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Mechatronics EME154 Professor Kazuo Yamazaki Lab Assignment: Week 2 Materials List: JM552-SBC JM552-SBC Experimentation Board RS232 Serial Cable JM552-SBC Accessory I/O Board MPS1.0 JM-552 Simulator The Instructor will supply all materials for this lab Digital Input and Output Processing and Control Objective: Getting familiar with the simple digital input output control using JM-552 I/O: How to access the I/O ports on BASIC-52 chip of JM-552. How to access the Intel's 8255A Programmable Peripheral Interface (PPI) How to write the event-driven I/O control BASIC program. How to write the timer-driven I/O control BAISIC program. In the mechatronics control, the controller needs to receive the inputs from the outside, process them and output the electric signals to the outside based on the program execution. Although the signals to be handled may be digital or analog signals, the most and basic signals used in the mechatronics systems are the digital signals. The digital signals to and from the microprocessor and its peripheral chips are typically 0/5 volts digital signal. The place, through which the signals are received or from which, the signals are sent out is called "I/O ports". The I/O port can be regarded as one kind of memory from the microprocessor and also can be regarded as physical electric signal (0/5 volts) output or input terminal. Since the microprocessor handles the data as a unit of 8 bits (1 byte), the I/O port usually has an 8bit structure. In order to handle the physical electric signal, microprocessor or peripheral chip has I/O pins, each of which represents one bit of such an 8-bit I/O port. In JM-552 system, there are two types of I/O ports available. One is on-chip I/O port on 80C552 Chip (Microprocessor) and the other is the I/O port on 8255A Programmable Peripheral Interface (PPI) on JM-552 board. 1/22 EME154_2008S_LAB2 4/8/2008 In this Lab3, JM-552 is connected to the I/O Accessory board as shown in the picture below. 10 bit LED Block #2 SW 2 10 bit LED Block #1 SW 1 10 bit DIP Switch JM-552 Accessory I/O Board The I/O accessory board is equipped with two 10 bit LED (Light Emitting Diode) display blocks (as output device), 2 micro momentary switches (as input device), and one 10 bit snap DIP switch (as input device). The circuit diagram of the I/O accessory board is shown at the end of this handout. As you can see in the circuit diagram, one LED block (LED#1) is connected directly to the Port 1 of the 80552 microcontroller and the other LED block (LED#2) is connected to Port C of 8255A PPI chip. In BASIC 52, PORT1 command is available to access the port 1 of 80552 microcontroller. Accessing Port 1 Assignment 2-1: In this assignment, let s study how to control the LED block display by using PORT1 command. In order to turn on and off an LED on the 80C552 s Port 1, Pin 7 the most significant bit) which is connected to the most left LED segment (bit 9) of LED block #1. The segment will be turned on and off once per specified time (as a unit of second). The program also displays the elapsed time, the logic level (1 or 0) of PORT 1 Pin7, and the processing time of each interrupt process. 10 REM Program toggles P1.7 once per specified time (as unit of one second) 20 XTAL = 15142300 :Clear 30 INPUT "Input Number of Toggles = ", J 2/22 EME154_2008S_LAB2 4/8/2008 40 INPUT "Input ON/OFF Period (SEC) = ", P 50 Time = 0 :REM Initialize the timer to 0 60 I=1 :REM Initialize the cycle counter 70 E=TIME :REM E is the vaiable to measure the processing time 80 CLS: CLOCK 1 :REM Starts the realtime clock 90 ONTIME P, 120 :REM when Time =1, execute line 100 (Interrupt service) 100 IF I>J THEN END 110 GOTO 90 120 E=E+TIME 130 Time = 0 :REM Initialize the timer to 0 for causing next interrupt 140 SETCUR(2,1):PRINT USING(###),I,"ELAPSED TIME", 150 PRINT USING(##.###),E, 160 I=I+1 170 PORT1=PORT1.XOR.80H :REM Toggles Port 1, bit 7 180 PRINT USING(#)," Port 1, bit 7 = ", (PORT1.AND.80H)/80H," ", 190 PRINT USING(#.