|
Q) You are required to read the 8 switches and control the LEDs using port A in real time. You need to control the LEDs in at least 3 different ways of circulation in real time, which should be selected by pushing different pushbuttons. You need to consider hardware connection yourself Can anyone help me to solve this task? I have just started learning assembly language for 68HC11 and needs some of your help. thnx Ryan |
|
|
Input/Output using port A
Started by ●August 21, 2004
Reply by ●August 21, 20042004-08-21
|
First step is figure out the steps in plain english. You can read 8 switches
with a LDAA PORTA instruction, and you can set 8 leds with the STAA PORTA instruction. Now you need to describe what you want to happen. Example, when you poush switch one, all 8 flash on and off once. When you push sw 2, all 8 flash one at a time, when you push switch 3, they reverse direction. Now you need to write a 'read the switch' subroutine.... hint... switch 1 is just getting pushed when bit one is all of a sudden lo, and it was hi last pass... you need to save the state last pass..... you need to write a loop that will delay 1ms... you can call that 100 times to delay 100ms, etc. Take a stab at it and come back in a couple hrs with something that 'almost works' and we'll help you debug it.... |
|
|
Reply by ●August 22, 20042004-08-22
|
--- In , "cheol1217" <cheol1217@y...> wrote: > Q) You are required to read the 8 switches and control the > LEDs using port A in real time. You need to control the LEDs > in at least 3 different ways of circulation in real time, > which should be selected by pushing different pushbuttons. > You need to consider hardware connection yourself > > Can anyone help me to solve this task? I have just started > learning assembly language for 68HC11 and needs some of your > help. Is this the extent of the description of the program you wish to create? It would help me if you could provide a more complete description, as Bob Gardner suggested in his response. If you are using a 68HC11A or E series device, you will not be able to drive 8 LEDs with it - not all of the Port A lines can be configured as outputs. Lines PA3 thru PA7 can be configured as (or are permanantly set as) outputs, but PA0, PA1 and PA2 are input- only. This is not the case with all HC11's - for example, the MC68HC11F1 can be configured to use all 8 Port A lines as outputs. If you are just getting started, you should go to the Motorola/Freescale website and download the M68HC11 Reference Manual and assimilate as much of its contents as you can.. It sounds like you have already started to study the instruction set, which is a good thing. The next thing you should read about are the descriptions of the way the I/O ports work and perhaps the timer subsystem. Don't worry too much about the 'handshake modes' offered for Port B and Port C - these modes are not often used and probably would not be of much use to you in your application. Break down the task you want to perform into small sub-sections, small enough so the solution for each is fairly obvious. Don't worry too much if there are some tasks you do not know how to do, like "how do I delay a tenth of a second" or "how do I read my pushbuttons reliably". These are topics that we can help you with. But we can't write the entire program for you, and even if we could, it would do you little benefit to have someone else do it for you, as you would not learn nearly as much. It would be helpful if you could describe for us what sort of hardware platform you are using. Will you be building the entire system, including the HC11 and support hardware yourself? Or are you using a pre-built 'evaluation board' that you only need to add your LEDs and switches to? Will you be using (or does your eval board have) external RAM and ROM/EEPROM/FLASH, or will you be using the HC11 in 'single chip' mode? Will you be using the MC68HC(7)11Ex device, or a different HC11 variant, like the MC68HC11F1? Answers to these questions will help us help you. |
|
|
Reply by ●August 22, 20042004-08-22
