can we use uart to communicate wire one wire device

[HARI krishna]

Posted on June 15, 2017 at 08:08

Hi all,

I have DS18B20 sensor which works on the one wire protocol & it was interfaced to STM32F030C8T6 controller.

But it was failed to communicate(respond) with the device over UART2.Below is the uart to device connection Fig.

I am using 3.3V for to power the device and 2.2K pull-up on the bus(as mentioned in the datasheet).

How to Generate reset signal (480us low on the bus) on the uart pins for one wired device.

please help me on this issue

UART Connection to one wire Bus :

[HARI krishna]

Posted on June 16, 2017 at 12:41

Kindly waiting for valuable replies,

Can we use gpio to implement one wire interface?

[Uwe Bonnes]

Posted on June 19, 2017 at 13:40

As the ST uart pind can be put into open-drain mode, you can connect the OW device direct to TX with an appropriate pullup provided. Parallel connect RX or with newer the UART revision as found in the F0, use half duplex mode  so no external RX pin is needed. Have a look at Maxim application note AN126.

[Tesla DeLorean]

Posted on June 19, 2017 at 13:52

Certainly not going to be able to use the USART to implement the 1-wire protocol. Review the protocol and use the RX pin without the other circuitry.

[Andrew Neil]

Posted on October 20, 2017 at 19:28

Maxim have an App Note on how to do this.

They also have various 'bridge' chips ...