###),TIME,CR, 200 RETI :REM Return to the Main Program In order to access the I/O through the 8255A PPI chip, the physical address assigned to these ports should be used. As explained in the lectures as well as you studied as a reading assignment, 8255A has four-byte data storage. Three out of four bytes are pinned out as I/O lines. The other one is the control word register, which is used for configuration of the I/O pin assignment. Accessing I/O through 8255A PPI Assignment 2-2: The assignment is to study how to access the memory-mapped I/Os, which are connected through 8255A PPI. In order to access memory mapped I/Os, it is necessary to use the memory access commands. In BASIC-52, three different commands for accessing the memory locations depending on the memory type of the system as follows: XBY[address] : To access the external data memory DBY[address] : To access the internal data memory CBY[address] : To access the program memory In the JM-552 system, 8255A is connected to the external memory location from 0FE00H to 0FE03H. As shown in the JM-552 figure the addresses are assigned as follows: 3/22 EME154_2008S_LAB2 4/8/2008 Address 0FE00H 0FE01H 0FE02H 0FE03H Registers Port A Port B Port C Control Word Since the 8255A is in the external memory area, XBY statement should be used to access the I/O. As the circuit diagram indicates, LED block #2 is connected to Port C of 8255A whose location is 0FE02H. The following program is to flash top 8bits of the two LED blocks alternately with the cycle time of 2 seconds. The number of flashing cycles can be defined. 10 REM Alternates 2 LED Block Flashing for Specified Times 20 Clear 30 XTAL=15142300 40 W=0FE03H : P=0FE02H 50 XBY(W)=080H :XBY(P)=0FFH 60 TIME=0 70 I=1 :J=1 80 INPUT "Enter flashing cycles = ", N 90 CLS: CLOCK1 100 ONTIME 1, 130 110 IF J>2*N+1 THEN END 120 GOTO 100 130 TIME =0 140 IF J=2*N+1 THEN XBY(P)=0FFH :PORT1=0FFH :END 150 IF I=0 Then XBY(P)=0FFH :PORT1=0 :I=1 :GOTO 170 160 XBY(P)=0 :PORT1=0FFH :I=0 170 K=INT(J/2) 180 SETCUR(2,2):PRINT K, I, CR, :J=J+1 190 RETI Accessing Port 3 I/O Assignment 2-3 The assignment is to study how to access the port 3, which holds push switch 1 and 2 input of JM-552 I/O accessory board. Since BASIC-52 has no statement to access the port3 (Only PORT1 command is available to access the Port 1), Port 3 access driver should be created as assembler subroutine and CALL command is used to read the Port 3 data. The following program should be written and executed to understand how to detect the push switch 1 and 2 status through port3. 1 REM PORT3 READ FOR POUSH SWITCH CHECK 2 REM The following is the machine code of port3 accssess driver subroutine 4/22 EME154_2008S_LAB2 4/8/2008 3 REM One this subroutine is called by BASIC "CALL 9000H" statement, 4 REM Port 3 content is stored in Internal memory location 21H 11 REM ORG 9000H 12 REM Push PSW 13 REM Push a 14 REM orl psw, #0x18 15 REM MOV 021H, 0B0H 16 REM pop a 17 REM pop psw 18 REM RET 20 XBY(9000H)=0C0H 21 XBY(9001H)=0D0H 22 XBY(9002H)=0C0H 23 XBY(9003H)=0E0H 24 XBY(9004H)=43H 25 XBY(9005H)=0D0H 26 XBY(9006H)=18H 27 XBY(9007H)=85H 28 XBY(9008H)=0B0H 29 XBY(9009H)=21H 30 XBY(900AH)=0D0H 31 XBY(900BH)=0E0H 32 XBY(900CH)=0D0H 33 XBY(900DH)=0D0H 34 XBY(900EH)=22H 95 REM End of driver subroutine 98 CLS: Print "Please press one button." 99 REM Start of main program of switch detection 100 CALL 9000H :REM Get Port3 content to internal memory 21H 110 A= DBY(21H).AND.18H :REM Bit 3 and Bit 4 is retrieved+ 115 SETCUR(2,4):REM:This sentence is very important for display 120 IF A=8 Then Print "Switch 1 is depressed",CR,: GOTO 100 :REM P3.4 is SW1 130 IF A=16 Then Print "Switch 2 is depressed",CR, : GOTO 100 :REM P3.3 is SW2 140 GOTO 100 Simultaneous execution technique of free-time program and interrupt program Objective: 1. Understand how to organize the simultaneous execution of free time program and interrupt program. 2. Understand how to write, assemble and execute the assembler written program. Approach: 1. Understand the necessity of free time system execution and interrupt execution in 5/22 EME154_2008S_LAB2 4/8/2008 mechatronics control software. 2. Understand how to organize the timer interrupt program. 3. Understand how to write the timer interrupt program using assembler language. 4. Understand the example of co-execution (simultaneous execution) of free time program and timer interrupt program. 5. Execute the example programs. 