Reply by ●August 22, 20042004-08-22
|
> Is this the extent of the description of the program you wish to > create? It would help me if you could provide a more complete > description, as Bob Gardner suggested in his response. > > If you are using a 68HC11A or E series device, you will not be able > to drive 8 LEDs with it - not all of the Port A lines can be > configured as outputs. Lines PA3 thru PA7 can be configured as (or > are permanantly set as) outputs, but PA0, PA1 and PA2 are input- > only. This is not the case with all HC11's - for example, the > MC68HC11F1 can be configured to use all 8 Port A lines as outputs. > > If you are just getting started, you should go to the > Motorola/Freescale website and download the M68HC11 Reference Manual > and assimilate as much of its contents as you can.. It sounds like > you have already started to study the instruction set, which is a > good thing. The next thing you should read about are the > descriptions of the way the I/O ports work and perhaps the timer > subsystem. Don't worry too much about the 'handshake modes' offered > for Port B and Port C - these modes are not often used and probably > would not be of much use to you in your application. > > Break down the task you want to perform into small sub-sections, > small enough so the solution for each is fairly obvious. Don't > worry too much if there are some tasks you do not know how to do, > like "how do I delay a tenth of a second" or "how do I read my > pushbuttons reliably". These are topics that we can help you with. > But we can't write the entire program for you, and even if we could, > it would do you little benefit to have someone else do it for you, > as you would not learn nearly as much. > > It would be helpful if you could describe for us what sort of > hardware platform you are using. Will you be building the entire > system, including the HC11 and support hardware yourself? Or are > you using a pre-built 'evaluation board' that you only need to add > your LEDs and switches to? Will you be using (or does your eval > board have) external RAM and ROM/EEPROM/FLASH, or will you be using > the HC11 in 'single chip' mode? Will you be using the MC68HC(7) 11Ex > device, or a different HC11 variant, like the MC68HC11F1? Answers > to these questions will help us help you. Yeah I have just started learning the assembly language from my college 5 weeks ago. Since I am only a beginner I am not quite sure what system we are running this. I did not know there were different series of 68HC11 such as A or E. I programme using a software package called "THRsim11". I am using a pre-built 'evaluation board' that only need LEDs and switches. This is run using single mode, using the built in rams. This is the information I know for now But I got some ideas from reply that Bob Gardner has written. Thnx for your time. I appreciate it. Ryan |
|
|
Reply by ●August 22, 20042004-08-22
|
--- In , "cheol1217" <cheol1217@y...> wrote: > Yeah I have just started learning the assembly language from my > college 5 weeks ago. Since I am only a beginner I am not quite > sure what system we are running this. I did not know there were > different series of 68HC11 such as A or E. > > I programme using a software package called "THRsim11". I am using > a pre-built 'evaluation board' that only need LEDs and switches. > This is run using single mode, using the built in rams. Ok, thanks for the info. Based on what you've described above, I would recommend that you use PORT B to control your LEDs and PORT E (or perhaps PORT C) for your switches. PORT A is not a good choice for control of 8 LEDs, for reasons I discussed earlier. Note that the HC11 cannot source or sink sufficient current on its output pins to drive LEDs directly, so you will need to use transistors or some other power-driver IC (such as a ULN2803) to interface the LEDs to the HC11 port. Let me know if you are having any difficulties on the hardware side. Follow Bob's (and my) advice, try to solve at least some of your problems in small pieces, and get back to us if you encounter any problems. -- Mark |
