Transcript
Experiment-20 Building an 8086 Based Temperature Meter on Breadboards Read every step of a task and work accordingly. When you finish a step, put Tick Mark ( ) on the step using a wood pencil. Ask Lab Teacher for Help. Task-20.1
Introduction
The best way to learn architecture and programming of 8086 microprocessor is to design and develop a small system that can possibly be accommodated on breadboards. To accomplish this purpose, we have presented in this experiment, the design and development procedures of an 8086 based ‘Temperature Meter (Fig-20.1-20.3).’ The control program of the meter has been developed and tested using MicroTalk-8086 Trainer of Fig-20.2. Finally, the program codes and the data are stored into the EPROMs (U6, U7 of Fig-P1.1) using commercial ROM programmer – TOP2005.
Figure-20.1: Components Layout
Figure-20.2: Developing by MicroTalk-8086 tempM
U11 8255
U1 8284
U7 27C256 (Ubank)
Y1
U6 AD0832
U12 27C256 (MPDEC)
DP0 DP2 DP2 DP3 U8 27C256 (Lbank) U2 8086
+5V Power Supply
U9 62256 (Ubank) U3 74LS373
U10 62256 (Lbank)
U4 74LS373
U5 74LS373
Figure-20.3: Expanded View of Components on Breadboard
Heat
NTC +5 TS V
Simplified Hardware Block Diagram U6: ADC0832
DO Ch1 DI R2 TOU VDT Ch0 CK 5k T A (22.8 C, 1.64V) CS/ 6 B (25.0 C, 1.80V) 0V Response of TS Temp Sensor Serial ADC
+5V R1 10k
U11: 8255
PC4 PC2 PC1
20mS
U2: 8086 NMI
CS/ B
B
B
PC0
B RAM IO Controller U9, U10
MPU
U11: 8255
1/10
Task-20.2
B
PA7-PA0 8 p,…,a
PB3-PB0 B ROM U7, U8 IO Controller
DP0 DP1 DP2 DP3
cc0 cc1 cc2 cc3
CC7SDD
Figure-20.4: Simplified Hardware Block Diagram for 8086 Based Temperature Meter
87
za
Brief Functional Description: The sensor NTC (Negative Temperature Co-efficient) produces a DC signal (VDT = Voltage as DC form for temperature T), which is proportional to ambient temperature, T. VDT is digitized by the serial ADC (U6) and then reaches to the CPU (U2) as V HT ( Voltage as Hex output of ADC for temperature T) via interface controller U11. The CPU computes the gain and offset of the sensor (broadly speaking the input subsystem) from its response curve (Fig-20.5) and applies them on VHT to recover the original decimal value of temperature (say, 25.300C). The CPU converts the BCD digits of the temperature into cc-codes (common cathode codes), which are then displayed onto multiplexed type CC7SDD devices. Temperature Sensor (NTC): It is a semiconductor type sensor with ‘Negative Temperature Coefficient (NTC)’ characteristics. As the ambient temperature increases, the resistance of the device decreases. A simple NTC-R2 network senses the environment temperature and produces a DC voltage VDT. VDT increases as the temperature increases. The sensor is linear and follows the response curve of Fig-P1.4 with definite gain and offset, which are computed from the measured values of the points A (T1, VDT1) = A(22.8 0C, 1.64V) and B(T2, VDT2) = B(25.0 0C, 1.80V). The magnitude of the unknown temperature C (T, VDT) is found by applying gain and offset on VDT. V
Actual Response
B ( 25 C ,1 . 80 V )
C ( T , V DT ) A ( 22 . 8 C ,1 . 64 V ) gain
T T1
T
T2
Offset 645cxd
Figure-20.5: Response Curve of Temperature Sensor
VDT is placed to the serial ADC (U6) via Channel-0 (Ch0). The 8-bit digital signal VHT goes to the microprocessor via interface controller. Here, the temperature T assumes (i) VDT in the decimal domain, and (ii) VHT in the hexadecimal (binary) domain. Both VDT and VHT refer to the same quantity, which is T 0C. The CPU calibrates VHT using the response curve of Fig-P20.5 and transforms VHT back to the decimal value. The BCD digits are converted into their equivalent cc-codes, which are displayed on the cc-type multiplexed display unit (DP0 – DP3) via 8255 IO controller. Response of the temperature sensor refers to (i) the measurement of DC voltages (VDT1, VDT2) of the sensor at two different known temperatures (T1, T2), and (ii) finding the equation of T in terms of the known points A(T1, VDT1) and B(T2, VDT2). T1 and T2 could be measured by a commercial thermometer. VDT1 and VDT2 could also be measured by a DVM. The response equation for T using Fig-P1.4 is:
VDT 2 VDT1 VDT VDT 2 T 2 T1 T VDT 2
T m *VDT c
T
T 2 T1 T 2 T1 * VTD (T 2 V DT 2 * ) VDT 2 VDT1 V DT 2 VDT1
……………………………………………(1)
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In Eqn. 1, we have VDT. So, T is in the decimal domain. But after digitization, the CPU has measured the binary value of VDT, which is VHT. Now, we need to transform T from decimal domain into binary (hexadecimal) domain. To do it, we must figure out appropriate multiplication/division factor in the following way: If input analog signal to ADC is: 5V If input analog signal to ADC is: VDT Therefore, VDT = (VHT*5)/255
Output of ADC is 1111 1111B = 255 Output of ADC is = (255/5) * VDT = VHT
Now, we can write the following equation for T in the binary domain.
