UART connection of nRF 52840-DK and LTC 5800-WHM

[katokatsu6412]

Hello.
I am trying to connect nRF 52840-DK and LTC 5800-WHM with UART.
The communication conditions are as follows.
Baud rate: 115200
Data: 8 bits
Stop bit: 1 bit
Parity: None
Flow control: yes
Signal lines are Tx, Rx, Tx_CTSn, Tx_RTSn.

Tx:P0.06

Rx:P0.08

CTS:P0.07

RTS:P0.05

LTC5800-WHM
www.analog.com/.../5800whmfa.pdf

I am trying to connect in Mode 4 of the UART described in the LTC 5800-WHM data sheet, but a reception interrupt from the LTC 5800-WHM is entered but transmission from the nRF 52840 is not accepted.

Please give me some advice.

nRF 52840-DK
SDK 15.0.0
gcc-arm-none-eabi-7-2018-q2-update-win32

[awneil]

Have you confirmed your basic serial connections & configurations?

1. Can you communicate between just the nRF 52840-DK  and a PC terminal?
2. Can you communicate between just the LTC 5800-WHM   and a PC terminal?

More tips on serial comms debug: https://www.avrfreaks.net/comment/2336161#comment-2336161

and follow the link to https://www.avrfreaks.net/comment/2306116#comment-2306116 

[katokatsu6412]

>> Have you confirmed your basic serial connections & configurations?
>> 1. Can you communicate between just the nRF 52840-DK and a PC terminal?
Yes, communication is done.
I confirmed by UART sample code.

>> 2. Can you communicate between just the LTC 5800-WHM and a PC terminal?
Yes, I can communicate.

[awneil]

katokatsu6412 said:

I confirmed by UART sample code.

and have you confirmed that it's still working with your actual code?

What debugging have you done to see what's going wrong now?

In particular, are you sure that the flow control is working?

[katokatsu6412]

I made a UART connection with the following connection and confirmed the operation.
LTC 5800 - WHM ------------- nRF 52840
   HART_UART_TX ---------- UART_RX (Input)
   HART_UART_RX ---------- UART_TX (Output)
   HART_UART_TX_CTSn --- UART_RTS (Output)
   HART_UART_TX_RTSn --- UART_CTS (Input)

· Although a start notification is being sent from LTC 5800-WHM to nRF 52840, it was confirmed in nRF 52840 that a reception interrupt will not be entered unless transmission processing is performed once.
- A response message was sent to the activation notification from the LTC 5800-WHM, but it was confirmed that the LTC 5800-WHM has not received it.
· We are currently checking where processing stops.