Is it possible to connect ports of an UART component to logic gates?

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NeAl_2298636
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Hi,

I tried the connections as below, but it gives a ton of errors. Is it not possible to use the gates with other components?

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odissey1
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necdet,

The single-wire UART communication can be accomplished in Master-Slave configuration. Both UARTs are idling in Rx state. To send message the Master switches to Tx mode, sends message and goes into idle Rx state. The slave receives message, goes into Tx mode, responds, and returns back into idle Rx state. Only Master can initiate communication to avoid collision. This way you can communicate PSoC to PSoC only. Each UART should be connected to in-out pin through bufoe, which direction is controlled by ControlReg.

odissey1

UART_1-wire_01.png

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Bob_Marlowe
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What errors? Easiest to check is always when you provide us with a workspace bundle.

Bob

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Thanks Bob,

Attaching the workspace bundle. Problem is between UART Rx and buffer output connection.

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Of course you may connect Rx to logic gates. But the error message tells that you need an in-out terminal to connect to the buffer. There are times when the input to Rx is undefined. Use a different gate for your Rx.

And: The AND gate will get optimized out. You cannot use this as a delay, will not work.

Bob

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Thanks for the help Bob!

What other gates can I use? I am simply trying to make a single wire communication line. Instead of separate RX and TX lines. I thought PSoC gates can be used to save some board space instead of using external 74HC126 etc.

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You will need something like a mux to select the signal coming in or going out. Will be difficult to sync the other communication side. There is a one-wire interface, but it is slow and not easy to handle.

I would suggest to let the two-wire UART interface as it is, it will be difficult enough to write a protocol having two devices talk to each other.

What do you need the 74HC126 for? RS232 levels are +-12V and up to 5V can be driven by the PSoC.

Bob

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What other gates can I use? I am simply trying to make a single wire communication line. Instead of separate RX and TX lines. I thought PSoC gates can be used to save some board space instead of using external 74HC126 etc.

Would there be any problem if you use the UART in RS485 mode? Use the transmit direction signal to decouple the internal Tx pin from the external signal (otherwise the two outputs would get shorted). Maybe there's also another solution possible, show your circuit or describe what's acceptable (e.g. a resistor between PSoC Rx and Tx pin to decouple, etc.).

Regards

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odissey1
Level 9
Level 9
First comment on KBA 1000 replies posted 750 replies posted

necdet,

The single-wire UART communication can be accomplished in Master-Slave configuration. Both UARTs are idling in Rx state. To send message the Master switches to Tx mode, sends message and goes into idle Rx state. The slave receives message, goes into Tx mode, responds, and returns back into idle Rx state. Only Master can initiate communication to avoid collision. This way you can communicate PSoC to PSoC only. Each UART should be connected to in-out pin through bufoe, which direction is controlled by ControlReg.

odissey1

UART_1-wire_01.png

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