$MODDE2

org 0000H
    ljmp myprogram

Load32 MAC
mov %0 + 0, #low(%1 % 10000H)
mov %0 + 1, #high(%1 % 10000H)
mov %0 + 2, #low(%1 / 10000H)
mov %0 + 3, #high(%1 / 10000H)
ENDMAC

SCLK EQU P1.1
MOSI EQU P1.2
MISO EQU P1.3
CE_ADC EQU P1.4



cseg
Name1:
    DB 'T:      Celsius'
    DB 0

Name2:
    DB '              '
    DB 0

Wait40us:
    mov R5, #149
X1:
    djnz R5, X1 ; 3 machine cycles-> 3*90ns*149=40us
    ret

INIT_SPI:
    orl P1MOD, #00010110b ; Set SCLK, MOSI, CE_ADC as outputs
    anl P1MOD, #11110111b ; Set MISO as input
    clr SCLK ; Mode 0,0 default
ret

Delay:
    mov R3, #20
    Delay_loop:
    djnz R3, Delay_loop
    ret

DO_SPI_G:
    push acc
    mov R1, #0 ; Received byte stored in R1
    mov R2, #8 ; Loop counter (8-bits)

DO_SPI_G_LOOP:
    mov a, R0 ; Byte to write is in R0
    rlc a ; Carry flag has bit to write
    mov R0, a
    mov MOSI, c
    setb SCLK ; Transmit
    mov c, MISO ; Read received bit
    mov a, R1 ; Save received bit in R1
    rlc a
    mov R1, a
    clr SCLK
    djnz R2, DO_SPI_G_LOOP
    pop acc
    ret


LCD_command:
    mov LCD_DATA, A
    clr LCD_RS
    setb LCD_EN
    clr LCD_EN
    ljmp Wait40us
ret

LCD_put:
    mov LCD_DATA, A
    setb LCD_RS
    setb LCD_EN
    clr LCD_EN
    ljmp Wait40us
ret

LCDON:
    setb LCD_ON
    lcall Wait40us
    mov LCD_MOD, #0xff ; Use LCD_DATA as output port
    clr LCD_RW ; Only writing to the LCD in this code.
    mov a, #0CH ; Display on command
    lcall LCD_command
    mov a, #38H ; 8-bits interface, 2 lines, 5x7 characters
    lcall LCD_command
    mov a, #01H ; Clear screen (Warning, very slow command!)
    lcall LCD_command
    ; Delay loop needed for 'clear screen'
    ; command above (1.6ms at least!)
    mov R1, #40

    clr_loop:
    lcall Wait40us
    djnz R1, Clr_loop
    ret


send_msg:
    clr a
    movc a, @a+dptr
    jz second
    inc dptr
    lcall LCD_put
    sjmp send_msg
    ret

send_msg2:
    clr a
    movc a, @a+dptr
    jz forever
    inc dptr
    lcall LCD_put
    sjmp send_msg2
    ret

myprogram:
    mov SP, #7FH
    mov LEDRA, #0 ; Turn off all LEDs
    mov LEDRB, #0
    mov LEDRC, #0
    mov LEDG, #0
    lcall INIT_SPI
    lcall LCDON

    mov a,#80H
    lcall LCD_command
    mov dptr, #Name1
    lcall send_msg

second:
    mov a, #0C0H
    lcall LCD_command
    mov dptr, #Name2
    lcall send_msg2

forever:
    clr CE_ADC
    mov R0, #00000001B ; Start bit:1, Single:1, D2: 0
    lcall DO_SPI_G


Read_Temp:
    mov R0, #10000000B ; Read channel 0; D1 (bit 7): 0, D0 (bit 6):0
    lcall DO_SPI_G
    mov a, R1 ; R1 contains bits 8 to 9
    anl a, #03H
    mov LEDRB, a
    mov R7, a
    mov R0, #55H ; It doesn't matter what we transmit...
    lcall DO_SPI_G
    mov LEDRA, R1 ; R1 contains bits 0 to 7
    mov a,R1
    mov R6,a
    lcall display_temp
    setb CE_ADC
    lcall Delay

    ljmp forever

display_temp:
    mov a, #83H
    lcall LCD_command
    lcall ADC_to_Celcius
    ret

ADC_to_Celcius:
; [R7,R6] has the 10-bit value
; from the converter
mov x+0, R6
mov x+1, R7
mov x+2, #0
mov x+3, #0
Load32 (y, 500000)
lcall mul32
Load32 (y, 1024)
lcall div32
Load32 (y, 50000)
lcall sub32
lcall hex2bcd
; Display temperature in LCD
;*******************************NEED TO FIGURE OUT THE SIGFIGS
;most sig digit
mov a, bcd+2
swap a
anl a, #0FH
add a, #30h
orl a, #'0'
lcall LCD_put
;2nd most sig
mov a, bcd+2
anl a, #0FH
add a, #30h
orl a, #'0'
lcall LCD_put
; Decimal point
mov a, #'.'
lcall LCD_put
; 3rd
mov a, bcd+1
swap a
anl a, #0FH
add a, #30h
orl a, #'0'
lcall LCD_put

ret

; start here

$include(math32.asm)
END