About the Book
Publicity about the Chinese edition.
Designing
Embedded Systems with PIC Microcontrollers - Principles & Applications
Book Support Page
Home (Embedded Know-How)
This page carries support information
on the book, links to useful
sites, and errata. The book is available in original English, and in Chinese
Translation.
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Why I Wrote this Book About the Book |
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Publicity about the Chinese edition. |
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Why I Wrote this Book
Every year I found myself
supervising a number of student projects which involved the design of some sort
of AGV (Autonomous Guided Vehicle). Too many of these projects never "got off
the ground", as students made non-optimum design decisions in areas like vehicle
geometry, motor and power supply selection, and so on. From this sense of
frustration the Derbot project arose. The aim of the
Derbot was to give students a core AGV design, which gave them the basic chassis
and electronics, but then allowed them flexibility to customise in the way they
saw fit. Later I starting approaching publishers with the idea of writing a book
which used the Derbot as the main example design. The first goal was to write a
short book. However ideas kept getting added, leading to what is now a pretty
solid book. In its final form the book brings together both the experience
we have had with the Derbot, alongside a wealth of professional embedded design
experience.
About the Book
This book is a hands-on introduction to the principles and practice of embedded
system design using the PIC microcontroller. Packed with helpful examples and
illustrations, it gives an in-depth treatment of microcontroller design,
programming in both assembly language and C, and features advanced topics such
as networking and real-time operating systems. It is accompanied by a CD-ROM
containing copies of all programs and software tools used in the text and a
'student' version of the C complier.
Designing Embedded Systems with PIC Microcontrollers: Principles and
Applications is ideal for students of electronics, mechatronics and computer
engineering. Engineers in industry and informed hobbyists will also find this
book a valuable resource when designing and implementing both simple and
sophisticated embedded systems using the PIC Microcontroller.
* Gain the knowledge and skills required for developing today's embedded systems,
through use of the PIC microcontroller.
* Explore in detail the 16F84A, 16F873A and 18F242 microcontrollers as examples
of the wider PIC family.
* Learn how to program in Assembler and C.
* Work through sample designs and design ideas, including a robot in the form of
an autonomous guided vehicle (the Derbot).
* Accompanied by a CD-ROM containing copies of all programs and software tools
used in the text and a 'student' version of the C complier.
Buy the Book through the Internet
from
Elsevier Catalogue
from
Amazon (USA)
from
Amazon (Canada)
from Turing Books (Chinese Edition)
Support Information, by Chapter
Notes:
All information on building the Derbot AGV appears in the Derbot
site section.
Errata (except for tiny typos) appear in chapter sections.
Select the chapter you want to go to.
| Chapter 1 | Chapter 7 | Chapter 13 | Chapter 19 |
| Chapter 2 | Chapter 8 | Chapter 14 | Chapter 20 |
| Chapter 3 | Chapter 9 | Chapter 15 | Appendix 2 |
| Chapter 4 | Chapter 10 | Chapter 16 | Appendix 3 |
| Chapter 5 | Chapter 11 | Chapter 17 | Appendix 5 |
| Chapter 6 | Chapter 12 | Chapter 18 | Book CD |
Chapter 1
The book was completed just before
Microchip entered the world of Digital Signal Processing, or of 16- and 32-bit
microcontrollers. Therefore Section 1.5 is a little dated now. Go
here for an up-to-date overview of Microchip microcontroller products.
Chapter 3
Errata
Page 60, 4th line: the last word should read "crystal", not "capacitor".
Page 57: In equation (3.4) and the equation directly above which leads into it, ROH should be replaced by ROL.
| Figure 1.3 in the book shows a picture of the pingpong circuit made using a pcb. The circuit diagram appears in Appendix 2. A more compact version, now with connection for PICkit 2 programming, is shown below left. It can also be constructed on stripboard, as shown below centre; a more compact component distribution is of course possible. Finally it can be built on a prototyping system, as below right (with thanks to Jim Wicks). Click on any image to expand. | ||
|
|
Find instructions to make this version here. |
|
Programming Exercise 5.7
It is intended that this runs with the original Fibonacci program, i.e.
Program Example 5.6. If run with the version of Program Example 5.7 a stopwatch
value of 226us is reported.
A Note on Case Sensitivity in MPLAB
From Program Example 5.7 the book starts using Include Files, described on
Page 106. From this point case sensitivity in MPLAB must be disabled, as the
Include File uses symbols written in upper case, while the book programs are
written in lower case. Access case sensitivity (in MPLAB ver. 7.22) by clicking
Project -> Build Options -> Project ->MPASM Assembler (or Project
-> Build Options -> project name). An example of
Assembler errors if this is not done is seen in
Development Tools: Frequently Asked Questions.
A Note on Trace Displays
Figure 5.9 in the book shows an MPLAB Version 7.20 screen print. It has the line
numbers running from 0 to +142, where the breakpoint occurs.
More recent versions of MPLAB have the line numbers counting up from a negative number, to line 0, where the breakpoint occurs. Both versions display from top to bottom. The difference is that one ends on line 0, while the other starts there!
