DS1820 binary

[Transistorman]

anyone know binary table of DS1820 ?

 

[3v0]

The one wire devices follow a protocol that is well documented in their datasheets.

In general you first select the device you want to talk to with MATCHROM or SKIPROM. Then you can communicate with the device.

 

[Transistorman]

The one wire devices follow a protocol that is well documented in their datasheets.

In general you first select the device you want to talk to with MATCHROM or SKIPROM. Then you can communicate with the device.

any asm example ?

 

[ericgibbs]

any asm example ?

hi TT,
The Forum SEARCH is a useful tool...
https://www.electro-tech-online.com/search.php?searchid=571871

 

[Pommie]

You could try this thread.

Mike.

 

[Transistorman]

hi TT,
The Forum SEARCH is a useful tool...
https://www.electro-tech-online.com/search.php?searchid=571871

i dont really understand the datasheet

if 85 c = 0000 0000 1010 1010

and what is the other ?

example : 75 c , 22 c , 35 c , etc

**broken link removed**

 

[Pommie]

What don't you understand? It's just BCD numbers.

Edit, 75 would be 150 converted to BCD, so 0x96.

Mike.

 

[Transistorman]

What don't you understand? It's just BCD numbers.

Edit, 75 would be 150 converted to BCD, so 0x96.

Mike.

ok i understand

but what about the - letter ?

 

[Pommie]

but what about the - letter ?

No idea what you are talking about.

Mike.

 

[Transistorman]

No idea what you are talking about.

Mike.

like -35 c

 

[ericgibbs]

like -35 c

hi,
When the most significant BIT of the READ value is set to 1, it indicates negative temperature value.

 

[Transistorman]

hi,
When the most significant BIT of the READ value is set to 1, it indicates negative temperature value.

does it mean

if 1111 1111 = -

and 0000 0000 = +

if yes

then what is 110 c ?

 

[ericgibbs]

does it mean

if 1111 1111 = -

and 0000 0000 = +

if yes

then what is 110 c ?

hi TT,
Think about it.

the least significant BIT is equal to 0.5C
So 110C = 220decimal which equals hex.........................??????

 

[3v0]

You need to understand 2's compliment numbers.

In 2's comp the leftmost bit is assumed to be negative.
All other bits are positive.

In a 4 bit binary number the bit values are

8 4 2 1

if we choose 2's comp representation they are

-8 4 2 1

So a decimal 1 would be

0001

and a decimal -1 is
11111
because -8 +4 +2 +1 = -1 (we just added the bit values where we had a 1)

a decimal -4 would be
1100
because -8 +4 = -4

Regardless of the number of bits it is always the leftmost bit that is assumed to be negative.

But as Eric said in the case of this sensor the rightmost bit is worth .5 rather then 1

.

 

[Transistorman]

hi

i made a random number

if 0096h = 150 / 2 = 75c

then 00c8h = 200 / 2 = 100c

is it right ?

 

[ericgibbs]

hi

i made a random number

if 0096h = 150 / 2 = 75c

then 00c8h = 200 / 2 = 100c

is it right ?

Its close enough.

 

[Transistorman]

Its close enough.

why do you say " close enough " ?

 

[ericgibbs]

why do you say " close enough " ?

Its correct, thats what I mean........