6. Modify the example program to verify your understanding. Free-time program and interrupt program As you have learned in the past lectures, two kinds of software are generally required in the mechatronics control. They are free-time program and interrupt program. The free-time system is a sort of the dedicated operating system, which supervises a series of tasks in an infinite loop fashion. The free-time process starts with initialization followed by infinite loop of repetitive execution of the sequential tasks, which consists of system diagnostics - machine status scan - mode control supervision - respective mode execution output control supervision. In mechatronics control system, a certain task needs to be executed very accurately in accordance with time or event. For example, in motor control, reading a position sensor with constant sampling rate is required to detect the actual speed of rotation. With the constant time period established and the difference between two adjacent readings of the position sensor by sampling, the rotational speed over the sampling period can be calculated. This requires the time interrupt base sampling and calculation. Another example is the event-driven interrupt processing. During the execution of free time tasks, if the machine hits the travel limit sensor, the machine motion should immediately be stopped. Otherwise, the machine will collide at the end of the travel mechanism and the machine will be broken. If the entire execution of the free-time tasks can instantly be completed with elapsed time zero, there is no need to have interrupt-based processing because these tasks can be integrated into the free-time tasks. However, the actual execution of free-time tasks takes a time depending on the volume of their instruction codes and also since there are various tasks to be executed depending on the machine-control status, the time required for one loop free-time processing is not constant and not deterministic. In free-time tasks, the execution time is not so critical but a variety of tasks need to be executed with respect to the status of the system. Therefore, it is convenient to use the high level language to write the program. For interrupt-based tasks, the execution timing is critical and the time required to complete each task should be shortest as possible, it is desirable to use the assembler language to write the program for time-efficient execution. In the Lab, we will learn how to organize the free time system and time-interrupt program using the JM-552 system equipped with 80552 CPU. For free time tasks, we will mainly use BASIC-52 language and for time-interrupt program, we will use the Intel Assembly 8051 language. Time interrupt program First, let s study first, how to organize the time-interrupt program. In the most of microprocessors or microcontrollers, there is an embedded timer. The timer is used to generate the constant time-pitched timing signal for CPU. In 80552 6/22 EME154_2008S_LAB2 4/8/2008 microcontroller, there are two 16-bit timers, timer 0 and timer 1. These timers are used by BASIC-52 occasionally. But if you do not use a certain function of BASIC-52, you can use these timers for your own purpose. For details, read the explanation TIMER0 and TIMER1 on Page 92 of BASIC-52 Manual (attached). (TIMER2 should not be used, because it is always used by JM-5552) The mechanism of timer is just a counter. Every time when the pulse is given to the timer, the timer counts up its content and when the timer reaches the full counts (i.e. 0FFFFH for a 16-bit counter) and one more pulse is added then the timer gets overflow and the content becomes zero. At this instant, the timer generates the overflow carry signal to the control unit. If you configure the timer interrupt function in an appropriate mode (this will specifically be explained later) in advance, the control unit immediately suspends the on-going task when a overflow carry signal is detected and start the dedicated timer interrupt program which is located at the designated address. In JM-552 system, Timer 0 interrupt automatically starts the program located at 0FA0BH and Timer 1 interrupt automatically starts the program located at 0FA1BH. 7/22 EME154_2008S_LAB2 4/8/2008 How to configure the timer to cause timer interrupt in 80552 microcontroller To use the timer interrupt, the configuration of the timer and related register is required. The configuration steps are as follows: Step 1 Set a jump instruction at timer interrupt entry address. When the timer interrupt occurs, CPU hardware automatically starts the execution from the designated timer interrupt entry address. Since only several bytes of address space is assigned such interrupt entry point, usually long jump instruction is set to jump to the start location of actual timer interrupt service program The designated entry addresses of the