VHT * 5 c 255 T m *VHT * 0.0196 c
T m*
; m, (5/255) and c must be in their binary (Hex) equivalents
From the given values of A (T1, VDT1) = A(22.80C,1.64V) and B(T2, VDT2) = B(250C, 1.80V), we may calculate gain (m) and offset (c) as – m
25.0 22.8 2.2 13.75 1.80 1.64 0.16
c 25.0 1.80 *13.75 25.00 24.75 0.25 T m *VHT * 0.0196 c T 13 .75 *VHT * 0.0196 0.25 T 0.2695 *VHT 0.2500 T *10 4 2695 *VHT 2500 T *10 4 0 A87 h *VHT 09 C 4h
…………………..……………………………(2)
Serial Analog-to-Digital Converter (U6, ADC0832): The ADC has two single-ended channels – Ch0 and Ch1. The temperature signal is acquired by Ch0. The full scale value of the ADC is +5V, which means that the ADC will produce an output signal of 1111 1111b (255) when the input analog signal is +5V. It is a serial ADC and hence the data bits come out bit-by-bit using the DOpin with MS-bit first. The command bits for channel selection enter into the chip bit-by-bit using its DI-pin. The clock pulses needed for clocking out the data bits and clocking in the command bits are artificially generated and are passed to the chip over the CK-pin. Chip select pin (CS/) allows putting more than ADC chips in a system and also brings the ADC into conversion mode. The PC0, PC1, PC2 and PC3 pins of the 8255(U11) controller handles the CS/, CK, DI and DO signals of the ADC. For proper operation of the DO-pin, it requires to be terminated to +5V by a 10k resistor. The Programming Table, Timing Diagram and the Data Read Flow Chart of ADC0832 are given in Table-P1.1, Fig-P1.17 and P1.18 respectively. IO Controller (U11, 8255): The serial ADC chip communicates with the CPU via Port-(C (PC4, PC2 – PC0) of the 8255 controller. The display unit is also interfaced to the microprocessor bus through the IO lines of 8255.
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CC7SDD (Multiplexed Display Unit, DP0-DP3): In a non-multiplexed display system, every 7segment display device has separate 9-lines to drive its segments and cc-point. Thus, to drive a 4digit display unit, we would require 9x4 = 36 lines. In a multiplexed display system, the similar segment pins of all the display devices are connected together and is driven by just eight lines (instead of 32 lines for 4-digit display). The cc-pins are driven by separate lines. Thus, to drive a 4-digit display unit, we need only 8+4 = 12 lines. The display unit of Fig-P1.3 is an example of a multiplexed display system. In a multiplexed display system, the 8-bit cc-coded data (say, 4F for 3) for a character appears to the segment pins of all the display devices at the same time via Port-A (PAR) register. If we want see this character to be visible only at DP0-position, we need to apply 0V (LL) at cc0-pin and +5V (LH) to the cc-pins of the DP1 and DP3 display devices. Similarly, to see a character A at DP1position, we assert cc-code of A on PAR, LL at cc1-pin and LH at cc0, cc2 and cc3 pins. In a multiplexed display system, we need to continuously refresh the display unit with the respective character data for the display devices. Otherwise, the display unit will remain frozen to a single digit at one of the four display positions. Y1 6 MHz
U1: 8284
U2: 8086 (MPU) 1/3Y1
CLK RST RDY
K1 +5V 0V
RST/ RDY
+5V
U11: 8255
B
B
MN-MX/
PAR (3600) CR
DP3
Detailed Hardware Block Diagram DP0
Task-20.3
8
0
p,…,a cc0 cc2cc3
C
cc0-cc3
(3606)
CLK
PB0-PB3 (3602) U3-U5 : 3xLS373
T Sensor tempM
DI CLK CS/ ADC
PC2 PC1 PC0 PIO
CSU10/ CSU9/
y0y1 y2 y3 y7
4 CS11/ CSU7/ CSU8/
Even Bank
Ch0
B Even Bank
DO
B
ODD Bank
TOUT
0V
VDT
BHE/ A16-A19 A0-A15
ODD Bank
Ch1 R2 5k6
Q Q Q
U7-U8 U9 - U10
B
B (3604) PC4
Decoder
+5V
CS10/
A16-19 M-IO/ BHE/ A0
R1 10k
CK D D D
ALE BHE/-S7 A16/S3-A19/S6 AD0-AD15
U11: 8255
A3 A2 A1 A0
Heat
+5V
U12: 27C256
U6 : ADC0832
NTC
CSU7-10/ ROM RAM 27C256 62256 Memory
Figure-20.6: Detailed Hardware Block Diagram for 8086 Based Temperature Meter
U2 (8086 Microprocessor): The microprocessor has been configured in minimum mode by strapping its MN-MX/ pin to +5V. The 8086 uses multiplexed bus for the composite signals AD0AD15, A16/S3-A19/S6 and BHE//S7. U3-U5 (74LS373 Latch): These latches hold the A0-A15, A16-A19 and BHE/ signals from their respective composite signals of AD0-AD15, A16/S3-A19/S6 and BHE/-S7 at the beginning of a machine cycle.
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U6 (ADC0832 Serial Analog-to-Digital Converter): It acquires signal from temperature sensor, digitizes it and then sends it to the CPU via 8255. Channel selection command and the necessary clock signals are artificially generated by the IO lines of the 8255. U7-U8 (27C256 EPROM): U7 and U8 are respectively the ODD and EVN bank of ROM space. U9-U10 (62256 RAM): U9 and U10 are respectively the ODD and EVN bank of RAM space. U11 (8255 PIO Controller): It has interfaced the serial ADC and the display unit with the MPU. U12 (27C256 Memory/Port Decoder): It selects one memory/port chips out-of-many. U1 (8284 Clock Chip): It accepts (i) RST/-signal, (ii) crystal, and (iii) ready signal from outside and then produces (i) RST signal, (ii) clock and (iii) ready signal for the MPU. Parts List Sn
Type No.