Reply by ●August 24, 20042004-08-24
|
Hi, I managed to get input from three different switches and control the LEDS without using interrupt. When I run this program step by step there is no problem, however if I run the program automatically I can press a switch only in the first time and programme just ends somehow. I think I need some kind of time control using time interrupts, but it seems so hard understand. Can you plz give me some hints how to do it. thnx! Ryan ----below are main part of the code--------------- LIST FCB $9E,$9D,$9B,$97,$8F,$BF,$DF,$1F LIST2 FCB $1E,$DD,$BB,$87,$87,$BB,$DD,$1E LIST3 FCB $9F,$60,$9F,$60,$9F,$60,$9F,$60 START LDX #REGBS ; register base address BCLR SPCR,X,%00100000 ; disable WOM outputs LDAA #%11111111 ; enable SRAM (CE2) and select banks STAA BANKSR ; select banks (Flash and RAM) ; RTI vector to 00EB: 7E,00,00 (for Buffalo) LDD #RTI ; setup interrupt vector in RAM STD $00EC ; just part of Buffalo LOOP LDAA #%11111000 ; make 3 lower bit of Port-A inputs STAA DDRA,X BRCLR PORTA,X 1 MODE1 BRCLR PORTA,X 2 STOP BRCLR PORTA,X 4 STOP BRA LOOP MODE1 LDAA #%11111111 ; make ALL bits output STAA DDRA,X LDY #LIST RUN1 LDAA 0,Y STAA PORTA,X LDX #$00FF ; delay T1 DEX BNE T1 ; delay loop INY CPY #$3008 BNE RUN1 BRA LOOP STOP JMP $8000 ----this is the whole code-------------------- ; EQUATES - SYSTEM - RAM - ROM - EEPROM * ; * ;******************************************************************** **** ; SYSTEM ; * REGBS EQU $1000 ; START OF REGISTERS x000 to x05F CSIO1 EQU $1600 ; bank select address x600 to x7FF CSIO2 EQU $1800 ; external chip select x800 to xFFF RAM EQU $0000 ; START OF CPU RAM 0000 to 3FFF FLS_SA EQU $8000 ; START OF FLASH 8000 FLS_EA EQU $0FDFF ; END OF FLASH FDFF EEP_SA EQU $0FE00 ; START OF EEPROM FE00 EEP_EA EQU $0FFFF ; END OF EEPROM FFFF ;******************************************************************** **** ; REGISTER * * ;******************************************************************** **** PORTA EQU $00 ; PORT A DDRA EQU $01 ; PORT A DDR PORTG EQU $02 ; PORT G DDRG EQU $03 ; PORT G DDR PORTB EQU $04 ; PORT B PORTCL EQU $05 ; PROT C LATCHED DATA REG. DDRC EQU $07 ; DATA DIRECTION REGISTER C PORTD EQU $08 ; PORT D DDRD EQU $09 ; DATA DIRECTION REGISTER D PORTE EQU $0A ; PORT E CFORC EQU $0B ; TIMER COMPARE FORCE REG. OC1M EQU $0C ; O/P COMPARE 1 MASK REG. OC1D EQU $0D ; O/P COMPARE 1 DATA REG TCNT EQU $0E ; TIMER COUNT H TCNTL EQU $0F ; L TIC1 EQU $10 ; TIMER O/P COMPARE 1 H TIC1L EQU $11 ; 1 L TIC2 EQU $12 ; 2 H TIC2L EQU $13 ; 2 L TIC3 EQU $14 ; 3 H TIC3L EQU $15 ; 3 L TOC1 EQU $16 ; TIMER O/P COMPARE 1 H TOC1L EQU $17 ; 1 L TOC2 EQU $18 ; 2 H TOC2L EQU $19 ; 2 L TOC3 EQU $1A ; 3 H TOC3L EQU $1B ; 3 L TOC4 EQU $1C ; 4 H TOC4L EQU $1D ; 4 L TOC5 EQU $1E ; 5 H TOC5L EQU $1F ; 5 L TCTL1 EQU $20 ; TIMER CONTROL REG 1 TCTL2 EQU $21 ; TIMER CONTROL REG 2 TMSK1 EQU $22 ; TIMER MASK 1 TFLG1 EQU $23 ; TIMER FLAG 1 TMSK2 EQU $24 ; TIMER MASK 2 TFLG2 EQU $25 ; TIMER FLAG 2 PACTL EQU $26 ; PULSE ACCUMULATOR CONT. REG. PACNT EQU $27 ; PULSE ACCUMULATOR COUNT REG. SPCR EQU $28 ; SPSR EQU $29 ; SPDR EQU $2A ; BAUD EQU $2B ; SCI BAUD REG SCCR1 EQU $2C ; SCI CONTROL 1 REG SCCR2 EQU $2D ; SCI CONTROL 2 REG SCSR EQU $2E ; SCI STATUS REG SCDR EQU $2F ; SCI DATA REG ADCTL EQU $30 ; ADR1 EQU $31 ; ADR2 EQU $32 ; ADR3 EQU $33 ; ADR4 EQU $34 ; BPROT EQU $35 ; OPTION EQU $39 ; OPTION REG COPRST EQU $3A ; COP RESET REG PPROG EQU REGBS+$3B ; EEPROM PROG REG HPRIO EQU $3C ; HPRIO REG INIT EQU $3C ; INIT CONFIG EQU $3F ; CONFIG REG CSSTRH EQU $5C ; CS CYCLE STRETCH CSCTL EQU $5D ; CS CONTROL CSGADR EQU $5E ; GENERAL PURPOSE CS (RAM) CSGSIZ EQU $5F ; GENERAL PURPOSE CS SIZE BANKSR EQU $1600 ; BANK SELECT REGISTER ;******************************************************************** **** ; CONSTANTS * * ;******************************************************************** **** PIEZO EQU %00010000 ; EVB_3A piezo output (D4) TDRE EQU $80 RDRF EQU $20 MDA EQU $20 SMOD EQU $40 MS10 EQU 10000/3 US500 EQU 500/3 ; MEMORY ; DFB " rti_example1.asm V1.00 02 August 2003 " ; DFB " (c) 2002 PMB " ; Variables in zero-page RAM RTICNT EQU $0006 ; Counter for dump routine TEMP1 EQU $0007 ; 2 ; Temp variable 1 FLAGS1 EQU $0009 ; status flags BANKSS EQU $0013 ; bank select register main copy BANKST EQU $0014 ; bank select register temp copy ORG $3000 LIST FCB $9E,$9D,$9B,$97,$8F,$BF,$DF,$1F LIST2 FCB $1E,$DD,$BB,$87,$87,$BB,$DD,$1E LIST3 FCB $9F,$60,$9F,$60,$9F,$60,$9F,$60 ;******************************************************************** **** ;************; P R O G R A M S T A R T S H E R E ******************** ;******************************************************************** **** ; INITIALISATION ROUTINE ORG $2000 ; initial RAM address ;************ ; INITALISATION START LDX #REGBS ; register base address BCLR SPCR,X,%00100000 ; disable WOM outputs LDAA #%11111111 ; enable SRAM (CE2) and select banks STAA BANKSR ; select banks (Flash and RAM) ; RTI vector to 00EB: 7E,00,00 (for Buffalo) LDD #RTI ; setup interrupt vector in RAM STD $00EC ; just part of Buffalo ;************ ; SET & ENABLE REAL TIME INTERRUPT ; PACTL = nnnnnn10 AT 8 MHz FOR 16.38 mS ; PACTL = nnnnnn01 AT 4 MHz FOR 16.38 mS ; PACTL = nnnn1nnn = DDRA BIT 3 (1=OUTPUT) BSET PACTL,X,%00001011 ; set slowest RTI rate BSET TMSK2,X,%01000000 ; enable RTI interrupt ; delay LDAA #$11 ;01 ; preset RTI cycle counter STAA RTICNT ; " ************* LOOP LDAA #%11111000 ; make 3 lower bit of Port-A inputs STAA DDRA,X BRCLR PORTA,X 1 MODE1 BRCLR PORTA,X 2 STOP BRCLR PORTA,X 4 STOP BRA LOOP MODE1 LDAA #%11111111 ; make ALL bits output STAA DDRA,X LDY #LIST RUN1 LDAA 0,Y STAA PORTA,X LDX #$00FF ; delay T1 DEX BNE T1 ; delay loop INY CPY #$3008 BNE RUN1 BRA LOOP STOP JMP $8000 ;************ ; other initalisation CONT BSET DDRD,X,PIEZO ; make piezo an output LDAA #%11111111 ; make Port-A all outputs STAA DDRA,X ; " LDY #LIST STY $3500 CLI ; enable all interrupts ; This is the foreground function. ;************ ; Pulse the PIEZO buzzer TESTB LDX #$1000 ; register base address TSTB1 BRSET PORTD,X,PIEZO,TSTB2 ; check PIEZO ;BSET PORTD,X,PIEZO ; PIEZO = on BRA TSTB3 TSTB2 BCLR PORTD,X,PIEZO ; PIEZO = off TSTB3 LDY #$0FFFF ; delay TSTB4 DEY BNE TSTB4 ; delay loop BRA TSTB1 ; next cycle ; RTI -- service routine, occurs everyEVERY 16.384mS. Used for timing ;********************************************************************* *** ;********************************************************************* *** ;********************************************************************* *** RTI SEI LDX #REGBS ; load for indexed addressing LDY $3500 BSET TFLG2,X,%01000000 ; clear RTI interrupt flag ;************ DEC RTICNT ; update interrupt counter BNE RTI_99 ; no yet ready ;************ ; safety check TST PORTA,X ; test Port-A BNE RTI_0 ; ok, continue INC PORTA,X ; oops, fix Port-A RTI_0 CPY #$3008 ; reach to the end of LIST? BEQ RTI_1 ; Yes, start again LDAA 0,Y ; no, read data STAA PORTA,X ; send to PortA INY ; next data STY $3500 BRA RTI_98 RTI_1 LDY #$3000 STY $3500 ; right RTI_98 LDAA #80 ; reset delay counter STAA RTICNT ; " RTI_99 RTI ; finished, return from interrupt ;********************************************************************* *** ;********************************************************************* *** ;********************************************************************* *** ;********************************************************************* *** ;********************************************************************* *** END |
|
|
Reply by ●August 24, 20042004-08-24
|
Hi Ryan, you kill the x register in CW> LDX #$00FF ; delay CW> T1 DEX CW> BNE T1 ; delay loop but you need it later in Loop. So do: CW> LOOP LDAA #%11111000 ; make 3 lower bit of CW> Port-A inputs LDX #REGBS ; register base CW> STAA DDRA,X also, for moving code (question of stile): CW> INY CW> CPY #$3008 ; not good - better cpy #LIST + 8 CW> BNE RUN1 CW> BRA LOOP Werner |
Reply by ●August 24, 20042004-08-24
|
