Juha Tuomi wrote:
>
> Wagner and others,
>
> Sorry that my question was not accurate.
> I have 16-bit value from timer3 (PIC17C43). It can be something between 1Eh...
1700h. Lets say 0...270Fh for sure. I have to convert that value to ascii-number
s, because the value will be displayed with a LCD module (that needs ascii-chara
cters, of course) and will be transmitted to a pc (RS232). I have 4 digits for d
isplay and transmit. So, the 16-bit value needs to be converted to four ascii-nu
mbers. The timer value can't be greater than 270Fh, that's  9999 in ascii. This
is the conversion I need!
>
> Thanks in advance
> Juha


Ok, then you need to do two steps:

1) Convert Hexadecimal to Decimal (BCD)
2) Convert (BCD) Binary Coded Decimal to ASCII

Lets call your 16 bits as TIM3
Lets call your 4 BCD's as BCD#1,BCD#2,BCD#3,BCD#4
BCD#1 is the most significant digit

The first step is done in several ways.

Lets see one way that get directly 4 digits with
values = 09 and below, not exactly bcd.

You can divide the 16 bits in three steps
a) Divide TIM3 / 03E8 = BCD#1, rest back to TIM3
b) Divide TIM3 / 0064 = BCD#2, rest back to TIM3
c) Divide TIM3 / 000A = BCD#3, rest is BCD#4

How you do the division of TIM3/03E8?
Just subtract TIM3 - 03E8 until it the result
goes below zero, so it generates "carry", then
add 03E8 to have the rest positive.
The quantity of subtractions with a positive
rest lower than 03E8 is the BCD#1.
The same for the others, 0064 and 000A.

Now you take BCD#1, and OR 30h, you have the
decimal ASCII value from 30h to 39h (0-9), do
it to BCD#2,3,4.

That simply division routine is not pretty and
not the faster one, but it works for your delight.
It can take as long as 36 subtraction loops, if
the TIM3 = 270Fh.

Remember to check for TIM3=0 before you do the
subtractions, if TIM3 = 0, BCD#n up to BCD#4 would
be also zero, so the division is finished.

Example: TIM3 = 0FA0h will give you 4 subtractions
of 03E8h and the rest will be zero, decimal result
will be 4000.

TIM3 = 0FA8h will give you 4 subtractions of 03E8h,
the rest will be 0008, none to BCD#2 (0064h), none
to BCD#3 (000A), resting to BCD#4, result: 4008d

You may find different solutions, but do this first,
easily you will learn differences between several
division routines.

Wagner