Function
Quantity
1 2 2 3 4 5 6 7
Circuit Designation U1 (Fig-P1.11) U2 U3-U5 U6 U7-U8 U9-U10 U11 DP0-DP3
8284 8086 74LS373 ADC0832 27C256 62256 8255 CC-type
8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30
U12 R1-R2 C14-C15 K1 T1 D1-D2 C15 C1-C13 Q1 Y1 R3 LED1 Electronic Cutter Nose Pliers Screw Driver NTC R4 -
27C256 4.7 k 100uF/16V Push 220/6-0-6 IN4004 1000uF/25V 0.1uF/63V 7805 6MHz 2.2K Red -
Clock Chip Microprocessor Data Latch Serial ADC EPROM RAM PIO Controller 7-Segment Display Devices EPROM PCB Mountable Switch 600mA Transformer Rectifying Diode Capacitor Ac Decoupling Capacitor +5V Regulator Crystal Resistor Light Emitting Diode Shrinkable Tubing As per Sample As per sample As per Sample Good Quality Breadboards Right Size Jumper Wires Temperature Sensor Resistor Bakelite Board 2-Pin AC Plug for 220V Ac Wire
5.6K` 10” x 6” -
91
Shop
1 1 3 1 2 2 1 4
Approx Unit Price Tk 200/Tk 220/Tk 40/Tk 110/Tk 150/Tk 150/Tk 250/Tk 15/-
1 2 2 1 1 2 1 13 1 1 1 1 1 ft 1 1 1 2 250 gm 1 1 1 1 2 yrds
Tk 150/Tk 1/Tk 1/Tk 5/Tk 80/Tk 3/Tk 10/Tk 0.25/Tk 15/Tk 15/Tk 1/Tk 2/Tk 20/Tk 330/Tk 150/Tk 20/Tk 250/Tk 300/Tk 50/Tk 1/Tk 80/Tk 20/Tk 10/-
Do Do Do Do Do Do Do Do Do Do Do Do Do Do Do Do Do Do/Dolai Khal Stadium/Patuatully Do Kawran Bazar Electric Shop do
Stadium/Patuatully Do Do Do Do Do Do Do
Task-20.4 20.4.1 (1)
(2) (3) (4) (5)
Hardware Building Procedures
A: +5V Supply Subsystem
Check that you have the following parts placed on the breadboard as per layout of Fig-20.1, 20.3 1. Transformer : T1 220/9-0-9 2. Diode (2) : D1, D2 (IN4003) 3. Capacitor : C16 1000uF/25V 4. +5V Regulator : Q1 (7805) 5. Capacitor : C14 100uF/16V 6. Capacitor : C13 (0.1uF = 104) 7. LED1 : Red One 8. Resistor : R3 2.2k 9. Jumper Wires : as needed Connect the components together using jumper wires as per diagram of Fig-20.7. Apply 220V AC supply Check that LED1 glows. Measure +5V with a DVM. Disconnect 220V supply. 734x 7805 D1
9 0V
220V
1
2
D2
3
+5
C14 100uF /16V
+ 9
Q1
R3 2.2k
C13 0.1uF
C16 1000uF/25V
LED1 0V
Figure-20.7: Schematic of +5V Supply
20.4.2 (1)
(2) (3)
Temp Signal Acquisition Subsystem (Fig-20.8) Check that you have the following parts placed on the breadboard as per layout of Fig-20.1-20.3. 1. Temp Sensor : NTC 2. ADC : U6 ADC0832 3. Resistor : R2 5.6k 4. Resistor : R1 10k 5. Interface Controller : U11 8255 8. Jumper Wires : as needed Place the components on the breadboard as per circuit diagram of Fig-20.8. Complete only those lines of the following diagram, which have source and destination signals. For example – Pin-6 of U6 has the source signal (DO) and destination signal (PC4). So, these two points (U6-6 and U11-13) must be connected together. Similarly connect other signal lines. NTC +5V
R2 5k6 0V
NTC
TOUT
+5V R1 = 10k
U6: ADC0832 NC VDT +5V 0V
3 2
6
Ch1
Ch0 8 Vcc 4 GND
PC4 17 PC2 16 PC1 15 PC0
Pin Signals Pin Numbers Line Signals
(4) (5) (6) (7) (8)
U11: 8255 13
DO 5 DI 7 CK 1 CS/
CS/ B
NC = No connection za1
Figure-20.8: Schematic of ADC Subsystem Apply 220V AC supply. Measure VTD signal with a DVM and record it in your Project Khata. Use a gas lighter and gently heat up the NTC sensor. Measure VTD and record it. Check that the value has increased compared to the previous value. Disconnect the 220V supply.
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20.4.3 (1)
Multiplexed Display Subsystem (CC7SDD) Check that you have the following parts placed on the breadboard as per circuit of Fig-20.9. 1. CC-type 7SDD (4) : DP0-DP3 CC-type 2. Jumper Wires : as needed Complete only those lines of the following diagram, which have source and destination signals.
(2)
Figure-20.9: Schematic Diagram for cc-type Multiplexed CC7SDD
20.4.4 (1)
EPROM Subsystem Check that you have the following parts placed on the breadboard as per circuit of Fig-20.10. 1. EPROM (2) : U7-U8 27C256 2. Jumper Wires : as needed Complete only those lines of the following diagram, which have source and destination signals.
(2)
U7 Vcc RD/ CSODDROM A15 A14 A13 A12 A11 A10 A9 A8 A7 A6 A5 A4 A3 A2 A1
1 22 20 27 26 2 23 21 24 25 3 4 5 6 7 8 9 10
27C256
U8
VPP OE CE A14 A13 A12 A11 A10 A9 A8 A7 A6 A5 A4 A3 A2 A1 A0
VCC GND O7 O6 O5 O4 O3 O2 O1 O0
28 14 19 18 17 16 15 13 12 11
Vcc GND AD15 AD14 AD13 AD12 AD11 AD10 AD9 AD8
Vcc RD/ CSEVNROM
1 22 20
A15 A14 A13 A12 A11 A10 A9 A8 A7 A6 A5 A4 A3 A2 A1
27 26 2 23 21 24 25 3 4 5 6 7 8 9 10
27C256
VPP OE CE A14 A13 A12 A11 A10 A9 A8 A7 A6 A5 A4 A3 A2 A1 A0
P1.9
Figure-20.10: Schematic Diagram of EPROM Subsystem
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VCC GND O7 O6 O5 O4 O3 O2 O1 O0
28 14
Vcc GND
19 18 17 16 15 13 12 11
AD7 AD6 AD5 AD4 AD3 AD2 AD1 AD0
20.4.5 (1)
RAM Subsystem Check that you have the following parts placed on the breadboard as per circuit of Fig-20.11. 1. RAM (2) : U9-U10 62256 2. Jumper Wires : as needed Complete only those lines of the following diagram, which have source and destination signals. Connect A1-A14, AD0-AD15 line signals with corresponding line signals of U7-U8 of Fig-20.10.
