NXP S12HZ Reference guide

Brand: NXP

Model: S12HZ

Type: Reference guide

HCS12

Microcontrollers

freescale.com

Cluster (Dashboard)

Using S12HZ256 as a

Single-Chip Solution

Designer Reference Manual

DRM084

Rev. 0

10/2006

Cluster (Dashboard) Using S12HZ256 as a Single-Chip Solution Designer Reference Manual, Rev. 0

Freescale Semiconductor 3

Freescale™ and the Freescale logo are trademarks of Freescale Semiconductor, Inc.

This product incorporates SuperFlash® technology licensed from SST.

Cluster (Dashboard) Using S12HZ256

as a Single-Chip Solution

Designer Reference Manual

by: Kenny Lam

8/16-Bit Applications Engineering, APTSPG

Freescale Semiconductor, Inc.

To provide the most up-to-date information, the revision of our documents on the World Wide Web will be

the most current. Your printed copy may be an earlier revision. To verify that you have the latest

information available, refer to:

http://www.freescale.com

The following revision history table summarizes changes contained in this document. For your

convenience, the page number designators have been linked to the appropriate location.

Revision History

Date

Revision

Level

Description

Page

Number(s)

October,

2006

0 Initial release N/A

Revision History

Cluster (Dashboard) Using S12HZ256 as a Single-Chip Solution Designer Reference Manual, Rev. 0

4 Freescale Semiconductor

Cluster (Dashboard) Using S12HZ256 as a Single-Chip Solution Designer Reference Manual, Rev. 0

Freescale Semiconductor 5

Table of Contents

Chapter 1

Introduction

1.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

1.2 System Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Chapter 2

Benefits and Features of the 9S12HZ256 Controller

2.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

2.2 Basic Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

2.3 Modes of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

2.3.1 User Modes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

2.3.2 Low-Power Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Chapter 3

Stepper Motor Drive Theory

3.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

3.2 Stepper Motor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

3.3 Stepper Motor Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

3.4 Stepper Motor Micro-Stepping Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

3.5 Stepper Stall Detection (SSD) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

3.6 LCD Driver for LCD Display Panel. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

3.7 LCD2 Panel Initialization and Checking. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

3.8 LCD2 Panel Firmware (API) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

Chapter 4

Software Integration

4.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

4.2 Micro-Stepping Control Using Internal Timer. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

4.3 Motor Running and LCD2 Panel Display Demonstration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

4.4 Cluster System Demonstration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

Chapter 5

Hardware Schematics

Chapter 6

Bill of Materials

Table of Contents

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Freescale Semiconductor 7

Chapter 1

Introduction

1.1 Introduction

This manual describes the design of a cluster board (dashboard) using Freescale’s S12HZ256

microcontroller unit (MCU). This is a single-chip design for the whole system.

The traditional cluster board uses a cross coil motor to drive the analog pointers (actuator) which move

either clockwise or counterclockwise to indicate the car speed, engine rotation speed, fuel level, engine

temperature, etc. This technology is well established and widely used throughout the world. However,

when the cross coil motor is being assembled, it requires an alignment process. The cross coil motor

displacement linearity is also a drawback in regards to the displacement accuracy (linearity), as it may

need motor fine tuning during cluster board manufacturing. In view of this, stepper motors can be one

alterative solution in this application. In addition, the Moving Magnet Technology (MMT) is more mature

for stepper motors nowadays.

The following are some advantages in having the magnet of a stepper motor move relative to a stationary

coil set.

1. The stationary drive coils are beneficial to a motor structure, as they can deal effectively with heat

dissipation.

2. There are no “flying” leads since the coils are stationary which leads to improved longevity of the

motor.

3. The weight of the stationary coils does not affect the maximum velocity of the motor.

4. There is no frictional wear out because the moving magnet concept does not make contact with

any of the stationary elements of motor.

For cluster applications in the automotive segment, Freescale offers the S12H family of devices which

can support up to six stepper motors. These devices also include, as a single-chip solution, a 32 x 4

segment LCD driver to show time and mileage updates on a LCD panel. The designers have also

integrated Stepper Stall Detection (SSD) in the new derivative of the S12HZ family. This derivative

supports up to four stepper motors with SSD.

