Other Chapters

From the text by Valvano: Introduction to Embedded Systems: Interfacing to the

Freescale 9S12

Chapter 8 Seril and Parallel Port Interfacing

• 8.1 General Introduction– Mechanical Design of Physical Components– Analog and digital electronics used to connect the

physical components.– Low level software that transforms the mechanical

and electrical devices into objects that perform the desired tasks.

8.2 Serial Communications Interface, SCI

• 8.2.1 RS232 Protocol

• 8.2.2 Transmitting in Asynchronous Mode

• 8.2.3 Receiving in Asynchronous Mode

• 8.2.4 9S12 Details– SCI Baud Rate can be set using the SCI0BD– SCI control register is SCI0BD– Table 8.4 has more details– Program 8.1 shows initialization

8.3 Synchronous Peripheral Interface, SPI

• Low-bandwidth protocol, up to 100,000 bps• 8.3.1 SPI Fundamentals• 8.3.2 SPI Details• 8.3.3 9s12DPS512 Module Routing Register (for

port pin configurations)• 8.3.4 8-bit DAC (external)

8.4 Scanned Keyboards

• A scanned interface has switches placed in a row/column matrix

8.5 Parallel Port LCD Interface with the HD44780

• LCD Displays are widely used and have replaced most of the “LED” interfaces.

8.6 Binary Actuators

• 8.6.1 Interface– Relays, solenoids, and DC Motors have

similar electrical interfaces.– There is a coil that the computer drives (or not

drives) current through.

• 8.6.2 Electromagnetic and Solid-state Relays

8.7 Pulse-Width Modulation

• Duty cycle of a fixed frequency digital output wave is changed to provide power in a variable manner.

8.8 Stepper Motors

• A motor controls the rotational position, instead of the rotational speed.

Ch. 9 Interrupt Programming and Real-Time Systems

• 9.1 I/O Synchronization– Software Latency– Real-Time System Definition

• A system that can guarantee a worst case latency.• Software Response Time is small and bounded.

• 9.2 Interrupt concepts– “An interrupt is the automatic transfer of software execution in response

to a hardware event that is asynchronous with the software execution.”• 9.3 Key Wakeup Interrupts

– A wakeup is an interrupt request on the rising/falling of an external input signal.

Ch.9 (cont.)

• 9.4 Periodic Interrupt Programming• 9.5 Real-Time Interrupt (RTI)• 9.6 Timer Overflow, Output Compare, and Input

Capture• 9.7 Pulse Accumulator• 9.8 Direct Memory Access• 9.9 Hardware Debugging Tools (Logic Analyzer

and In-Circuit Emulator or ICE)• 9.10 Profiling

– A debugging process that collects the time history of strategic variables.

Chapter 10 Numerical Calculations

• 10.1 Fixed-Point Numbers

• 10.2 Extended Precision Calculations

• 10.3 Expression Evaluation

• 10.4 IEEE Floating-Point Numbers

Ch. 11 Analog I/O Interfacing

• 11.1 Approximating Continuous Signals in the Digital Domain

• 11.2 Digital to Analog Conversion• 11.3 Music Generation• 11.4 Analog to Digital Conversion• 11.5 Multiple Access Circular Queues• 11.6 Real-Time Data Acquisition• 11.7 Control Systems

Ch. 12 Communication Systems• 12.1 Introduction• 12.2 Reentrant programming and Critical

Sections– A program segment is reentrant if it can be

concurrently executed by two (or more) threads.

• 12.3 Interthread Communication and Synchronization

• 12.4 Serial Port Interface Using Interrupt Synchronization

• 12.5 Distributed Systems

Ch.12 (cont.)• 12.6 Design and Implementation of a Controller Area

Network (CAN)– CAN is a high-integrity serial data communication bus that is used

for real-time applications.– Speeds up to 1Mbps

• 12.7 Inter-Integrated Circuit (I2C) Interface– 2-wire interface (speeds up to 100-400 kpbs)—Version 1– Version 2—speeds up to 2.4 Mbps. (not supported by 9S12)

• 12.8 Wireless Communication (page 470)