--- In , "CW" <cheol1217@y...> wrote: > Hi, I managed to get input from three different switches and > control the LEDS without using interrupt. When I run this program > step by step there is no problem, however if I run the program > automatically I can press a switch only in the first time and > programme just ends somehow. I think I need some kind of time > control using time interrupts, but it seems so hard understand. > Can you plz give me some hints how to do it. I have taken a look at the code you posted, and have noted a few problems. Some of the 'problems' I discuss here are merely matters of style; but there are also some bonafide bugs that I have found as well. - Near label "LOOP" you have a LDAA #%11111000 / STAA DDRA,X sequence. Are you sure that your HC11 variant has a DDRA? The HC11 A and E series parts do NOT provide a DDRA register; the direction of most Port A bits is fixed (excepting PA3 and PA7, which are controlled via the PACTL register). - Near label "START" you initialize the RTI pseudo-vector. For sake of completeness, and to allow your program to run in debug environments other than BUFFALO, it is 'good practice' to initialize the JMP instruction opcode as well. You should add a LDAA #$7E / STAA $00EB sequence to your init code. Also, as a matter of style, you should declare a symbol that contains the location of the RTI pseudo-vector, and use it instead of a literal constant, like this: RTIVEC EQU $00EB ;RTI pseudo-vector ... LDAA #$7E ;JMP instruction opcode STAA RTIVEC ;Place in RTI pseudo-vector location LDD #RTI ;Address of RTI ISR STD RTIVEC+1 ;Copy to RTI pseudo-vector - It appears as if you are attempting to use Port A to both read your switches and control LEDs. This would be OK if you had only buttons attached to PA0-PA2, and LEDs only attached to PA3-PA7. Based on what I see in your code, it appears as if you have both LEDs and switches attached to PA0-PA2, which is not a Good Thing. Also, unless you happen to be using a 'HC11F1 device, PA0-PA2 are input-only (see comment regarding DDRA above). If you ARE using a F1, when you configure DDRA to set PA0-PA7 as outputs, your button (s), if pressed, will attempt to force a OUTPUT line to a fixed state - you could damage the pin drivers for those ports if the output level (as set by PORTA) conflicts with the level that the switches are trying to assert when they are pressed. It would be much better if you moved your pushbutton switches to a different port, say, Port E (any port capable of being configured as an input port will do). - Near label "T1" you initialize the X register to $00FF and use it as a delay counter. After the delay is complete, you jump to LOOP, which contains code that assumes that X is equal to REGBAS. You should make sure you re-initialize X to REGBAS following your delay routine. Better yet, add a LDX #REGBS instruction at the start of the LOOP routine. In this same block of code, you check for the end-of-table condition using 'CPY #$3008'. It would be better (as a matter of good style) to change this to 'CPY #LIST+8' - or, better yet, declare your table like this: LIST FCB $9E,$9D,$9B,$97,$8F,$BF,$DF,$1F ENDLIST EQU * and change the CPY end-of-table check to 'CPY #ENDLIST'. This way, if you decide to change the length of the table, your code will 'automagically' adjust the address that the CPY instruction checks for. You can use this same 'trick' for your tables LIST1 and LIST2 - add symbols such as 'ENDLIST1' and 'ENDLIST2', declared as shown above for 'ENDLIST'. - In various sections of your code, I note that you sometimes perform a 'LDX #$1000' instead of a 'LDX #REGBS'. As a matter of good style, you should always use the symbolic constant REGBS when you want X to point to the register page. - In your 'RTI' ISR, you use the instruction BSET TFLG2,X,%01000000 to clear the RTIF bit. This instruction WILL clear the RTIF, but as a side-effect of the read-modify-write mechanisim used by the BSET instruction, you will wind up clearing any other flag bit that is set in TFLG2. The BSET instruction works internally like this: the location specified by the first operand (TFLG2 in this case) is read, the value read