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Forum Index : Microcontroller and PC projects : TTL to 422 Waveshare

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PhenixRising
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Joined: 07/11/2023
Location: United Kingdom
Posts: 856
Posted: 05:37pm 26 Sep 2024
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Quite like the look (and price) of this

Obviously auto-enabling and I like the isolation and selectable terminating resistor.

Waveshare has an interesting store on AE.  
 
Volhout
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Joined: 05/03/2018
Location: Netherlands
Posts: 4222
Posted: 05:51pm 26 Sep 2024
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Looks nice, but...

1/ It can be powered by 3.3V. I wonder how good that is for an isolated switcher.

2/ some of the datasheet is incorrect. This can not be done with RS422, or they violate the output specification, in which case I would not use the device. Outputs cannot parallel. In RS485 you can since they are disabled when not driven, but RS422 is always ON.



Volhout
Edited 2024-09-27 03:52 by Volhout
PicomiteVGA PETSCII ROBOTS
 
PhenixRising
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Joined: 07/11/2023
Location: United Kingdom
Posts: 856
Posted: 06:13pm 26 Sep 2024
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  Volhout said  Looks nice, but...

1/ It can be powered by 3.3V. I wonder how good that is for an isolated switcher.

2/ some of the datasheet is incorrect. This can not be done with RS422, or they violate the output specification, in which case I would not use the device. Outputs cannot parallel. In RS485 you can since they are disabled when not driven, but RS422 is always ON.



Volhout


That's my point Harm. Lots of newer devices sense the data and auto-enable/disable.

Even their 485 devices only require RX, TX, GND on the TTL side.  
 
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