TIMER0 and TIME1 in JM-552 system are FA0BH and FA1BH respectively as previously mentioned. Timer mode register set. There are several types of the timer operation. To select the specific timer mode, TMOD (Timer Mode Register) is located at the special function register 89H Use MODE 1 for simple timer configuration. Mode 1 is the configuration such that the timer high byte and the timer low byte are connected to form 16-bit timer. When the overflow occurs at the most significant bit of the timer high byte then the timer interrupt will occur. For details of TMOD set up, refer Page 195 of BASIC-52 Manual (attached). Anyway, for Mode 1 Timer mode for both TIMER0 and TIMER1, TMOD should be set 11H Step 3 Timer initial value set. To cause the timer interrupt at desired period of time, it is necessary to set up the timer with an initial value. In 80552 CPU, the timer content is counted up by one every time when 12 pulses of XTAL clock are received. This means that when the XTAL Frequency is 16 M (Mega) Hz, one count up period is 12/16M sec=0.75 microseconds =750 nanoseconds. Therefore, in order to cause 20 mili-seconds timer interrupt, 20000/0.75=26667 counts are needed to cause the interrupt. This means if you set the negative number 26667 in the timer as an initial value, after 26667 counts up, the overflow will occur and the timer interrupt will occur accordingly. 26667 in 16 bit signed integer expression is 97D5H. TIMER0 and TIMER1 are located in special 8/22 EME154_2008S_LAB2 4/8/2008 Step 2 function registers and the specific locations are as follows: TIMER0 high byte (TH0) address is 8CH TIMER0 low byte (TL0) address is 8AH TIMER1 high byte (TH1) address is 8DH TIMER1 low byte (TL1) address is 8BH Step 4 Start the timer. After set up the timer, the timer should be started. Start/stop control of the timer can be done by setting up the designated bit of the timer control register, TCON, which is located at 88H in the special function registers. For details, refer the page 197 of the BASIC-52 Manual. TIMER0 ON/OFF switch is bit 4 of TCON and TIMER1 ON/OFF switch is bit 6 of TCON Step 5 Set interrupt enable switch. As a final step to activate the timer interrupt mechanism, it is necessary to enable the timer interrupt. It can be done by setting the designated bits of the Interrupt Enable Control Register (IEC), which is located at 0A8H. For details of IEC, refer Page 196 of BASIC-52 Manual. How to write the assemble program for JM-552 As we have already studied, the assembler program can be written line-by-line using the structure: Symbol : Mnemonic code Operand1, Operand2, When writing the program, use Notepad software, which is available in WINDOWS accessory programs. As a practice of writing the assembler program, type in the following sample program as ;Timer 1 Interrupt configuration routine org 0x8500 push psw ; save current psw orl psw, #0x18 ; use register bank 3 from now on push acc ; save current accumulator push dpl ; save data pointer push dph mov dptr, #0xFA1B ; Timer 1 interrupt jump vector set mov a, #0x02 ; ljump INT1 (location 0x8550) movx @dptr, a inc dptr mov a, #0x85 movx @dptr, a inc dptr mov a, #0x50 movx @dptr, a ; timer 1 setup subroutine 9/22 EME154_2008S_LAB2 4/8/2008 mov tmod, #0x10 ;timer1 mode set mov tl1,#0xD5 ;Timer Value set 97D5h=timer initial value mov th1,#0x97 ;for 20msec interrupt mov 0x21,#0xFF ; Clear counter mov dptr, #0xfe03 ; set data pointer to 8255 control word address mov a,#0x80 movx @dptr, a ; set 8255 mode as all output setb tr1 ; Start timer orl ie,#0x88 ;timer 1 IE flag is on pop dph ; restore data pointer pop dpl pop acc ; restore accumulator pop psw ; restore psw RET ; return to the main routine ; Timer 1 interrupt service routine org 0x8550 ;Timer1 interrupt service (increment counter) INT1: ;timer1 time set push acc ; save accumulator orl psw, #0x18 ; use register bank 3 from now on mov tl1,#0xD5 ; timer initial value set mov th1,#0x97 dec 0x21 ; decrement counter (21H) ;output counter to 0xFE02 push dpl ; save data pointer push dph mov dptr, #0xfe02 mov a,0x21 movx @dptr, a ; output to LED data through 8255 pop dph ; rstore data pointer pop dpl pop acc ; restore accumulator pop psw ; restore psw reti ; return interrupt end After input the above program, store it with the file name LAB21.sim . The portion of the above program listed under the comment line ;Timer 1 Interrupt configuration routine is the subroutine to setup the timer interrupt. This subroutine should be located from address 8500H The portion of the above program listed under the comment line ;Timer1 interrupt service (increment counter) is the timer service routine, which should be located from the address 8550H. This particular program will count down the content of internal data memory 21H by one every time the timer interrupt occurs (i.e. every 20 mili-seconds when the clock is 6 MHz) and also output the content of memory 21H to the LED block 1 in each interrupt. 