(2) (3)
WR/ RD/ CSODDRAM
27 22 20
A15 A14 A13 A12 A11 A10 A9 A8 A7 A6 A5 A4 A3 A2 A1
WR/ RD/ CSEVNRAM
WE OE CE
1 26 2 23 21 24 25 3 4 5 6 7 8 9 10
A14 A13 A12 A11 A10 A9 A8 A7 A6 A5 A4 A3 A2 A1 A0
VCC GND
O7 O6 O5 O4 O3 O2 O1 O0
U9
19 18 17 16 15 13 12 11
A15 A14 A13 A12 A11 A10 A9 A8 A7 A6 A5 A4 A3 A2 A1
Vcc GND
28 14
27 22 20
AD15 AD14 AD13 AD12 AD11 AD10 AD9 AD8
1 26 2 23 21 24 25 3 4 5 6 7 8 9 10
62256
WE OE CE A14 A13 A12 A11 A10 A9 A8 A7 A6 A5 A4 A3 A2 A1 A0
VCC GND
O7 O6 O5 O4 O3 O2 O1 O0
U10
28 14
Vcc GND
19 18 17 16 15 13 12 11
AD7 AD6 AD5 AD4 AD3 AD2 AD1 AD0
62256
P1.10
Figure-20.11: Schematic Diagram of RAM Subsystem
Y1
6 MHz
+5V R4 4k7 K1
16
VCC
11
X2
(2)
Clock Subsystem Check that you have the following parts placed on the breadboard as per circuit of Fig-20.12. 1. Clock Chip : U1 (8284) 2. Crystal : Y1 (6 MHz or close) 3. Resistor : R4 (4.7k) 4. Capacitor : C15 (100uF/16V) 5. Switch : K1 (ON/OFF (not Latch) 6. Jumper Wires : as needed Complete only those lines of the following diagram, which have source and destination signals.
17
(1)
X1
20.4.6
CLK READY RESET
RES
100uF +
PCLK
C15
+5V
6 3 7 14 1 15 13 4
RDY 2 AEN1 AEN2 EFI CSY NC ASY NC F/C RDY 1 U1
PCLK RESET OSC
OSC GND VCC
8 5 10
CLK 1/3Y1 READY
2 12 9 18
GND +5V
8284
1/6Y1 RESET Y1=6 MHz
P1.11
Figure-20.12: Schematic Diagram of Clock Subsystem
94
+5V CLK READY RESET
33 19 22 21
MIN-MX CLK READY RESET
1
MIN86
GND
20
U2
GND
(2) (3) (4) (5) (6) (7)
CPU Subsystem Check that you have the following parts placed on the breadboard as per layout of Fig-20.13. 1. Microprocessor : U2 (8086) 2. Data Latch (3) : U3-U5 (3x74LS373) 3. Jumper Wires : as needed Complete only those lines of the following diagram, which have source and destination signals. Connect line signals REDAY, CLK and RESET with corresponding line signals of U1 (8284). Connect line signals AD0-AD7 with corresponding line signals of U8 (27C256). Connect line signals AD8-AD15 with corresponding line signals of U7 (27C256). Connect line signals A1-A15 with the corresponding line signals of U7 (27C256). Connect line signals RD/ and WR/ with the corresponding line signals of U9 (62256).
40
(1)
VCC
20.4.7
INTA M-IO RD WR DT-R DEN ALE
24 28 32 29 27 26 25
M-IO/ RD/ WR/
U5 GND
BHE/S7 A19/S6 A18/S5 A17/S4 A16/S3
1 18 17 14 13 8 7 4 3
34 35 36 37 38
OE
LE
D7 D6 D5 D4 D3 D2 D1 D0
Q7 Q6 Q5 Q4 Q3 Q2 Q1 Q0
U4 1
23 31 30
TEST
AD15 AD14 AD13 AD12 AD11 AD10 AD9 AD8
39 2 3 4 5 6 7 8
AD15 AD14 AD13 AD12 AD11 AD10 AD9 AD8
18 17 14 13 8 7 4 3
HOLD HLDA
17 18
NMI INTR
AD7 AD6 AD5 AD4 AD3 AD2 AD1 AD0
9 10 11 12 13 14 15 16
AD7 AD6 AD5 AD4 AD3 AD2 AD1 AD0
18 17 14 13 8 7 4 3
LE
D7 D6 D5 D4 D3 D2 D1 D0
Q7 Q6 Q5 Q4 Q3 Q2 Q1 Q0
19 16 15 12 9 6 5 2
BHE/ A19 A18 A17 A16
11 19 16 15 12 9 6 5 2
A15 A14 A13 A12 A11 A10 A9A3 A8
74LS373
OE
LE
D7 D6 D5 D4 D3 D2 D1 D0
Q7 Q6 Q5 Q4 Q3 Q2 Q1 Q0
Figure-20.13: Schematic Diagram of CPU Subsystem
95
11
74LS373
OE
U3 1
74LS373
11 19 16 15 12 9 6 5 2
A7 A6 A5 A4 A3 A2 A1 A0
20.4.8 (1)
Memory/Port Decoding Subsystem Check that you have the following parts placed on the breadboard as per layout of Fig-20.14. 1. EPROM : U12 (27C256) 2. Jumper Wires : as needed Complete only those lines of the following diagram, which have source and destination signals. Connect line signals A0, A12-A16, BHE/ with corresponding line signals of U3-U5 (74LS373). Connect line signals M-IO/ with corresponding line signal of U2 (8086). Connect line signals CSEVNRAM, CSODDRAM, CSEVNROM, CSODDROM with corresponding line signals of U7-U8(27C256) and U9-U10(62256). Connect line signals CSPIO with the corresponding line signal of U11 (8255).
