terom@18: ;;
terom@18: ;; Driving 7-segment LED displays over SPI
terom@18: ;;
terom@18: 
terom@18: ; Output Enable control
terom@17: .equ LED7_DDR    = DDRB
terom@17: .equ LED7_PORT   = PORTB
terom@17: .equ LED7_OE     = PORTB1                ; Output Enable (Low)
terom@17: 
terom@18: ; Font for 7-segment display
terom@18: ; Includes decimal digits 0-9, hexadecimal digits A-F, and some special chars
terom@17: LED7_Font:
terom@17: .db     0b00111111, 0b00000110      ; 0, 1
terom@17: .db     0b01011011, 0b01001111      ; 2, 3
terom@17: .db     0b01100110, 0b01101101      ; 4, 5
terom@17: .db     0b01111101, 0b00000111      ; 6, 7
terom@17: .db     0b01111111, 0b01100111      ; 8, 9
terom@17: .db     0b01110111, 0b01111100      ; A, b
terom@17: .db     0b00111001, 0b01011110      ; C, d
terom@17: .db     0b01111001, 0b01110001      ; E, f
terom@17: .db     0b10000000, 0b00000000      ; ., 
terom@17: 
terom@23: .equ LED7_0     = 0
terom@23: .equ LED7_1     = 1
terom@23: .equ LED7_2     = 2
terom@23: .equ LED7_3     = 3
terom@23: .equ LED7_4     = 4
terom@23: .equ LED7_5     = 5
terom@23: .equ LED7_6     = 6
terom@23: .equ LED7_7     = 7
terom@23: .equ LED7_8     = 8
terom@23: .equ LED7_9     = 9
terom@23: .equ LED7_A     = 10
terom@23: .equ LED7_B     = 11
terom@23: .equ LED7_C     = 12
terom@23: .equ LED7_D     = 13
terom@23: .equ LED7_E     = 14
terom@23: .equ LED7_F     = 15
terom@23: .equ LED7_DOT   = 16
terom@23: .equ LED7_EMPTY = 17
terom@17: 
terom@26: ; LEDs are on beginning of SPI universe
terom@26: .set led7_buffer = spi_outbuf + 0
terom@17: 
terom@17: ;; Initialize LCD to empty, and enable
terom@17: LED7_Init:
terom@17:     ; Setup ENable port
terom@17:         sbi         LED7_PORT, LED7_OE    ; Disabled (Low)
terom@17:         sbi         LED7_DDR, LED7_OE     ; Out
terom@23:     
terom@23:     ; Initialize buffer
terom@30:         ldi         r16, 0b01000000
terom@23:         sts         led7_buffer + 0, r16
terom@23:         sts         led7_buffer + 1, r16
terom@17: 
terom@26:     ; Update display
terom@26:         rcall       SPI_SendRecv
terom@17: 
terom@23:     ; Enable output once the initial display has been shifted out
terom@17:         cbi         LED7_PORT, LED7_OE
terom@17: 
terom@17:     ; Done
terom@17:         ret
terom@17: 
terom@23: LED7_LoadChar:
terom@17:         clr         r0, 0
terom@17: 
terom@17:     ; Prep address
terom@17:         ; base addr for font table
terom@23:         ldi         ZH, high(2 * LED7_Font)
terom@23:         ldi         ZL, low(2 * LED7_Font)
terom@17:         
terom@17:         ; offset
terom@23:         add         ZL, r8
terom@17:         adc         ZH, r0
terom@17: 
terom@17:     ; Load char
terom@23:         lpm         r8, Z
terom@23: 
terom@23:     ; Done
terom@23:         ret
terom@25: 
terom@25: ;; Display an 8-bit hexadecimal value on the display
terom@25: ;;  Input: r16
terom@25: LED7_ShowHex:
terom@25:         ; base16
terom@25:         ldi         r17, 16 
terom@25: 
terom@25:         ; 1's
terom@25:         call        div8u
terom@25:         
terom@25:         ; r16 = result, r15 = remainder
terom@25:         mov         r17, r15 
terom@25: 
terom@25:     ; Continue
terom@25:         rjmp        LED7_Show
terom@25: 
terom@25: ;; Display an 8-bit decimal value on the display
terom@25: ;;  Input: r16
terom@25: LED7_ShowDec:
terom@25:         ; base10
terom@25:         ldi         r17, 10
terom@25: 
terom@25:         ; 1's
terom@25:         call        div8u
terom@25:         mov         r8, r15
terom@25: 
terom@25:         ; 10's
terom@25:         call        div8u
terom@25:         mov         r9, r16         ; 100's
terom@25:         
terom@25:         ; 1's from r8
terom@25:         rcall       LED7_LoadChar
terom@25:         mov         r17, r8
terom@25: 
terom@25:         ; 10's from r15
terom@25:         mov         r8, r15
terom@25:         rcall       LED7_LoadChar
terom@25:         mov         r16, r8
terom@25:            
terom@25:         ; Set dots for 100's 
terom@25:         sbrc        r9, 0
terom@25:         ori         r17, 0b10000000 ; +100
terom@25:         sbrc        r9, 1
terom@25:         ori         r16, 0b10000000 ; +200
terom@25: 
terom@25:     ; Continue
terom@25:         rjmp        LED7_ShowRaw
terom@25: 
terom@23: ;; Display a single digit on the display
terom@23: ;;  Input: r16, r17
terom@23: LED7_Show:
terom@23:         mov         r8, r16
terom@23:         rcall       LED7_LoadChar
terom@23:         mov         r16, r8
terom@23: 
terom@25:         mov         r8, r17
terom@23:         rcall       LED7_LoadChar
terom@25:         mov         r17, r8
terom@23:         
terom@17:     ;; Continue
terom@17: 
terom@17: ;; Display a raw segment mask
terom@23: ;;  Input: r16, r17
terom@17: LED7_ShowRaw:
terom@26:     ; Store buffer
terom@23:         sts         led7_buffer + 0, r16
terom@23:         sts         led7_buffer + 1, r17
terom@23: 
terom@26:     ; Update display
terom@30:         rjmp        SPI_Update
terom@17: