Computer Interfacing Book

	Introduction	xi
Part 1	Revision and Reference	1
1	Number systems	3
1.1	Direct conversion of binary numbers	3
1.1.1	Converting from denary to binary	4
1.1.2	Converting from binary to denary	4
1.2	Binary coded decimal	5
1.3	Hexadecimal numbers	5
1.4	Signed numbers	6
1.4.1	2's complement representation of negative numbers	7
1.4.2	Addition of signed binary numbers	8
1.5	Floating point numbers	8
1.5.1	Floating point conversion examples	9
1.5.2	Biased exponents	9
1.6	Representation of alphanumeric characters	10
1.7	Number system conversions	10
1.7.1	Convert all characters to upper case	10
1.7.2	Convert all characters to lower case	11
1.7.3	Convert ASCII 0 to 9 to 4-bit binary	11
1.7.4	Conversion of ASCII to hexadecimal	11
1.8	Questions	12
2	Electronic gates and registers	15
2.1	Logic gates	15
2.1.1	Gate: truth tables and symbols	15
2.1.2	Commercial logic gates	18
2.1.3	Examples of TTL and CMOS ICs	18
2.2	Address decoders	19
2.3	Three-state output devices	20
2.3.1	The three-state buffer	20
2.3.2	Static RAM input control	21
2.3.3	Octal three-state buffers	22
2.3.4	8-bit bi-directional, three-state buffer	23
2.4	Sequential logic	24
2.4.1	The D-type latch	24
2.4.2	Octal three-state buffer, register	25
2.5	Bus systems	25
2.6	Practical RAM exercise	27
3	An 8-bit microprocessor	29
3.1	Introduction of microprocessors	29
3.2	An 8-bit microprocessor system	30
3.2.1	System operation	30
3.2.2	The microprocessor unit (MPU)	30
3.2.3	Read only memory (ROM)	31
3.2.4	Random access memory (RAM)	32
3.2.5	Clock and reset circuits	32
3.2.6	Address bus	32
3.2.7	Data bus	32
3.2.8	The control bus	33
3.2.9	Address decoder	33
3.2.10	The stack	33
3.3	The Zilog Z80 CPU	34
3.3.1	General description	35
3.3.2	The status register	36
3.3.3	MPU timing diagram	38
3.3.4	Instructions and addressing modes	39
3.3.5	Addressing mode examples	39
3.3.6	The program	41
3.3.7	Interrupts	42
3.3.8	Short interrupt routine	45
Part 2	Theory and Programming	47
4	Types of microprocessor	49
4.1	Types of microprocessor	49
4.1.1	Aims of a system design	50
4.1.2	Speed of processing and data transfer	50
4.1.3	Cost of the system	51
4.1.4	Input/Output facilities	51
4.1.5	Physical size	51
4.2	MPU techniques	52
4.2.1	Pipelining	52
4.2.2	Cache memory	53
4.2.3	Overlapped register windows	54
4.2.4	MPU timing and control	55
4.3	Complex instruction set computer (CISC)	57
4.3.1	The Motorola 68000 MPU	57
4.4	Reduced instruction set computer (RISC)	59
4.4.1	The Motorola MC88100	59
4.5	Single chip microcontrollers	59
4.5.1	The Philips 83/87C752 (8XC752) microcontroller	60
5	Microprocessor applications	62
5.1	Control and instrumentation systems - the airflow meter	62
5.1.1	Hardware construction	63
5.1.2	Software development	64
5.2	Communication systems - digital signal processing	67
5.3	Commercial systems - the desktop computer	70
5.3.1	The system	70
6	Software design	73
6.1	Software development	73
6.2	Top down design	74
6.3	Structured programming	75
6.3.1	Jackson Structured Programming (JSP)	75
6.4	Pseudo code	77
6.4.1	Sequence	78
6.4.2	Selection	78
6.4.3	Iteration	79
6.5	Flowcharts	79
7	Programming in C	81
7.1	An introduction to C	81
7.2	Eight steps to programming in C	82
7.3	Writing C programs	84
7.4	Debugging the program	84
7.4.1	Typical errors	85
7.5	Program examples and exercises	85
7.5.1	Exercise - output of strings, printf()	85
7.5.2	Exercise - print the bytes reserved for variables	86
7.5.3	Exercise - number converter	87
7.5.4	Exercise - clear the screen	88
7.5.5	Exercise - the for loop	88
7.5.6	Exercise - square of numbers	89
7.5.7	Exercise - store data in an array	89
7.5.8	Exercise - modifications to Exercise 7.5.7	90