(2) (3) (4) (5) (6)
U12
`
VCC
Vcc GND
1 20 22 27 26 2 23 21 24 25 3 4 5 6 7 8 9 10
A19 A18 A17 A16 A15 A14 A13 A12 M-IO/ BHE/ A0
27C256
Vpp CE OE A14 A13 A12 A11 A10 A9 A8 A7 A6 A5 A4 A3 A2 A1 A0
GND VCC
O7 O6 O5 O4 O3 O2 O1 O0
GND Vcc
14 28
3000 - 3FFE
19 18 17 16 15 13 12 11
F0001 F0000 00000 00000
-
FFFFF FFFFE 0FFFF 0FFFE
: : : :
ODD EVN ODD EVN
ROM ROM RAM RAM
CSPIO NC NC NC CSODDROM CSEVNROM CSODDRAM CSEVNRAM
Figure-20.14: Schematic Diagram of Memory/Port Decoder
20.4.9 (1) (2) (3) (4)
PIO Interface Subsystem Check that you have the following part placed on the breadboard as per layout of Fig-20.15 1. PIO Interface Controller : U11 8255 Complete only those lines of the following diagram, which have source and destination signals. Connect line signals AD0-AD7, RESET, RD/ and WR/ with corresponding line signals of U2 (8086). Connect line signals A1, A2 with corresponding line signal of U3 (74LS373). U11 AD0 AD1 AD2 AD3 AD4 AD5 AD6 AD7
34 33 32 31 30 29 28 27
A1 A2
9 8
RESET RD/ WR/ CS8255
35 5 36 6
Vcc GND
26 7
Port Address PAR:3600h PBR: 3602h
8255
D0 D1 D2 D3 D4 D5 D6 D7
PB7 PB6 PB5 PB4 PB3 PB2 PB1 PB0
A0 A1
PA7 PA6 PA5 PA4 PA3 PA2 PA1 PA0
RESET RD WR CS VCC GND
PC7 PC6 PC5 PC4 PC3 PC2 PC1 PC0
25 24 23 22 21 20 19 18 37 38 39 40 1 2 3 4 10 11 12 13 17 16 15 14
NC NC NC NC NC PB2 PB1 PB0 PA7 PA6 PA5 PA4 PA3 PA2 PA1 PA0 PC7 PC6 PC5 PC4 NC NC NC NC
PCR: 3604h CR: 3606h
Figure-20.15: Schematic Diagram of PIO Subsystem
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T ask-20.5 Control Program Development Procedures Data Structure for the
F0000
BAS
DSM (RAM)
BAE
ESM (RAM)
BAD BAC MBA
Empty Space
Stack Grows
07000 06FFF TS Samples S0-S7 05010 05009 05000 04FFF 04003 04002 04001 04000 03FFF 03012 03011 03010 03002 03001 03000 02FFF 01000 00FFF 00000
Digit Vs CC-codes
L1: Initialize Stack
L2: ACQCH0
T5
Initialize Others as needed Acquire Temp Signal save in ah
L3:
T4
BINTEMP
Compute Temp As 16-bit Binary
L4: CCTEMP
DP3 DP2 T3 DP1 DP0
BCDTEMP
CCTEMP BCDTEMP
BINTEMP For testing Program
MB NB LB
Compute Temp As 4-digit BCD
L5:
L6:
T2
CCX7SDD
MS NB T1 LB CSM (RAM)
Compute Temp as 4-byte CC-code Show Temp on CC7SDD
L6A: 32 times refresh?
N
Y
IVT[02h]
L7: xx
xx
Figure-20.16 : Data Structure for Control Program
20.5.3
nop
L1A:
LUT
TOS
09000 Filled up 08FFF 08FFE 08FFD 08FFC
Flow Chart
START:
SSM (RAM)
FFFF0 jmp F0000h
20.5.2
CSM (EPROM) Control Program
FFFFF
Startup FFFF:0000
20.5.1
Figure-20.17: Flow Chart for Control Program
Develop Assembly Codes in the Form of Subroutines for the Control Program for the Temperature Meter using MicroTalk-8086 of Fig-20.2
;============================================================================= ; Program name : …\MTK8086\temp86.asm ORG 1000H ASSUME cs:MYCODE START: L1:
L1A:
nop ;-- stcak init-------------mov ax, 0000h mov ss. ax mov sp, 9000h ;-- init DSM and offset pointer— mov ds, ax mov bx, 3000h ;---------------------------call INIT ; initialize others as needed
L2:
call
ACQCH0
; read Temp and keep it in ah-register = VTH
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L3:
;-- compute Temp in Binary and save in locations 03000, 03001, 03002 ; by evaluating expression : T*104 = 0A87h* VTH + 09C4h call
BINTEMP
; 24-bit result in DSM
L4:
;-- convert BINTEMP into BCDTEMP and save in 03010, 03011, 03012 call BIN2BCD ; active result in <03010, 03011> =
=
L5:
;-- convert BCDTEMP into CCTEMP and save in 04000 – 04003 call BCD2CC ; (04000) = cc_p, (04001) = cc_q, (04002) = cc_r, (04003) = cc_s
L6: L6A:
;-- send CCTEMP onto CC7DD via 8255---------------------------mov cl, 20h ; refresh display for 32 times call CCX7SDD dec cl jnz L6A
L7:
;-- again acquire temperature----jmp L2 ;--------------------------------------------------------------------------------------------;Assembly Codes for Subroutines INIT: ;-- init Lookup Table for Digit Vs CC-cods in ESM--mov ax, 0000h mov es, ax mov di, 5000h mov mov mov mov mov
WORD PTR es:[di], 063FH WORD PTR es:[di+02h], 4F5Bh WORD PTR es:[di+04h], 6D66h WORD PTR es:[di], 077DH WORD PTR es:[di+02h], 6F7Fh
; cc-codes for 0, 1 ; cc-codes for 2, 3 ; cc-codes for 4, 5 ; cc-codes for 6, 7 ; cc-codes for 8, 9
;-- init 8255----------mov al, 84h ; PAR, PBR, PC0-PC3 output, PC4-PC7 input mov dx, 3606h ; address of Control Register out dx, al ;-------------------------ret ;------------------------------------------------------------------------------------------------------ACQCH0: ; acquire Temp Sensor signal (VTD) as binary (VTH) and save in ah-register ; copy codes from Section-1.46 ret ;-------------------------------------------------------------------------------------------------------BINTEMP: ;--- Evaluate T*104 = 0A87h* VTH + 09C4h = 0A87h* ah + 09C4h ; input via ah-register ; output BINTEMP via locations (03002) = MB-Byte, (03001) = NS-Byte, (03000) = LS-Byte ;-- compute 0A87h * VTH ; VTH in ah-register mov al, ah mov ah, 00h mov bx, 0A87h mul bx ; result in = dh, dl, ah, al = 00, dl, ah, al = 24-bit active ;----compute + 0009C4h add al, 0C4h adc ah, 09h adc dl, 0Ch adc dh, 00h ; 32-bit BINTEMP in = 00 dl, ah, al = 24-bit active ;-------------------mov WORD PTR ds:[bx], ax
