design the address decoder circuits and show them in your block diagram. Give the starting address and the ending address for each device. 40 or or Create a flow chart that explains how your software configures the PIA for this application. For each PIA data pin that you configure as input or output, explain why the bit is configured that way (i.e., explain its function), and to which device the data pin will be connected. For each control pin of the PIA you are using (CA1, CB1, etc.), identify to which pin of the I/ O device the PIA control pin is connected, and explain why. Your flow chart should allow a reader to determine exactly, in detail, what your software does. If your design does not use PIA, then skip this question. 1.4 Create a flow chart that explains your main program. Include any subroutines and branches. If your design does use an Interrupt Service Routine (ISR), do not include it here (Draw it on next page). If your design does not use an ISR, then this question will be marked out of 80 marks. Your flow chart should allow a reader to determine exactly, in detail, what your software does. 1.5 Create a flow chart that describes your Interrupt Service Routine (ISR) for this application. Include all details, such as subroutines and branches. Your flow chart should allow a reader to ascertain exactly, in detail, what your software does. If your design does not use an ISR, then skip this question (in this case, this question will not be marked).

5 ECE 36 Projects; Stepper Motor 5 of Write an assembly language program for your 3-speed stepper motor microprocessing system. Include all assembly language: main program, ISR, branches, subroutines, memory allocation (for variables, constants, and stack), and equates. Comment your code Determine the maximum size of your stack. Show the contents of the stack when it has reached the maximum size in the space provided below. 1.8 What is the maximum number of cycles your program requires to make the stepper motor dial move one notch? Show details of your calculation in the space provided. Give line numbers of each instruction that is included in your calculation. Explain each component in your calculation. 1.9 Determine the parameters for the TIMER device in order to effect the required speed of the stepper motor (i.e., 2 RPs, 4 RPs, and 6 RPs). In other words, from the available list of parts, what clock device have you chosen for the TIMER? Also, what values of the bits C5-C0 does your design use to obtain the speeds 2 RPs, 4 RPs, and 6 RPs? (Fill in the Table 23.2). If you don t know how to answer this question, then use the values C5-C0 = for HIGH speed, C5-C0 = for MEDIUM speed, and C5-C0 = for LOW speed. However, if you use these values, then you will receive 0 marks for this question. Table 2: TIMER Parameters SPEED RPs C5-C0 LOW 2 MEDIUM 4 HIGH 6

8254 is a programmable interval timer. Which is widely used in clock driven digital circuits. with out timer there will not be proper synchronization

8254 is a programmable interval timer. Which is widely used in clock driven digital circuits. with out timer there will not be proper synchronization between two devices. So it is very useful chip. The