7.5.9	Exercise - store data on disc	90
7.5.10	Exercise - testing Exercise 7.5.9	91
7.5.11	Exercise - load data from a disc file	91
7.5.12	Exercise - alternative load data from a disc file	94
7.5.13	Exercise - temperature conversion	96
7.5.14	Exercise - writing functions	98
7.6	Selected answers	98
Part 3	Interfacing Exercises	99
8	Serial interfacing	101
8.1	Serial data transmission	101
8.2	Serial interfacing hardware	103
8.3	Serial data exercises	103
8.3.1	Exercise - serial loop-back test	104
8.3.2	Exercise - investigation of comm. port signals	106
8.3.3	Exercise - communication between two computers	106
8.3.4	Exercise - text transmission	107
8.4	Questions	107
9	Parallel interfacing	108
9.1	The Intel 82C55A PPI	108
9.1.1	PPI mode 0 (basic input/output)	109
9.1.2	Exercise - number output mode 0	110
9.1.3	Exercise - input test mode 0	111
9.1.4	PPI mode 1, strobed input/output	114
9.1.5	Exercise - PPI mode 1, output test	114
9.1.6	Exercise - mode 1 input test	117
9.2	Stepper motor exercises	118
9.2.1	Exercise - stepper motor control	118
9.2.2	Exercise - three-speed motor control	122
9.2.3	Exercise - control of two stepper motors	122
10	Digital to analogue parallel interfacing	123
10.1	Digital to analogue conversion	123
10.2	D to A exercise	125
10.2.1	Exercise - D to A test	125
10.3	Waveform generator	127
10.3.1	Exercise - waveform generator	127
10.3.2	Exercise - complete the waveform generator	129
10.4	Questions	130
11	Analogue to digital parallel interfacing	131
11.1	Analogue to digital converters	131
11.1.1	The counter ramp A to D converter	131
11.1.2	Flash A to D converter	132
11.2	A to D exercises	134
11.2.1	Exercise - ADC test	134
11.2.2	Exercise - voltmeter	138
11.2.3	Exercise - two-range voltmeter	138
11.3	Questions	139
12	The parallel printer port	140
12.1	The parallel printer port	140
12.2	Output/Input exercises	140
12.2.1	Exercise - output data via the printer port	140
12.2.2	Exercise - input/output data via the printer port	141
12.3	Stepper motor exercises	145
12.3.1	Exercise - stepper motor; two speeds in each direction	145
12.3.2	Exercise - stepper motor; three speeds in each direction	148
12.3.3	Exercise - two motors, two speeds	148
12.4	Waveform generator exercises	148
12.4.1	Exercise - waveform generator	148
12.4.2	Exercise - complete the waveform generator	150
12.5	Voltmeter exercises	150
12.5.1	Exercise - ADC	150
12.5.2	Exercise - voltmeter	153
12.5.3	Exercise - two-range voltmeter	153
13	Additional exercises	155
13.1	Frequency counter theory	155
13.1.1	The Schmitt trigger	156
13.1.2	The binary counter	156
13.2	Frequency counter exercises	159
13.2.1	Exercise - basic counter	159
13.2.2	Exercise - four-range counter	161
13.2.3	Exercise - improve the accuracy to +/-1 Hz	161
13.2.4	Exercise - auto calibration	163
13.2.5	Exercise - counter input circuit	163
13.3	Serial data communication	164
13.4	Stepper motor control via serial link	165
13.4.1	Exercise - control of two stepper motors via a 4-conductor, serial link	165
13.4.2	Exercise - use two conductors plus ground to to control two stepper motors	169
13.4.3	Exercise - serial control of three stepper motors	169
14	Equipment and testing	172
14.1	Test equipment	172
14.2	Hardware problems	173
14.3	Testing the PPI ports	173
14.3.1	Testing the PPI port for correct outputs	174
14.3.2	Testing the PPI port for correct inputs	175
14.4	Testing the parallel printer port	177
14.4.1	Output test software	178
14.4.2	Input test software	178
14.5	Construction of LED and switch boxes	178
14.5.1	The LED box	179
14.5.2	The switch box	180
14.5.3	Economy LED/switch box	180
14.6	Stepper motor driver	182
14.7	Software problems	182
	Bibliography	185
	Index	187