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mov BYTE PTR ds:[bx+02h], dl ;BINTEMP via (03000)=LB, (03001)=NB, (03002)=MB ;-------------------ret ;---------------------------------------------------------------------------------------------BIN2BCD: ; converting 24-bit BINTEMP into 6-digit BCDTEMP ; input via 03000)=LB, (03001)=NB, (03002)=MB ; output via (03010)=LB, (03011)=NB, (03012)=MB mov cl, 18h ; size of input 24-bit data mov dl, 00h mov bx, 0000h ; IPBCD = Initial Partial BCD = AGNC: ;-- catch carry, evaluate IPBCDx02 + c and update IPBCD ror BYTE PTR ds:[bx], 01h ror BYTE PTR ds:[bx+01h], 01h ror BYTE PTR ds:[bx+02h], 01h ;-----call EVBCDHR ; Evalute BCD by Horner Rule ;-----dec cl jnz AGNC ; again catctch next carry ;-----mov BYTE PTR ds:[bx+12h], dl mov WORD PTR ds:[bx+10h], bx ; BCDTEMP via (03010)=LB, (03011)=NB, (03012)=MB ;----ret ;--------------------------------------------------EVBCDHR: ; Evaluate BCD using Horner Rule ; Evaluating IPBCD * 02 + Cx = 23 to 0 mov al, bl add al, al daa mov bl, al ;-----mov al, bh adc al, al daa mov bh, al ;-----mov al, dl adc al, al daa mov dl, al ;------ret ;---------------------------------------------------------------------------------------------BCD2CC: ; convert 2-byte BCDTEMP into 4-byte cc-code ; copy codes from Section-1.34. ; input via (03011) = MB, (03010) = LB ; output via (04003) = CC_DP3, (04002) = CC_DP2, (04001) = CC_DP1, (04000)-CC_DP0 ;---------------------------------------------------------------------------------------------CCX7SDD: ; transfer 4-byte cc-odes to CC7SDD unit ; copy codes from Section-1.34 ; input via (04003) = CC_DP3, (04002) = CC_DP2, (04001) = CC_DP1, (04000)-CC_DP0 ; output goes to Display Unit ; ---------------------------------------------------------------------------------------
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ACQCH0: Temperature Signal Acquisition Subroutine (ACQCH0) This SUR selects Ch0 by sending command bits of Table-20.1 into the ADC. Fig–P20.18 describes the pulse/timing system that must be followed to send the command bits of Table-20.1 into the ADC and then to read the digitized data from the ADC bit-by-bit with MS-bit first. Fig-20.19 describes an algorithm, which we may follow to (i) read the digitized data from the ADC with MS-bit first, (ii) convert them into parallel format, and then (iii) putting the data into ah-register. Table-20.1 : Single Ended MUX Mode of ADC0832 Bits over DI-pin (MUX Address) Analog Channel Selection B2 B1 B0 Ch0 Ch1 (START BIT = SB) (SGL/DIF) (ODD/SIGN) 1 1 0 Select (+) 1 1 1 Select (+) CLK(PC1)
t1 t2 t3 t5 t6 t4 1 CLK
t7 2 CLK
t8 3 CLK
t9 t10 CK7 CK6 CK5 CK4 CK3 CK2 CK1 CK0
CS/(PC0)
DI(PC2) DO(PC4)
SB
SGL
ODD
Disable
Disable
Data Ready : 0 or 1
MUX Settle and Conversion Time > 32uS
DB7 DB6 DB5 DB4 DB3 DB2 DB1 DB0
Htms2ch.vsd
Figure-20.18: Timing Diagram of ADC0832 ADC START:
NOP
L1: Initialize: Load 00 into ah Load 08h into cl
L2: Generate next CLK Pulse at PC1-pin
Read Data From PC4
L3: Y PC4=LH ?
L4:
Data bit=0
L8:
Data bit=1 N
Load LL into C-bit
Load LH into C-bit
L5:
b7 Rotate left through CF By 1-bit of (ah)
CF
b0
(ah)
L6: N Data Read Done ?
L7:
Y Halt Serial-data-readx : 11-03-2011
Figure20.19: Data Read Flow Chart of ADC0832 ADC
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Assembly Codes: ACQCH0: ; Inputs : none. ; Output : 8-bit data in ah-register. ;--- acquiring Ch-0 -------------------------------------------------------mov cl, 08h ; number of clock pulses to acquire 8-bit data from ADC ;-- LL CK, LH CS/--mov al, 01h ; 0000 0001 = xxxx DO DI CK CS/ mov dx, PCR ; pointing Port-C out dx, al ;-- start conversion by making CS/-pin Low---------------------------mov al, 00h ; 0000 0000 = xxxx DO DI CK CS/ mov dx, PCR ; pointing Port-C out dx, al ;-- LH Start Bit (SB) : always High---------------------------------mov al, 04h ; 0000 0100 = xxxx DO DI CK CS/ mov dx, PCR ; pointing Port-C out dx, al ;-- assert CK to clock in SB------mov al, 06h ; 0000 0110 = xxxx DO DI CK CS/ mov dx, PCR ; pointing Port-C out dx, al mov mov out
al, 04h dx, PCR dx, al
; 0000 0100 = xxxx DO DI CK CS/ ; pointing Port-C
;-- SGL Bit (logic High)--------------------------------------------------mov al, 04h ; 0000 0100 = xxxx DO DI CK CS/ mov dx, PCR ; pointing Port-C out dx, al ;-- assert CK to clock in SB------mov al, 06h ; 0000 0110 = xxxx DO DI CK CS/ mov dx, PCR ; pointing Port-C out dx, al mov mov out
al, 04h dx, PCR dx, al
; 0000 0100 = xxxx DO DI CK CS/ ; pointing Port-C