Another difference is that the Trace display in Version 7.20 treats all branches as single line instructions, while later versions gives them two lines each. It's as if this version is actually showing the flow of instructions in the pipeline. Thus every branch instruction is accompanied by a NOP. Therefore, for the same Trace operation, there are more lines in a Version 7.4 Trace, compared to a Version 7.20 one.
The equivalent screen image for Figure 5.9, using Version 7.22, is shown below. Notice the NOP in line -5 which follows the GOTO instruction. The total number of lines in this Trace is 165. If you count all of these NOPs, and subtract that from 165, you get to the 142 lines of Figure 5.9. Interestingly, the number of cycles is the same in each print, except that the book print does not indicate that the final GOTO instruction will take 2 cycles.
Errata
Page 92: the explanation relating btfsc and btfss in the
second to last paragraph is reversed.
Page 96: first line last paragraph, should read "The simple delay loop
of Program Example 5.2...."
Page 108: Program Example 5.9, last two lines should read:
bfbclr
porta,4,wait ;go to wait if right paddle pressed
bfbclr porta,3,wait ;go to wait if left paddle pressed
(i.e. bfbclr macro used on both lines)
back to top
Chapter 6
Errata
Page 126, Simulation Exercise 6.1:
The
reset state of the INTEDG bit and its effect is described "up side down"
in this exercise.
The
reset state of the INTEDG bit is logic 1. The relevant sentences can be
rewritten:
... Now “fire” the RB0 pin, setting RB0 high, and an interrupt sequence should be instigated as you single step further. See the Hardware Stack change, program execution transfer to the ISR, and on ISR completion the program resuming after the instruction where it was interrupted. Fire the RB0 pin again (returning it to 0), and continue stepping. This will cause no change to program execution, as the interrupt edge response will be positive-edge triggered only (the INTEDG bit has been left at Reset value of 1). Try changing the INTEDG bit (to 0), as shown in the program....
Page 132, bottom paragraph: for better clarity, the first sentence should read “Suppose the Input signal of Fig. 6.5 was a stable 1kHz clock frequency.”
Page 136: Program Example 6.6 caption is misleading. Replace with “Program Example 6.6: Using Timer 0 as a counter”
Page 139: the last paragraph should reference Fig. 2.11, not Fig. 2.10.
Errata
The last two lines of page 145 should read:
· the architecture of the 16F87XA family, of which the 16F873A is a member,
· the 16F87XA memory map and interrupt structure,
Page 163: replace ADCON0 with
ADCON1
Caption of Fig. 7.15 should read:
Figure 7.15
Block diagram
of Port A pin driver circuits. (a) ......
Page 168: bottom line, replace 125 ns with 250 ns.
Page 169: Caption of Fig. 7.19 should read: Figure 7.19 Oscillator traces from 16F873A devices. (a) RC oscillator, 800kHz nominal. (b) .....
Page 172: first line, replace "debugger" with "programmer"
Using the Futaba S3003 Servo
This servo is power hungry, as mentioned in the first paragraph of 9.6.1. That's why in Program Example 9.3 we ramp it to move. However experience with a number of builds has shown that the values used still leave the performance "on edge". If battery voltage is on the low side, and/or alkaline batteries are not in use, and/or the voltage regulator goes into over-current shut-down too enthusiastically, then there is a dip in the 5V line, and Brown-out reset is invoked (this is left enabled in this Program in the version on the book CD).
Errata
Section 9.5.3, 1st line of 2nd para: "L913D" should read "L293D"
Using the SRF05 Ultrasound Ranger
Program Example 9.7 was written for the SRF04 ultrasonic ranger. If used with
a SRF05 sensor, then it doesn't work, as there is a longer time delay between
pulse input, and echo pulse output. The
data sheet indicates
700us, though measurements have returned higher values (approaching 800us).
Therefore the 300us delay introduced in the program is inadequate. A simple
program change is to remove the 300us delay, and insert these two lines, causing
a wait until the echo pulse goes high:
btfss portc,6 ;wait until echo pulse goes high
goto $-1
The later lines
;add in blanked 3cms (this derived
experimentally)
addlw 3
can also be removed or the added value adjusted.
Errata
Page 267: 4th line: remove second "both" in this line.
Page 278: 3rd line from bottom: second "SDI" should read "SDO".
Page 294: Fig. 10.24: Label should read "Midpoint of Start bit".
Page 299: The key to Fig. 10.28 references
bits RCIF, RCIE twice. The correct reference is: For RCIF, RCIE, see Fig.
7.12.
Program Example 9.7 is referenced on page 329 of this chapter. Check comments about it under Chapter 9.
Errata
Page
313: The first
sentences should read "The input multiplexer, seen to the right of the diagram, has 5 channels for the
16F873A and ’F876A, and 8 for 16F874A and ’F877A. The inputs are shared with
five of the six Port A bits, and three of the eight Port E (for 16F874 and
’F877) bits."
