Serial out

Kiwi

hello,

Example: say that you have a 8bits memory space, that contains the value #255. I want to display this number on a LCD or Hyperterminal. That would means that i first have to·send the asci value of ·#2, then #5,and· #5.

But how can i implement a division instruction or routine·to obtain the 2,5,5?

Kurt

Bean

I typically use the "subtraction" method.

Count how many times you can subtract 100 until the value underflows, then add 100 to the value
Count how many times you can subtract 10 until the value underflows, then add 10 to the value
The value left is the units (1's) value.
Bean.

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"SX-Video Display Module" Available Now.

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"A problem well defined, is a problem·half solved."
·

KenM

I also use the method Bean mentioned.

The entire program can be found at

·http://www.parallax.com/sx/contest/contest_door_velocity.asp

;this sub is used to get number of hundreds from the division result
get_bhunds
 inc  bhunds  ;increment bhunds    
 mov  w,source0 ;move 100 decimal into w
 sub  accum0,w ;subtract 100 from accum0
 mov  w,source1 ;move source1 into w
 sb  c  ;skip next line if carry was set
 movsz  w,++source1 ;move into w source1 +1
 sub  accum1,w ;subtract w from accum1
 snb  c  ;skip next line if carry was not set
 jmp  get_bhunds ;jump to get_bhunds
 dec  bhunds  ;decrement bhunds
 mov  w,#$64  ;move $64 (drec 100) into w
 add  accum0,w ;add $64 to accum0
 mov  w,#$00  ;move 0 into w
 mov  temp0,w  ;move w into temp0
 snb  c  ;skip next line if carry was not set
 movsz  w,++temp0 ;move temp0 +1 into w
 add  accum1,w ;add w to accum1 (restore to correct value)
 ret    ;done adding 100 to accum0 and accum1
;now bhunds holds the number of 100's from dividing number of micrseconds into the
;constant value of 1,610,128
 

;now get number of ctens
get_ctens
 inc  ctens  ;increment ctens
 mov  w,source0 ;move source0 into w
 sub  accum0,w ;subtract w from accum0
 snb  c  ;skip if carry not set
 jmp  get_ctens ;jump to get_ctens
 dec  ctens  ;decrement ctens
;ctens now holds the number of 10's after the number of 100's was extracted
 mov  w,#$0a  ;move $0a into w
 add  accum0,w ;add w to accum0
;accum0 now holds number of left over ctens which is the same as the number of ones
 mov  w,accum0   ;move accum0 into w
 mov  ones,w  ;move w into ones
 ret