;-- LL ODD/Sign Bit (LL)-------------------------------------------mov al, 00h ; 0000 0000 = xxxx DO DI CK CS/ mov dx, PCR ; pointing Port-C out dx, al ;-- assert CK to clock in SB------mov al, 02h ; 0000 0010 = xxxx DO DI CK CS/ mov dx, PCR ; pointing Port-C out dx, al mov al, 00h ; 0000 0000 = xxxx DO DI CK CS/ mov dx, PCR ; pointing Port-C out dx, al ;------------------------------------------------------------------------------call READADC ; read serial data and convert to parallel ;----- deselect ADC by making CS/-pin High-----------------------------mov al, 01h ; 0000 0100 = xxxx DO DI CK CS/ mov dx, PCR ; pointing Port-C out dx, al ;-----------------------------------------------------------------------------------
101
ret ; acquisition done, data (VTH) in ah-register. ;================================================= READADC: mov ah, 00h ; parallel data collector FRQ101: ;--assert clock to read data MS-bit first------mov al, 02h mov dx, 3604h out dx, al mov mov out
LX2:
FRQ11:
al, 00h dx, 3604h dx, al
;----read bit from PC4-----mov dx, 3604h in al, dx and al, 10h sub al, 10h jz LX2 jmp FRQ11 stc rcl ah, 01h jmp FRQ11A clc rcl ah, 01h
FRQ11A: dec cl ; cl holds number of clock pulses = 08 jnz FRQ101 ret ;----------------------------------------------------------------------------------------------`
BCD Digit to CC-code Conversion Subroutine (BCD2CC) Assume that we have measured the room temperature as 25.300C. The quantity has been kept as 2530 into the memory locations 03000h and 03001h of the DSM of Fig-P1.15. The decimal point is in the mind of the programmer and will be added with digit-5 at the time of showing the temperature on 7SDD unit of Fig-P1.8. To show the digits of the temperature at DP0-DP3 position of the 7SDD unit of Fig-7.8, we need to know the cc-codes of these digits. The cc-codes have been kept in a ‘Lookup Table (LUT)’ of Fig-P1.8. Now, we need a software subroutine (called BCD2CC, Fig-P1.19), which will (i) read a digit from the BCD Table, (ii) consult the LUT to obtain the cc-code for the digit, and (iii) store the cc-code into the CC Table. BCD Table in DSM Location 04FFF
BCD Byte
CC Table in DSM
SUR
Display Positions
BCD2CC
Lookup Table (LUT) in ESM Digit Vs CC-code 05001=0000:5000+01 = Seg (es):off(di) + digit (bp) 04000 03FFF
03011 03010
30 25
DP2 DP3 DP0 DP1
03001 03000
Loc. 05009 05008 05007 05006 05005 05004 05003 05002 05001 05000
Digit 9 8 7 6 5 4 3 2 1 0
CC-code 6F 7F 07 7D 6D 66 4B 5B 06 3F
Location 04FFF
04003 04002 04001 04000 03FFF
cc-code
cc-code cc-code cc-code cc-code
of of of of
Display Positions
0 3 5 2
DP3 DP2 DP1 DP0
03001 03000 bcd2cc
Figure-20.20: Data Structure for BCD2CC Conversion Subroutine Assembly Instructions:
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;============================================================================= ; Inputs: BCD byte(s) via locations (03011) MB, (03010) = LB of BCD_Table ;Outputs: The cc-codes via (04003) = CC_DP3, …, (04000) n= CC_DP0 BCD2CC: S1L2A: S1L2B:
;-- extract 2 as 02 from 25 of BCD Table--mov ch, 02h mov bx, 3000h mov al, BYTE PTR ds:[bx] mov cl, 04h shr al, cl
; two byte BCD data to be converted to CC-codes ; al =25 ; al is to be shifted 4-bits to the right ; al = 02
;--- form address 05002 of LUT to obtain the cc-code of 02----mov dx, 0000h mov es, dx mov di, 5000h mov ah, 00h ; transfer 02 into bp-register as 0002 mov bp, ax ; bp = 0002 mov al, BYTE PTR es:[di+bp] ; ch = 5B = cc-code of 2 ;--- save the cc-code of 2 into CC Table---mov BYTE PTR ds:[bx+1000h], al ;-- get CC-code for the next digit (5) ------mov al, BYTE PTR ds:[bx] and al, 0h mov ah, 00h mov bp, ax mov al, BYTE PTR es:[si+bp]
; cc-code of 2 is saved in 04000h location ; al = 25 ; al = 05
; ch = 6D = cc-code of 5
;-- save cc-code of 5 into CC Table----mov BYTE PTR ds:[bx+1001h], al ;== get cc-codes for the remaining digits== dec ch jz S1L2C inc bx inc di jmp S1L2B ; CPU will repeat the conversion process
; check if more conversion is needed ; conversion done ; point next BCD byte in BCD Table ; point next location in CC Table
S1L2C: ret ; conversion complete, return to calling program ;=============================================================================
Subroutine to Transfer CC-codes to 7SDD (CCX7SD) Let us first note that the display unit is a ‘multiplexed display’. In a multiplexed display system (Fig-P1.8), the cc-type devices (here DP0-DP3) are all connected in parallel and their segments (p,…,a) are driven by Port-A of the 8255 IO controller. Therefore, to prevent the display from being frozen into a single digit, we need to refresh the display unit at regular intervals by sending the respective data to the display devices. The CCX7SDD subroutine works in the following ways: 1. 2. 3. 4.
It reads the content of location 04000h of CC-Table and sends it to DP0-position via 8255, It inserts some time delay so that the digit remains visible on the display device, The SUR repeats the above two steps for the display positions DP1 to DP3, The above three steps are repeated.