is ORed with the mask operand you specify, and the result of the OR operation is written back to the same address (TFLG2). If you think this through, and recognize that bits in TFLG2 are RESET when a 1-bit is written to them, you will come to see that any bit set in TFLG2 will be cleared after the BSET instruction is executed. Since you are only using the RTI interrupt, the BSET as you have coded it will not have any adverse effects, but if you later decide to utilize the other interrupt sources that TFLG2 annunciates, the BSET in your RTI routine is going to cause intermittent, difficult-to-track problems. The solution to this problem is quite simple. Replace the BSET instruction with 'BCLR TFLG2,X,%10111111'. This at first glance appears to be a bit odd, but again, if you consider how the BCLR instruction works internally, and the nature of the clearing mechanisim used by TFLG2, the BCLR instruction I show above does the job. Here's how it works: Upon entry to the 'RTI' ISR, bit 6 of TFLG2 (RTIF) will be set. When the BCLR instruction is executed, TFLG2 is read (the value will be %x1xxxxxx x=unknown). The value read from TFLG2 is ANDed with the 1's compliment (inverted) value of the mask you specify - in this case, %10111111 inverted is % 01000000. The result of this AND operation will be %01000000, assuming RTIF is set. This value is then written to TFLG2, which has the result of clearing RTIF but leaving all the other bits unchanged. If, by some odd chance RTIF was not set, the result of the AND operation will be %00000000, which will leave TFLG2 unchanged. Using BSET instead of BCLR to clear flag-register bits is a common mistake made by beginning HC11 programmers. - The SEI instruction at the start of your 'RTI' ISR is unnecessary - the HC11 interrupt service logic automatically sets the interrupt- disable bit when an interrupt is serviced. The I-flag in the status register will be restored to its original state when it is popped off the stack by the RTI instruction. - If I understand what you are trying to do in your RTI routine correctly, it appears as if you wish to iterate through a LED control table, loading one element from the table and storing it to the LED control port every time RTICNT counts down to 0. In this routine, you make numerous references to non-symbolic addresses and constants - this is not very good practice. You could make your RTI LED-control routine truly flexible by making a few simple changes. First, declare these variables at the start of your code: LISTST EQU $3500 ;Start of active LED control table LISTEND EQU $3502 ;End of active LED control table +1 LISTPTR EQU $3504 ;Current location in control table RTICNT EQU $3506 ;RTI delay counter; LED pacing In your main code, initialize these variables to the start and end of the LED control table you want to use: LDD #LIST ;Set start-of-table address STD LISTST STD LISTPTR ;Also init table pointer LDD #LISTEND ;Set end-of-table address STD LISTEND When you wish to 'activate' a different LED control table, say, when a different button is pressed, all you have to do is repeat the code above, substituting the appropriate start and end of table addresses for the ones shown above (e.g. LIST1/LIST1END, LIST2/LIST2END, etc.) In your RTI ISR, iterate through the active LED control table like this: RTI LDX #REGBS ;Point to control registers BCLR TFLG2,X,%10111111 ;Clear RTIF DEC RTICNT ;Decrement delay BNE RTIX ;Exit if delay not complete LDY LISTPTR ;Get current list pointer INY ;Point to next element CPY LISTEND ;End of list ? BLO RTI1 ; No, continue LDY LISTST ; Yes, reset to start of list RTI1 STY LISTPTR ;Save updated list pointer LDAA 0,Y ;Get control byte from list STAA PORTA,X ;Write to LED control port LDAA #80 ;Reset delay count STAA RTICNT ; RTIX RTI ;Exit - One last note. It appears as if the code starting at label 'CONT' up through to the start of your RTI ISR is not used for anything - it is never referenced. I assume this is an alternative test routine you wrote - Am I correct? Hope this helps you out. -- Mark |
