;Jeff Mucha ;pic microcontroler code for exercising multi color LEDs in the probe tip ;Porta bits 0 1 2 3 4 are inputs where active low switches are attached. ;proper debouncing is required. ;Portb bit 1 is bit banging SCL on the I2C interface ;Portb bit 2 is bit banging SDA on the I2C interface ;Portb bit 0 is used to detect a probe being attached ;Portb bit 3 is used to turn on and off the trace color LED ;external clock is devided by 4 to provide internal clock most all instructions take 1 internal cycle ;//////////////// ;This code Generates an I2C interface to control multi-element LEDs ; list p=16f84 radix hex #define SCL 1 ;I2C port pin number #define SDA 2 ;I2C port pin number #define tri_wr b'00001001' ;set the SDA and SCL as outputs #define tri_re b'00001101' ;set SDA as an input ;--------------------------------------------------; ;equates ;--------------------------------------------------; pc equ 0x02 f equ 0x01 porta equ 0x05 portb equ 0x06 status equ 0x03 counter equ 0x0c ;general purpose counter table_val equ 0x0d table_off equ 0x0e counter2 equ 0x0f ;general purpose counter2 address_reg equ 0x10 ; address byte inst_reg equ 0x11 ; instruction byte scratch_reg equ 0x12 ; scratch data_blue equ 0x13 ; data byte data_green equ 0x14 ; data byte data_red equ 0x15 ; data byte stord_red equ 0x16 ; data byte stord_green equ 0x17 ; data byte stord_blue equ 0x18 ; data byte reset_reg equ 0x19 ; reset byte, b0 = idle routine ;--------------------------------------------------; ;main program ;--------------------------------------------------; org 0x000 start movlw tri_wr ;set i2c as outputs tris portb movlw 0xff ;set port a all inputs tris porta movlw b'00000000' movwf table_val ;reset variables movwf counter movwf reset_reg movlw b'00000110' movwf portb movlw b'01001000' ; address byte movwf address_reg movlw b'00000101' ; instruction byte write red movwf inst_reg movlw b'00101100' ; init data movwf data_blue movlw b'00100011' ; init data movwf data_green movlw b'00011010' ; init data movwf data_red call wr_i2c ; reset everything bsf portb,7 ; trigger nop bcf portb,7 goto scan ;--------------------------------------------------------- ; lookup table ;-------------------------------------------------------- table addwf pc,f ;blue lookup table nop retlw b'00011010' ; green retlw b'00111111' retlw b'00101100' retlw b'00111011' ; Yellow retlw b'00111111' retlw b'00101100' retlw b'00011010' ; blue retlw b'00111011' retlw b'00111111' retlw b'00111111' ; purple retlw b'00100011' retlw b'00111111' ;---------------------------------------------------------- ;Scan the input pins ;---------------------------------------------------------- scan movlw b'00011111' ;port a bits 0,1,2,3 set high means no buttons pushed subwf porta,w ;compare w to port a using the subtract and then z flag check btfss status,2 goto select btfss portb,0 call delay btfsc portb,3 ;c call idle btfsc reset_reg,0 ; skip instruction if bit clear btfsc portb,3 ;c ; skip if clear goto scan call wr_i2c bcf reset_reg,0 goto scan select btfss porta,0 call setr btfss porta,1 call setg btfss porta,2 call setb btfss porta,3 call set_tbl goto scan ;---------------------------------------------- ; color increment routines ;---------------------------------------------- setr incf data_red,f call wr_i2c testr btfss porta,0 goto testr goto scan setg incf data_green,f call wr_i2c testg btfss porta,1 goto testg goto scan setb incf data_blue,f call wr_i2c testb btfss porta,2 goto testb goto scan ;--------------------------------------------------- ; Delay routine ;--------------------------------------------------- delay movlw b'11111111' ;set conter to highest value movwf counter movwf counter2 dloop movwf counter2 dloop2 decfsz counter2,f goto dloop2 decfsz counter,f goto dloop call wr_i2c return ;--------------------------------------------------- ; lookup table routine ;------------------------------------------ set_tbl incf table_val,f ;increment color table movfw table_val ;set table value for offset call table movwf data_red incf table_val,f ;increment color table movfw table_val ;set table value for offset call table movwf data_green incf table_val,f ;increment color table movfw table_val ;set table value for offset call table movwf data_blue call wr_i2c movlw d'12' ;set to the number of entrys in the table subwf table_val,w ;compare w to table value using the subtract and then z flag check btfsc status,2 clrf table_val test_tb btfss porta,3 goto test_tb return ;------------------------------------------ ; Routine for setting the inactive color ;--------------------------------------- idle movf data_red,w movwf stord_red movf data_green,w movwf stord_green movf data_blue,w movwf stord_blue movlw b'00101100' ; idle data movwf data_blue movlw b'00100011' ; idle data movwf data_green movlw b'00011111' ; idel data movwf data_red call wr_i2c movf stord_red,w movwf data_red movf stord_green,w movwf data_green movf stord_blue,w movwf data_blue bsf reset_reg,0 return ; old code stop nop goto stop ;------------------------------------------------------------ ; Write Byte Serial routine ;------------------------------------------------------------ ; Set the inst_reg and data_reg to set the value for the dac ; to be set wr_i2c movlw tri_wr ; set tris register for writing tris portb bcf portb,SDA ; Start bit movf address_reg,w movwf scratch_reg call byte movf inst_reg,w movwf scratch_reg call byte movf data_blue,w movwf scratch_reg call byte movf data_green,w movwf scratch_reg call byte movf data_red,w movwf scratch_reg call byte bsf portb,SCL nop bsf portb,SDA ; Stop bit return byte movlw 0x08 ; set counter to 8 bits for shifting movwf counter loop1 bcf portb,SCL ; set clock low for setup time rlf scratch_reg,f ; rotate data through carry btfsc status,0 ; test the carry bit bsf portb,SDA ; set SFD high btfss status,0 bcf portb,SDA ; set SDA low nop bsf portb,SCL decfsz counter goto loop1 ak1 bcf portb,SCL ; set clock line low movlw tri_re ; set data line tristate tris portb bsf portb,SCL ; set clock line high nop ; test ack bit bcf portb,SCL ; set clock line low movlw tri_wr ; set data line write tris portb return end