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bcd2cc
CC Table in DSM cc-code
M3: 8255
DP0 DP1 DP2 DP3
Display Positions PA7-PA0 3600h
04003
cc-code of 0
DP3
04002 04001
cc-code of 3 cc-code of 5
DP2 DP1
04000 03FFF
cc-code of 2
DP0
SUR CCX7SDD
3602h
Location 04FFF
8 p,…,a
cc0
cc1
cc2
PB0 PB1 PB2 PB3
CR 3606h 03001 03000
IO Controller
CC Table
CC7SDD
Figure-20.21: Explaining the Working Mechanism of Multiplexed Display Unit Assembly Codes: ;==================================================================== CCX7SDD: ; Inputs: The cc-codes are stored in the indicated memory locations of CC-Table ; Outputs: The BCD data appears on the display S2L1: mov ax, 0000h mov ds, ax mov bx, 3000h ; offset pointer ;--------------------------S2L2: mov dx, CR ; 8255 initialization mov al, Cbyte ; to set direction of IO lines of variable port out dx, al ;---------------------------S2L3: mov al, BYTE PTR ds:[bx+1000h] ; read 1st cc-byte from CC Table mov dx, PAR out dx, al ; 1st cc-byte is written into PAR for DP0 ;-------------mov dx, PBR mov al, 11111110b ; activate only PB0 out dx, al call TDEL ; insert time delay ;----------------------------S2L3: mov al, BYTE PTR ds:[bx+1001h] ; read 2nd cc-byte from CC Table mov dx, PAR out dx, al ; 2nd cc-byte is written into PAR for DP1 ;-------------mov dx, PBR mov al, 11111101b ; activate only PB1 out dx, al call TDEL ; insert time delay ;----------------------------S2L4: mov al, BYTE PTR ds:[bx+1002h] ; read 3rd cc-byte from CC Table
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cc3
mov dx, PAR out dx, al ; 3rd cc-byte is written into PAR for DP2 ;---------------------------------------------------------------------------------mov dx, PBR mov al, 11111011b ; activate only PB2 out dx, al call TDEL ; insert time delay ;----------------------------S2L5: mov al, BYTE PTR ds:[bx+1000h] ; read 4th cc-byte from CC Table mov dx, PAR out dx, al ; 4th cc-byte is written into PAR for DP3 ;-------------mov dx, PBR mov al, 11110111b ; activate only PB3 out dx, al call TDEL ; insert time delay ;----------------------------S2L6: ret ; return to mainline program and call CCX7SDD again ;----------------------------TDEL: mov cx, 00FFH ; Time Delay subroutine HERE: loop HERE ret ;============================================================================
20.5.4 Entering Binary Codes of Control Program (temp86.asm) into EPROMs (U7, U8) Procedures: (1) Open the source file …\MTK8086\temp86.asm and change the ORG to 0000h. Use MASM assembler and create temp86.abs (Intel-Hex Format) file from the source file temp86.asm. (2) Use driver program of any commercial Universal ROM Programmer (For example TopWinEn program of TOP2005 ROM Programmer) and open the file temp86.abs file. The file will be converted from Hex format into BINary format and will be displayed in the screen. Save it as temp86.bin. (3) Now use split2.exe program and divide the temp86.bin file into Even (EVN) and ODD (Odd) banks. The resultant files will have the names: temp86.evn and temp86.odd. (4) Again use the TopWinEn program and open the temp86.evn file. Using PageUp and PgaeDn command bring the cursor at the address line : 7FF0. (5) At location 7FF0 enter the code EA, at location 7FF1 enter the code 00, at location 7FF2 enter the code F0. Save the file and program (fuse) it into a 27C256 type EPROM. Label the EPROM as ROMEVN and place it on the breadboard at position of U7. (6) Open the file temp86.odd. Using PageUp and PgaeDn command bring the cursor at the address line : 7FF0. (7) At location 7FF0 enter the code 00, at location 7FF1 enter the code 00. Save the file and program (fuse) it into a 27C256 type EPROM. Label the EPROM as ROMODD and place it on the breadboard at position of U6. 20.5.5 Entering Binary Codes into Memory/Port Decoder (U12) (1) Contact at [email protected] to collect the binary file for the data of the U12. Fuse the codes into the 27C256 EPROM using a commercial ROM program. (2) Place the above programmed EPROM at the appropriate place of the breadboard of the layout of Fig-20.1, 20.3 20.5.6
Operation of the Stand-alone Temperature Meter of Breadboard
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(1) (2) (3) (3)
Apply power to the temperature meter. Press the reset switch K1 (Fig-P1.11). Check that the DP0-DP3 shows the room temperature. Check that for 100% sure the Temperature Meter made on the breadboard is not working.
Task-20.6 (1) (2) (3) (4) (5) (6)
Task-20.7 (1) (2) (3)
(4) (5) (6) (7) (8)
2
3 4
Making a Stand-alone Temperature Meter on PCB
Use OrCad package (Capture CIS) and capture the complete schematic diagram of the temperature meter. Use OrCad package (Layout Plus) and make double layer PCB Layout. Contact PCB maker in China or [email protected] and obtain few pieces of double layer PCBs. [email protected] is the email address of Golam Mostafa – author of this Lab Book. Solder the components and the ICs on the PCB. Apply power to the PCB. Press the reset switch. Check that the DP0-DP3 shows ambient temperature. Gently heat up the NTC sensor and check that the temperature of the display unit changes.
Task-20.8 1
Operation of Temperature Meter using MicroTalk-8086 Trainer
Place the Temperature Sensor (NTC), ADC (ADC0832) and the Display Devices (DP0DP3) on the breadboard of the MicroTalk-8086 Trainer (Fig-P1.2). Make connections among the NTC, ADC, DP0-DP2, and 8255 of the MicroTalk-8086 as per diagrams of Fig-P1.7, P1.8 and P1.14. Assemble the temp86.asm program of Section-1.4.3 and create temp86.abs file. Download the temp86.abs file into the RAM space of MicroTalk-8086 and execute it. Check that the DP0-DP3 shows the room temperature (approximately). Gently, heat up the NTC sensor and check that the display changes.
Questions and Answers (Solve as many as you can)
Write down the names of components ICs that are needed to build 8086 based Temperature Meter. Temperature Sensor : NTC Analog-to-Digital Converter : ADC0832 PIO Controller : 8255 Microprocessor : 8086 CC-type 7-segment Display : DP0-DP3 Clock Chip : 8284 EPROM : 3x27C256 RAM : 2x62256 Latch : 3x74LS373 Write down the names of the resources that are needed to build 8086 based Temperature Meter. MicroTalk-8086 MASM Assembler TOP2005 OrCad Software Download data sheets of ADC0832 and study its architecture and programming. Reduce the numbers of assembly codes for the READADC (Page-102) subroutine.
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