Dallas DS1620 Temprature Sensor

Hi everyone,,,

I want to use the DS1620 chip as a thermometer to read the Temp, so I had to operate with the (3-wire mode).
I just need 1 temprature reading so I used the 1 shot mode.

*The first thing I had to access the configuration register by the command (write config 0Ch).
*Then setting the register to be 00000011 (CPU, 1SHOT) are set.
*After that I issued the command (start convert T EEh)
*The last command is (read temprature AAh)

to see the thing clearly I used three switches, one for DQ, another for CLK and the third for RST.

My sequence to write the instructions was:

1- Rst is low
2- CLK is high
3- Rst is high
4- CLK is low
5- setting DQ for the LSB of the instruction
6- CLK is high
7- repeating (4, 5, 6) for the remaining bits of the instruction
8- Rst is low then High (Toggling)
9- Next instruction.

But I cant get any thing in DQ in read mode when i start the CLK does anyone know why??

Many Thanks

Does this Chip need fast switching? I used manual switches to write data and pulse the clock.
I hope someone can give me useful hints.

Thanks

I wonder if you may be overlooking some important timing considerations?

abees81 said:

Does this Chip need fast switching? I used manual switches to write data and pulse the clock.
I hope someone can give me useful hints.

Thanks

Click to expand...

Did you debounce your switches? A mechanical switch will create several transitions before settling after the switch is actuated. Google "switch debouncing".

Thanks guys for replying.
Well I got it working using uC, so maybe I had timing as well as mechanical problems.