Page 313: The last sentence in the second to
last paragraph should read: "Best practice is therefore to set the ADC clock frequency such that it has a
period equal to or just more than 1.6us."
Page 316: First
paragraph: all references to "PGFC" should be to "PCFG"
Page 324:
Reference is made in the last two lines to rounding errors, while in fact it is
truncation errors which are being forced in the data manipulation under
discussion. A better wording would be “This
depends on the rounding or truncation error introduced. The error in taking 1250
instead of 1250.048 is very small, …” See Section 11.4 of Reference 1.1 for a
discussion of rounding and truncation errors.
Chapter 12
Errata
Page 340, 4th line of 5th paragraph: should read "...which signals an
overflow of the two's complement 7-bit range..."
Page 342, Table 12.2: the two rotate left instructions should read rlcf,
and rlncf.
Page 352, Section 12.6.2: second paragraph: Replace the final sentence
with "The instructions push and pop allow the programmer
respectively to push the current Program Counter value onto the Stack, or
to simply discard the top of stack, adjusting the Stack Pointer in each case.
These are made available primarily to allow the user to set up and manage a
software stack".
Errata
Page 392, Section 14.2.6, 3rd paragraph: Extend first sentence to read:
"Data names must start with a letter or underscore".
Page 396, Section 14.4.1: third line should read: "TRISA
= 0b10000110; // initialise PORTA"
Page 406,
Table
14.4: caption should read “Example C18 general software library memory
functions”.
back to top
Section 19.8 is a very brief consideration of the issue of RTOS overheads. It is worth noting that the comments made apply primarily to small-scale programs, such as the ones we have considered in the book. For larger programs, it may be that these simple generalisations do not apply, i.e. that an RTOS-based program is inevitably longer than its sequentially-programmed equivalent. For example, for a program of 10-12 tasks, the code length may be actually shorter than its equivalent, written as a super-loop.
Errata
Page 485, bottom line: should be Table 19.2.
Page 487, Section 19.4.1, first paragraph, last line: labels should be
Count_Task1
and
Display_Task1
Page 487, Section 19.4.1, second paragraph, 4th line: should be Table
19.2.
Page 494, first line of Section 19.5.2: Replace sfc18sfa.lib with
sfc18sfm.lib
Page 497, Table 19.4: In left column OSECB( ) should be changed to
OSECBP( ). This change should also be made in the cell opposite, where the
reference to Table 18.2 should be to Table 19.2.
Page 500, second from last line: Reference should be to Section 8.6.5, not
18.6.5.
back to top
Appendix 3
Errata
Fig. A3.1: There are two R10's and two R17's in this diagram. A revised
circuit diagram is available on the Derbot
page.
Fig. A3.2: A pull-up resistor of value 4.7kW should be
shown, connected from pin 6 of the 16F873A to +5V.
Errata
Program Example 8.4 i)
In the
initialisation an attempt is made to write to the PR2 SFR, with the bank select
bits incorrectly set. This appears in the program section:
bcf status,rp0 ;select bank 0
;set up PWM
…
movlw D'249' ;sets
PWM period. (alternative values can be used)
movwf
pr2
The result of this is that the number D'249' is written to the T2CON register, which occupies the same location as PR2, in bank 0. This overwrites the setting previously placed in T2CON. In this case, D'249' = B'1111 1001. Checking the layout of T2CON (Fig 9.5 in book), we can see that, with bit 2 being 0, this turns Timer 2 off, and the PWM no longer functions.
To fix, set bit rp0 to 1 before writing to PR2! The simplest way to do this is to move that write up to where the TRIS registers are being accessed; these lie in Bank 1. The code section then appears:
bcf status,rp1
bsf status,rp0 ;select memory bank 1
movlw
B'00000000' ;set port A bits according to their function, 1=input, 0=output
movwf
trisa
…
movlw D'249' ;sets
PWM period. (alternative values can be used)
movwf
pr2
bcf status,rp0 ;select bank 0
;set up PWM
Etc
Program Example 8.4 ii)
The Delay1 subroutine was written for an 8MHz clock, but applied here with a
4MHz clock, without adjustment. In this program the delay introduced is not
critical, so this error is not significant. The subroutine should be corrected
if it is to be used in a context which is time critical. A correct version
can be seen in other programs, e.g.
Program Example 9.7.
Program Example 9.7
The I2C_send_stop subroutine has mysteriously
lost its last two lines, although these appear in other programs which use this
subroutine. Fortunately the effect is minimal, as program execution
proceeds on to the next subroutine, a short delay, and the program appears to
right itself. The subroutine, as shown here in full, should of course be
corrected if the program is to be used.
I2C_send_stop bsf status,rp0
bsf sspcon2,pen
;force stop bit.
btfss sspstat,p
;test for stop bit completion
goto $-1
bcf status,rp0
return
Program Example 11.3
Unfortunately the version for a slightly earlier Derbot has crept in. A
change of two bits in the TRISB setting is required, as shown:
;Initialise
...
movlw B'00110000'
movwf trisb
Program Example 16.2
The word "rom" should be removed from line 14. The program appears correctly
in the book.
