UART Communication between 2 PSoC boards

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BhSr_4843381
Level 3
Level 3
25 sign-ins 10 replies posted 10 questions asked

Hello, 

I am attempting to establish a UART communication between two boards, a PSoC 5LP board and a PSoC 4 (CY042) board. I have tested the UART on both boards by sending and receiving commands on PuTTy, and it works ok. 

I wanted to know whether there needs to be any level shifting module or a pull-down resistor in this interface? If yes, what value?

Also, how do I make this connection? On the PSoC 4, I need to connect the associated pins to the bridge externally. Do I avoid this step and directly connect these pins to the PSoC 5LP? 

 

Thanks for your help. 

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1 Solution
MotooTanaka
Level 9
Level 9
Distributor - Marubun (Japan)
First comment on blog Beta tester First comment on KBA

Hi,

I think that IO voltage of PSoC 5LP is 5V.

We can adjust IO voltage of CY8CKIT-042 using the jumper J9.

So please make sure that both boards are operating in the same IO voltage level.

Then assign UART Pins other then the ones used for KitProg

CY8CKIT-059 (P12[6] UART_RX, P12[7] UART_TX)

CY8CKIT-042 (usually connected via jumper wires)

Then connect

(1) 5LP GND -  042 GND 

(2) 5LP UART_RX - 042 UART_TX

(3) 5LP UART_TX - 042 UART_RX

Hopefully, with these your boards can communicate via UART.

moto

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5 Replies
MotooTanaka
Level 9
Level 9
Distributor - Marubun (Japan)
First comment on blog Beta tester First comment on KBA

Hi,

I think that IO voltage of PSoC 5LP is 5V.

We can adjust IO voltage of CY8CKIT-042 using the jumper J9.

So please make sure that both boards are operating in the same IO voltage level.

Then assign UART Pins other then the ones used for KitProg

CY8CKIT-059 (P12[6] UART_RX, P12[7] UART_TX)

CY8CKIT-042 (usually connected via jumper wires)

Then connect

(1) 5LP GND -  042 GND 

(2) 5LP UART_RX - 042 UART_TX

(3) 5LP UART_TX - 042 UART_RX

Hopefully, with these your boards can communicate via UART.

moto

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Hello, 

I understand how the UART connections are made. Just wanted to know what you mean by "Then assign UART Pins other then the ones used for KitProg"? Do you mean, assign different pins on the PSoC 4 kit? (I plan to use the default RX, TX pins. 

 

 

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MotooTanaka
Level 9
Level 9
Distributor - Marubun (Japan)
First comment on blog Beta tester First comment on KBA

Hi,

On CY8CKIT-042, if you are not connecting the UART pins to the KitProg, then you don't have to change those pins. 

On CY8CKIT-059, P12[6] and P12[7] are connected to the KitProg's UART, so I would recommend you to use anthoer UART with anther set of pins to connect with CY8CKIT-042.

If you are using CY8CKIT-050 and have not connected the UART pins to the on board UART connector, you don't have to change the pins, either.

moto

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Len_CONSULTRON
Level 9
Level 9
Beta tester 500 solutions authored 1000 replies posted

BhSr,

If both boards have VDD = 5V, there's no issue.  No special interface requirements.

Len
"Engineering is an Art. The Art of Compromise."
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Great, thank you!

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