;--------------------------------------------- ; Demonstration of doing three things in sequence: ; ; 1. Rotate the output of a MCP23017 chip (with LEDs on the 16 outputs) ; 2. Read the time on a DS1307 I2C clock chip ; 3. Show the time on a 8-digit 7-segment display which has a MAX7219 chip on it ; using SPI ;--------------------------------------------- jmp begin ; skip past our variables ;--------------------------------------------- ; I2C stuff ;--------------------------------------------- ;--------------------------------------------- ; DS1307 stuff ;--------------------------------------------- CLOCK_PORT = $68 ; DS1307 is on I2C port 0x68 failure_message string "Got NAK\n" select_register_message dfb $00 ; set to register $00 read_time_work BLK 7 ; 7-byte workarea for reading time ;--------------------------------------------- ; MCP23017 registers ;--------------------------------------------- IODIRA = $00 ; IO direction (0 = output, 1 = input (Default)) IOCON = $0A ; IO Configuration: bank/mirror/seqop/disslw/haen/odr/intpol/notimp GPIOA = $12 ; Port value. Write to change, read to obtain value ; ; Change this depending on how you set up the address jumpers. Value $20 to $27 ; - I had all mine set to high (+5V) ; MCP23017_PORT = $27 ; MCP23017 is on I2C port 0x27 ; register value A value B io_configuration_message dfb IOCON, %00100000, %00100000 ; byte mode (not sequential) io_direction_message dfb IODIRA, $0, $0 ; 1 = input, 0 = output io_output_message dfb GPIOA, $22, $00 ; a pattern to show on the LEDs ;--------------------------------------------- ; SPI stuff: MAX7219 registers ;--------------------------------------------- MAX7219_REG_NOOP = $00 ; No operation - used for cascading multiple chips MAX7219_REG_DIGIT0 = $01 ; Write to digit 1 MAX7219_REG_DIGIT1 = $02 ; Write to digit 2 MAX7219_REG_DIGIT2 = $03 ; Write to digit 3 MAX7219_REG_DIGIT3 = $04 ; Write to digit 4 MAX7219_REG_DIGIT4 = $05 ; Write to digit 5 MAX7219_REG_DIGIT5 = $06 ; Write to digit 6 MAX7219_REG_DIGIT6 = $07 ; Write to digit 7 MAX7219_REG_DIGIT7 = $08 ; Write to digit 8 MAX7219_REG_DECODEMODE = $09 ; Decode mode for each digit: 1 = decode, 0 = no decode (one bit per digit) MAX7219_REG_INTENSITY = $0A ; Intensity: 0x00 to 0x0F MAX7219_REG_SCANLIMIT = $0B ; Scan limit: 0x00 to 0x07 - how many digits to display (ie. 1 to 8) MAX7219_REG_SHUTDOWN = $0C ; Shutdown: 0x00 = do not display, 0x01 = display MAX7219_REG_DISPLAYTEST = $0F ; Display test: 0x00 = normal, 0x01 = display all segments ; ; jmp for out-of-range branches ; i2c_failureJ jmp i2c_failure ;--------------------------------------------- ; begin code ;--------------------------------------------- begin: ; ; SPI initialization ; lda #0 ; mode 0 SPI jsr spi_init lda #MAX7219_REG_SCANLIMIT ; show 6 digits ldx #5 jsr spi_send_two_bytes lda #MAX7219_REG_DECODEMODE ; use digits (not bit patterns) ldx #$FF jsr spi_send_two_bytes lda #MAX7219_REG_DISPLAYTEST ; no display test ldx #0 jsr spi_send_two_bytes lda #MAX7219_REG_INTENSITY ; character intensity: range: 0 to 15 ldx #7 jsr spi_send_two_bytes lda #MAX7219_REG_SHUTDOWN ; not in shutdown mode (ie. start it up) ldx #1 jsr spi_send_two_bytes ; ; I2C initialization ; jsr i2c_init ; ; configuration of MCP23017 ; lda #io_configuration_message sta VALUE+1 ldy #3 lda #MCP23017_PORT jsr i2c_send bcc i2c_failureJ ; ; Set ports to output on MCP23017 ; lda #io_direction_message sta VALUE+1 ldy #3 lda #MCP23017_PORT jsr i2c_send bcc i2c_failureJ display_loop: jsr serial_available cmp #'C'-$40 ; ctrl+C? bne loop_no_abort rts ; we are done! loop_no_abort: ; ; show a pattern on the LEDs using the MCP23017 ; lda #io_output_message sta VALUE+1 ldy #3 lda #MCP23017_PORT jsr i2c_send bcc i2c_failureJ ; ; ripple pattern by rotating it ; lda io_output_message+2 ror a rol io_output_message+1 rol io_output_message+2 ; ; now tell the DS1307 clock to go to register zero ; lda #select_register_message sta VALUE+1 ldy #1 lda #CLOCK_PORT ; DS1307 port jsr i2c_send bcc i2c_failure ; ; now read 7 DS1307 registers ; lda #read_time_work sta VALUE+1 ldy #7 lda #CLOCK_PORT ; DS1307 port jsr i2c_receive bcc i2c_failure ; ; Now show the time using the MAX7219 via SPI ; lda read_time_work+2 ; hour ror A ; rotate right 4 times to get high-order digit ror A ror A ror A and #$0F tax lda #6 jsr spi_send_two_bytes lda read_time_work+2 ; hour and #$0F tax lda #5 jsr spi_send_two_bytes lda read_time_work+1 ; minute ror A ; rotate right 4 times to get high-order digit ror A ror A ror A and #$0F tax lda #4 jsr spi_send_two_bytes lda read_time_work+1 ; minute and #$0F tax lda #3 jsr spi_send_two_bytes lda read_time_work+0 ; second ror A ; rotate right 4 times to get high-order digit ror A ror A ror A and #$0F tax lda #2 jsr spi_send_two_bytes lda read_time_work+0 ; second and #$0F tax lda #1 jsr spi_send_two_bytes ; ; wait briefly ; loop_delay: ldx #<400 ldy #>400 jsr delay jmp display_loop i2c_failure: lda #failure_message jsr print jmp loop_delay