Zephyr modbus rtu server device tree configuration

[avos]

Hi,

I'm trying to use the samples/subsys/modbus/rtu_server/ sample. We use the st3485eb as rs485 driver. The problem is that I don't receive any data.

I'm converting our product from the nordic propritary code to zephyr. The nordic code works perfectly on the setup so it is not a hardware problem. The problem is in the configuration of the uart1 rx and tx lines. The configuration is below. The rx is on gpio0 bit 4 and the tx is on gpio0 bit 5, but it seems that at run time other port or bit values are used. Can you help me with the configuration?

&uart1 {

  status = "okay";

  compatible = "nordic,nrf-uarte";

  pinctrl-0 = <&uart1_default>;

  pinctrl-1 = <&uart1_sleep>;

  pinctrl-names = "default", "sleep";

  current-speed = <9600>;

  /delete-property/ hw-flow-control;

  modbus0 {

    compatible = "zephyr,modbus-serial";

    status = "okay";

        de-gpios = <&gpio0 27 GPIO_ACTIVE_HIGH>;

        re-gpios = <&gpio0 26 GPIO_ACTIVE_HIGH>;

  };

};

&uart1_default {

  group1 {

    psels = <NRF_PSEL(UART_RX, 0, 4)>;

    bias-pull-up;

  };

  group2 {

    psels = <NRF_PSEL(UART_TX, 0, 5)>;

  };

};

&uart1_sleep {

  group1 {

    psels = <NRF_PSEL(UART_RX, 0, 4)>;

    bias-pull-up;

  };

  group2 {

    psels = <NRF_PSEL(UART_TX, 0, 5)>;

  };

};

[Kazi Afroza Sultana]

Hello,

Can you use GPIO pin P1.1 as RX and pin p1.2 as TX in the pincontrol file?

uart1_default: uart1_default {
group1 {
psels = <NRF_PSEL(UART_RX, 1, 1)>;
bias-pull-up;
};
group2 {
psels = <NRF_PSEL(UART_TX, 1, 2)>;
};
};

uart1_sleep: uart1_sleep {
group1 {
psels = <NRF_PSEL(UART_RX, 1, 1)>,
<NRF_PSEL(UART_TX, 1, 2)>;
low-power-enable;
};
};

[avos]

No, the hardware is fixed, I cannot change that. And as I said, with the nordic code (without zephyr) it works this way. Or is there a problem with zephyr and and p0.4 and p0.5 ?

[avos]

I printed out the uart registers directly:

uint32_t *p = (uint32_t *) (0x40028000 + 0x508);
NRF_LOG_INFO("txd: %d\n", *(p + 1));
NRF_LOG_INFO("rxd: %d\n", *(p + 3));

It showed that the rx and tx pins are correct, so this is not the problem. Sorry to bother you, thanks for the help.

[Kazi Afroza Sultana]

Hello,

You have found some solution that is really great.

However, the pins can be set correctly in the register and at the same time still be used by other peripheral and not work.

There is an easy way to read register value like

 NRF_UARTE1->PSEL.TXD and NRF_UARTE1->PSEL.RXD