i2cslave.lst

ADuc812的例程

I2CSLAVE                                                                                                      PAGE 1

                       1    ;======================================================================
                       2    ;
                       3    ; Author        : ADI - Apps              www.analog.com/MicroConverter
                       4    ;
                       5    ; Date          : Oct 2000
                       6    ;
                       7    ; File          : i2cslave.asm
                       8    ;
                       9    ; Hardware      : ADuC812 (commented out = ADuC816/ADuC824)
                      10    ;
                      11    ; Description   : Code for a slave in an I2C system. This code will
                      12    ;               continuously receive and transmit a byte over the I2C
                      13    ;               interface, then send the received byte out the UART, 
                      14    ;               then check if a character had been entered in the UART.
                      15    ;               If so, it will send the ASCII value of the character
                      16    ;               entered to the slave, the next time it transmits a byte.
                      17    ;
                      18    ; Reference     : Tech Note, uC001: "MicroConverter I2C Compatible
                      19    ;               Interface" find it at www.analog.com/microconverter
                      20    ;
                      21    ;======================================================================
                      22    
                      23    $MOD812                         ; use ADuC812 & 8052 predefined symbols
                      24    ;$MOD816
                      25    ;$MOD824
                      26    
                      27    
                      28    ;____________________________________________________________________
                      29                                       ; DEFINE VARIABLES IN INTERNAL RAM
                      30    
  0030                31    BYTECNT         DATA    30h     ; byte counter for I2C routines
  0031                32    INPUT           DATA    31h     ; data recieved from master
  0032                33    OUTPUT          DATA    32h     ; data to be transmitted to master
                      34    
  0000                35    GO              BIT     00h     ; flag for all the interrupts
  0001                36    FIRST           BIT     01h     ; flag for recieve mode interrupt
  0002                37    TR              BIT     02h     ; flag for transmit mode interrupt
                      38    
  00B4                39    LED             EQU     P3.4    ; P3.4 drives the LED on eval board
                      40    
                      41    ;____________________________________________________________________
                      42                                                      ; BEGINNING OF CODE
----                  43    CSEG
0000                  44    ORG 0000h
0000 020060           45            JMP MAIN
                      46    ;____________________________________________________________________
                      47                                                               ; INT0 ISR
0003                  48    ORG 0003h
0003 0532             49            INC     OUTPUT
0005 32               50            RETI
                      51    ;____________________________________________________________________
                      52                                                                ; I2C ISR
003B                  53    ORG 003Bh  
                      54    
003B 20E90D           55            JB      I2CTX,TRANSMIT  ; if slave-transmitter get data ready
                      56    
003E                  57    RECEIVE:
003E C202             58            CLR     TR              ; FLAG to indicate that this time
I2CSLAVE                                                                                                      PAGE 2

                      59                                    ; we were receiving (not trans'ting)
0040 20010F           60            JB      FIRST, ENDINT1  ; no need to store the address
0043 D200             61            SETB    GO              ; reception complete 
0045 859A31           62            MOV     INPUT, I2CDAT   ; store data recieved in INPUT
0048 020052           63            JMP     ENDINT1         ; ERROR => end interrupt
                      64    
004B                  65    TRANSMIT:
004B D202             66            SETB    TR              ; FLAG to indicate that this time
                      67                                    ; we were transmitting (not receiving)
004D D200             68            SETB    GO              ; transmission complete
004F 85329A           69            MOV     I2CDAT,OUTPUT   ; move data to be transmitted into I2CDAT
                      70    ;        JMP     ENDINT2         ; Note: On the ADuC824/816 the read or
                      71                                    ;       write of I2CDAT register 
                      72                                    ;       automatically clears i2ci. If
                      73                                    ;       I2CI is cleared twice then the
                      74                                    ;       microconverter will hang.)
                      75    
0052                  76    ENDINT1:
0052 C2E8             77            CLR     I2CI            ; clear I2C interrupt bit (812 only)
0054                  78    ENDINT2:
0054 C201             79            CLR     FIRST           ; address has already been recieved
                      80    
0056 32               81            RETI
                      82    
                      83    
                      84    ;____________________________________________________________________
                      85                                                           ; MAIN PROGRAM
0060                  86    ORG 0060h
0060                  87    MAIN:
                      88    
                      89    ; configure the UART ADuC812
0060 759852           90            MOV     SCON,#52h       ; configure UART for 9600baud..
0063 758920           91            MOV     TMOD,#20h       ; ..assuming 11.0592MHz crystal
0066 758DFD           92            MOV     TH1,#-3
0069 D28E             93            SETB    TR1
                      94    
                      95    ; configure the UART ADuC824/ADuC816
                      96    ;        MOV     RCAP2H,#0FFh   ; config UART for 9830baud
                      97    ;        MOV     RCAP2L,#-5     ; (close enough to 9600baud)
                      98    ;        MOV     TH2,#0FFh
                      99    ;        MOV     TL2,#-5
                     100    ;        MOV     SCON,#52h
                     101    ;        MOV     T2CON,#34h
                     102    
                     103    ;configure and enable interrupts
006B 75A901          104            MOV     IE2,#01h        ; enable I2C interrupt
                     105    ;        MOV     IEIP2,#01h      ; enable I2C interrupt
006E D2A8            106            SETB    EX0             ; enable INT0
0070 D288            107            SETB    IT0             ; INT0 edge triggered
0072 D2AF            108            SETB    EA              ; allow all the interrupts
                     109    
                     110    
                     111    ;initialise settings
0074 759B44          112            MOV     I2CADD,#044h    ; slave address is 44h
0077 75E800          113            MOV     I2CCON,#00h     ; slave mode
007A C200            114            CLR     GO              ; clear flag used in the interrupt
                     115    
007C 753200          116            MOV     OUTPUT,#0       ; TX 0 as default
I2CSLAVE                                                                                                      PAGE 3

007F D2B4            117            SETB    LED
                     118    
0081                 119    RESET:  
0081 D201            120            SETB    FIRST           ; first byte recieved will be the