10/22 EME154_2008S_LAB2 4/8/2008 Special remarks when executing assembler program in JM-552 with BASIC-52 program. When executing the assembler program (either in regular or interrupt mode), special attention should be paid and a certain procedure should be taken in the beginning of the program and the end of program as follows: Basic attention Since BASIC interpreter is always running when the system is in the basic mode, many resources of CPU are being used by the basic interpreter. These resources are Accumulator(ACC), Program Status Word (PSW), Data Pointer(DPTR), Register Bank (RB) 0, 1, and 2. Therefore, when you execute the assembler program while the BASIC interpreter is running, you need to save these resources contents by using PUSH instruction in the beginning of assembler program. Also, you need to switch the register bank to be used to register bank 3. This can be done by setting bit 3 and bit 4 of PSW, which is located at address 0D0H in the special function registers. For details, read Chapter 9 (from page 104) of BASIC-52 Manual. Also, just before getting out from the assembler program, you have to restore the contents of the resources you have saved. To restore you can use POP instruction. Special Important Information on PSW save and restoration upon Timer Interrupt When timer interrupt occurs, the PSW is automatically saved into the stack area. Therefore, there is no need for the interrupt service program to save PSW in the beginning of the program, but just before getting out of timer interrupt program by RETI instruction, the program should perform POP PSW. There is no automatic restoration of PSW by hardware. Free-time program Example Here is a sample of free time program, which can be co-executed with the timer interrupt assembler program previously listed as an example. 10 REM Free Time Routine with Timer Interrupt 20 CALL 8500H 30 CLS 40 SETCUR(0,2) 50 PRINT "TIMER1 INTERRUPT START" 60 SETCUR(0,4) 70 PRINT " ", 256-DBY(21H) 80 KEY(0) 90 POP A 100 IF A=0 THEN GOTO 60 110 KEY(1) 120 POP A 130 B=A-49 140 IF B=0 Then GOTO 160 150 GOTO 60 160 END Type in the program and store it under the file name LAB24.bas . Also, slightly modify the abovementioned program as follows and store it under the name LAB25.bas 10 REM Free Time Routine with Timer Interrupt 20 CALL 8500H 11/22 EME154_2008S_LAB2 4/8/2008 30 CLS 40 SETCUR(0,2) 50 PRINT "TIMER1 INTERRUPT START" 60 SETCUR(0,4) 70 PRINT " ", 256-DBY(21H) 80 KEY(0) 90 POP A 100 IF A=0 THEN GOTO 150 110 KEY(1) 120 POP A 130 B=A-49 140 IF B=0 Then GOTO 190 150 FOR I=1 to 1000 160 J=I 170 NEXT I 180 GOTO 60 190 END Execution of example programs 1. Assemble the program, LAB21.sim using MPS1.0 2. Run the program LAB24.bas 3. Observe what is happening. 4. Repeat the steps 1-5 by just changing LAB24.bas to Lab 25.bas. 5. What is the difference? 12/22 EME154_2008S_LAB2 4/8/2008 80C552 Microcontroller PORT 3 (B0H) PORT 1(90H) Address, Data, and Control Bus 8255A PPI Control Word (0FE03H) PORT B (0FE01H) PORT C (OFE02H) GRND PORT A (0FE00H) 9876543210 I/O Accessory Board 10 bit LED Array #2 10 bit DIP Switch P3.4 9876543210 5V DIP SW bit 5,6,7,8,9,and 0 are not identified at this moment. JM-552 I/O PORT Connection 0000H System Program Memory 32 k byte ROM (U4) (user can not use) 7FFFH 8000H 7FFFH 0000H System Data Memory 32 k byte RAM (U5) (user can not use) FFH 00H Internal Data Memory User Program or Data Memory 32 k byte RAM (U6) FDFFH FE00H FE03H FF80H 82C55A PPI LCD JM-552 Memory Map 13/22 EME154_2008S_LAB2 4/8/2008 P1.7 P1.6 P1.5 P1.4 P1.3 P1.2 P1.1 P1.0 10 bit LED Array #1 P3.3 14/22 EME154_2008S_LAB2 4/8/2008 15/22 EME154_2008S_LAB2 4/8/2008 16/22 EME154_2008S_LAB2 4/8/2008 17/22 EME154_2008S_LAB2 4/8/2008 18/22 EME154_2008S_LAB2 4/8/2008 19/22 EME154_2008S_LAB2 4/8/2008 20/22 EME154_2008S_LAB2 4/8/2008 21/22 EME154_2008S_LAB2 4/8/2008 22/22 EME154_2008S_LAB2 4/8/2008

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