This manual is based on the 9S12HZ256 features for designing a cluster application.

NOTE

This document is written for the user who is familiar with the S12H256

family and CodeWarrior for S12 and cluster applications. All hardware

schematic diagrams and firmware source codes are available as reference

materials.

Introduction

Cluster (Dashboard) Using S12HZ256 as a Single-Chip Solution Designer Reference Manual, Rev. 0

8 Freescale Semiconductor

1.2 System Overview

Figure 1-1 provides a pictorial overview of the system.

Figure 1-1. S12HZ256 Dashboard System

Vehicle Speed

CAN Physical

Interface

PWM

Gauge

Drivers

LED

CAN

5V Vcc

PWM

Input

Signal

Cond’n

(as req’d)

LM2902

MC33174

MC33184

TL064

Engine RPM

Engine Temp.

Batt. Voltage

Fuel Level

I/C0

I/C1

ADC5

ADC4

ADC3

ADC2

Vreg

I / O

LCD

DRIVER

MC9S12Hx

16 Bit MCU

• Integrated LCD Driver

• 32x4 (112 QFP package)

• Integrated Drive for 4 Stepper Motors

With Motor Stall Detection (MSD)

(16 hi-current PWM outputs)

• Easier PCB Routing

• Fewer Components

• Higher Reliability

• Cost Effective

Keys

RS232

SCI

Cluster (Dashboard) Using S12HZ256 as a Single-Chip Solution Designer Reference Manual, Rev. 0

Freescale Semiconductor 9

Chapter 2

Benefits and Features of the 9S12HZ256 Controller

2.1 Introduction

As shown in this chapter, the S12HZ family of devices offers an excellent complement of peripherals and

a broad range of memory and packages.

2.2 Basic Features

Some of the S12HZ family benefits are shown below. Features have been broken down by type for your

convenience.

HCS12 Core:

• 16-bit HCS12 CPU

– Upward compatible with M68HC11 instruction set

– Interrupt stacking and programmer’s model identical to M68HC11

–20-bit ALU

– Instruction queue

– Enhanced indexed addressing

• Multiplexed external bus interface (MEBI)

• Module mapping control (MMC)

• Interrupt control (INT)

• Debugger and breakpoints (DBG)

• Background debug mode (BDM)

Memory:

• 256K, 128K, 64K Flash EEPROM

• 2K, 1K byte EEPROM

• 12K, 6K, 4K byte RAM

CRG:

• Low current oscillator

• Phase locked loop (PLL)

• Reset, clocks

• Computer operating properly (COP) watchdog

• Real time interrupt

• Clock monitor

Benefits and Features of the 9S12HZ256 Controller

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10 Freescale Semiconductor

Analog-to-digital converter (ADC):

• 16 channels, 10-bit resolution

• External conversion trigger capability

• Two 1M bit per second, CAN 2.0 A, B software compatible modules:

• Five receive and three transmit buffers

• Flexible identifier filter programmable as 2 x 32 bit, 4 x 16 bit, or 8 x 8 bit

• Four separate interrupt channels for Rx, Tx, error, and wake-up

• Low-pass filter wake-up function

• Loop-back for self test operation

Timer:

• 16-bit main counter with 7-bit prescaler

• Eight programmable input capture or output compare channels

• Two 8-bit or one 16-bit pulse accumulators

Six PWM channels:

• Programmable period and duty cycle

• 8-bit 6-channel or 16-bit 3-channel

• Separate control for each pulse width and duty cycle

• Center-aligned or left-aligned outputs

• Programmable clock select logic with a wide range of frequencies

• Fast emergency shutdown input

Serial interfaces:

• Two asynchronous serial communication interfaces (SCI)

• Synchronous serial peripheral interface (SPI)

• Inter-integrated circuit interface (IIC)

Liquid crystal display driver with variable input voltage:

• Configurable for up to 32 frontplanes and 4 backplanes or general purpose input or output

• Five modes of operation allow for different display sizes to meet application requirements

• Unused frontplane and backplane pins can be used as general purpose input or output

16 high current drivers suited for PWM motor control:

