How to implement soft UART ?

[nprao]

Hi

Can any one tell me how to implement soft Uart with some code example or any link.

Thanks

 

[goshka]

soft uart source code

Half Duplex Compact Software UART - Source Atmel
ftp://www.atmel.com/pub/atmel/avr305.asm

 

[brmadhukar]

uart source code soft

Hi,
Soft UART is meaningful only for very low baud rates. (<19,200).
The theory is
Sample the RX at 3/5/7 times the baud rate.
Align the data such that 3/5/7 reperesents one data bit.
Take the center (2nd/3rd/4th) bit at the RX data. If you use higher sampling you may be able to handle large short term baudrate variations.

Hope this helps.
B R M

 

[nprao]

data path of uart

Hi brmadhukar

Can please post here some code example or email me the code if you have email: nprao4@hotmail.com

Thanks

 

[rob13572468]

soft-uart

Hi,
Soft UART is meaningful only for very low baud rates. (<19,200).
The theory is
Sample the RX at 3/5/7 times the baud rate.
Align the data such that 3/5/7 reperesents one data bit.
Take the center (2nd/3rd/4th) bit at the RX data. If you use higher sampling you may be able to handle large short term baudrate variations.

Hope this helps.
B R M

it is quite possible to implement higher data rates in a software uart including 115K and above. I agree that with higher baud rates its going to be better (and easier) to use a hardware uart, but its still a matter of designing within the limits of the controller. for example i wrote firmware for an atmel that runs at 115K with only one sample point for the bit but the serial data path is only a few cm. obviously if the data needs to travel further or be in a noisier environment then more sampling will be needed.

 

[bobcat1]

atmega asm soft uart

Look at IAR site appnote for micro w*w.iar.com

You will find an app not for soft uart in C language

Best

Bobi