\ 2006-06-28 EW adv_03.fs --- Thermometer
\
\ i2c Bus am R8C
\ P1.0 -- SCL
\ P1.1 -- SDA
\ am Bus:
\ PCF8574 (8bit IO), 7-bit Adresse: $20
\ LM75 (Thermometer, 9-bit signed, 7-bit Adresse: $4f

rom

include SMBus.fs

$9e   Constant i2c_addr_lm75

: get.T ( -- xh xl )
    $00                     \ ControlByte
    1 i2c_addr_lm75 NB>i2c  \ verschicken
    2 i2c_addr_lm75 NB<i2c  \ 2 Byte lesen
;

: decode.T ( xh xl -- T*10 )
    $80 and                 \ die ungueltigen Bits loeschen
    swap                    \ xh nach oben holen
    8 lshift                \ xh << 8
    +                       \ == (xh << 8) + ( xl & 0x80)
    5 128 */                \ == T*10
; 

\ _always_ display sign '+' or '-'
: sign! 0 < IF 45 ELSE 43 ENDIF hold ;

\ format T for display (type or lcdtype)
: format.T ( T*10 -- )
    dup >R                  \ store copy for sign
    abs s>d                 \ remove sign, make double
    \ 1 digit, "." 2digits sign_always
    \ Numbers >= 1000 are truncated in the high digits!!!
    <# # 46 hold # # R> sign! #> \ == "%+5.1f"
;

\ write string to lcd position col (0..15) row (0..1)
\ with next lcdtype    
: lcdpos ( row col -- )
    swap $40 * + $80 + lcdctrl! &1 ms ;

: thermometer
    lcdpage
    BEGIN
	0 5 lcdpos
	get.T decode.T format.T lcdtype
	250 ms
    key? UNTIL
;

ram