• Each PWM channel switchable between two drivers in an H-bridge configuration

• Left, right, and center aligned outputs

• Support for sine and cosine drive

•Dithering

• Output slew rate control

Modes of Operation

Cluster (Dashboard) Using S12HZ256 as a Single-Chip Solution Designer Reference Manual, Rev. 0

Freescale Semiconductor 11

Four stepper stall detectors (SSD):

• Full step control during return to zero

• Voltage selector and integrator/sigma delta converter circuit

• 16-bit accumulator register

• 16-bit modulus down counter

112-Pin LQFP and 80-Pin QFP packages:

• 85 I/O lines with 5-V input and drive capability

• 5-V A/D converter inputs

• Eight key wake up interrupts with digital filtering and programmable rising/falling edge trigger

• Operating speed:

• Operation at 50 MHz equivalent to 25 MHz bus speed

Development support:

• Single-wire background debug™ mode (BDM)

• Debugger and on-chip hardware breakpoints

2.3 Modes of Operation

2.3.1 User Modes

User modes include:

• Normal and emulation operating modes

– Normal single-chip mode

– Normal expanded wide mode

– Normal expanded narrow mode

– Emulation expanded wide mode

– Emulation expanded narrow mode

• Special operating modes

– Special single-chip mode with active background debug mode

– Special test mode (Freescale use only)

– Special peripheral mode (Freescale use only)

2.3.2 Low-Power Modes

Low-power modes include:

• Stop mode

• Pseudo stop mode

• Wait mode

Benefits and Features of the 9S12HZ256 Controller

Cluster (Dashboard) Using S12HZ256 as a Single-Chip Solution Designer Reference Manual, Rev. 0

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Cluster (Dashboard) Using S12HZ256 as a Single-Chip Solution Designer Reference Manual, Rev. 0

Freescale Semiconductor 13

Chapter 3

Stepper Motor Drive Theory

3.1 Introduction

The stepper motor (MMT) is an excellent choice for cluster applications. This application employs high

current drives suited for pulse width modulator (PWM) motor control, which supports sine and cosine

drive, using the 9S12HZ256 device. Software running on the 9S12HZ256 device implements:

• Micro-stepping to achieve precise linear position

• Reduced noise

• Vibration during stepper motor running.

3.2 Stepper Motor

In theory, although a micro-stepping controller offers hundreds of intermediate positions between steps,

but it has some drawbacks. It is worth noting that micro-stepping does not generally offer great precision.

This is because of both linearity problems and the effects of static friction.

The utility of micro-stepping is limited by several considerations:

1. The angular precision achievable with micro-stepping will be limited if there is any static friction in

the system.

2. It involves the non-sinusoidal character of the torque versus shaft-angle curves on real motors.

Sometimes, this is attributed to the detent torque on permanent magnet and hybrid motors. But, in

fact both detent torque and the shape of the torque versus angle curves are products of poorly

understood aspects of motor geometry. Specifically the shapes of the teeth on the rotor and stator,

these teeth are almost always rectangular.

3. Problems arise because most applications of micro-stepping involve digital control systems. Thus,

the current through each motor winding is quantized, controlled by a digital-to-analog converter

(PWM). Furthermore, if typical PWM current limiting circuitry is used, the current through each

motor winding is not held perfectly constant, but rather, oscillates around the current control

circuit's set point. As a result, the best a typical micro-stepping controller can do is approximate the

desired currents through each motor winding.

In view of these considerations, note that the drive stepper motor running smoothly in micro-stepping

depends on the motor characteristics. The number of the steps in micro-stepping selection is also based

on the stepper motor. We chose 24 micro-stepping / step in this reference design manual as an example.

Stepper Motor Drive Theory

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3.3 Stepper Motor Control

Figure 3-1 shows a 2-phase step motor control signal. This signal switches on and off in turn and is driven

by an H-bridge as shown in Figure 3-2.

Figure 3-1. 2-Phase Step Motor Control Signal

Figure 3-2. H-Bridge

CCW

Store

tri

Supply

Phase

Stepper Motor Control

Cluster (Dashboard) Using S12HZ256 as a Single-Chip Solution Designer Reference Manual, Rev. 0

Freescale Semiconductor 15

As shown in Figure 3-3, phase A and B are driven by a square wave to move the rotor. It can be locked

at a desired position when the phase supply (square wave) stops to alter.

Figure 3-3. Basic Driving Circuit for Two Phase Step Motor

In order to drive a moving stepper motor, the S12H family offers a simple instruction to control step

movement. The example below, uses motor channel 0 to control the stepper motor moving forward. The

phase supply sequences are as follows:

Phase A B

void eat_time(int time) //eat time

{

while(time--!=0){}

}

void step_move() //step move

{

MCDC0H &=~0x80; //channel 0 (A = 0, /A = 1) Step 0

MCDC1H |=0x80; //channel 1 (B = 1, /B = 0)

eat_time(0x2000); //delay

MCDC0H &=~0x80; //channel 0 (A = 0, /A = 1) Step 1

MCDC1H &=~0x80; //channel 1 (B = 0, /B = 1)

eat_time(0x2000); //delay

MCDC0H |=0x80; //channel 0 (A = 1, /A = 0) Step 2

MCDC1H &=~0x80; //channel 1 (B = 0, /B = 1)

eat_time(0x2000); //delay

MCDC0H |=0x80; //channel 0 (A = 1, /A = 0) Step 3

MCDC1H |=0x80; //channel 1 (B = 1, /B = 0)

eat_time(0x2000); //delay

}

Gnd

Vdd

Phase A

Vdd

Gnd

Phase B

Rotate

Stepper Motor Drive Theory

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16 Freescale Semiconductor

Please refer to the firmware project (1. StepMove) for more detailed information. See Figure 3-4.

Figure 3-4. StepMove Screen

Stepper Motor Micro-Stepping Control

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Freescale Semiconductor 17

3.4 Stepper Motor Micro-Stepping Control

The utility of micro-stepping is limited by at least three considerations.

1. Motor static friction

2. Non-sinusoidal character of the torque versus shaft-angle, each motor

3. Winding is quantized, controlled by a digital-to-analog converter (PWM)

The most common control algorithm is adopted to use sinusoidal current to drive micro-stepping. One

complete sinusoidal wave is equivalent to four steps in a 2-phase motor.

Phase A is driven by a PWM as sinusoidal to move the rotor. It can also be locked at a desired position

when the phase supply stops to alter. The stepper motor can be held by the supply current from the driver

as static holding torque.

Phase A and B are driven by a sinusoidal wave to move the rotor. It can be locked at a desired position

when the phase supply (sinusoidal wave) stops to alter.

To drive stepper motor moving, the S12H family can use a simple look-up table to implement a sinusoidal

signal to drive micro-stepping movement.

Refer to Figure 3-5 and Figure 3-6.

Figure 3-5. Micro-Stepping Sinusoidal Control

CCW

Stepper Motor Drive Theory

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18 Freescale Semiconductor

Figure 3-6. Micro-Stepping Sinusoidal Control with PWM

Please refer to the firmware project (2. MicroStepMove) for more detailed information. See Figure 3-7.

Figure 3-7. MicroStepMove Screen

Suppl

PWM

Phase

PWM

/PWM

Phase

Store trip

Stepper Stall Detection (SSD)

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Freescale Semiconductor 19

3.5 Stepper Stall Detection (SSD)

This module provides a built-in circuit to detect the induced voltage on the non-driven coil of a stepper

motor. The back EMF can be measured by an internal ADC module, which can integrate the induced

voltage on the non-driven coil, and store its results to a16-bit accumulator register. The internal 16-bit

modulus down counter can be used to monitor the blanking time and the integration time. The value in

the 16-bit accumulator represents the change in linked flux. It can be compared to a stored threshold to

distinguish whether the motor reaches the home position. Values above the threshold indicate a moving

motor, in which case the pointer can be advanced another full step in the same direction and integration

repeated. Values below the threshold indicate a stalled motor, home position is reached.

See Figure 3-8.

Figure 3-8. Stepper Stall Detection Flowchart

Advanced Motor Pointer

Initialized SSD

Start Blinking

End of Start Blinking

Yes

Start Integration

End of Integration

Yes

Stall Detection

Disabled SSD

Stepper Motor Drive Theory

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20 Freescale Semiconductor

Please refer to the firmware project (3. StepperStallDetection) for more detailed information. See

Figure 3-9.

Figure 3-9. StepperStallDetection Screen

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