UART connect external MCU(STM32) transmit and recieved data

[yithwe]

Hi 

    I need to send data from nRF7002 to external CPU(STM32) use UART protocol, for HW nRF7002 P0.20 connect STM32 RX and RF7002 P0.22 connect STM32 TX, I try to use exercise to modify send 8 bytes data and recieved from STM32 8 bytes data, there is no any data recieved data from STM32 and nRF7002, isn't I miss some config for this flow?below is my device three overlay and code, please give suggestion for this, Thanks.

&uart0_default {
	group1 {
		psels = <NRF_PSEL(UART_TX, 0, 20)>, <NRF_PSEL(UART_RTS, 0, 19)>;
	};
};

&uart0_sleep {
	group1 {
		psels = <NRF_PSEL(UART_TX, 0, 20)>,
				<NRF_PSEL(UART_RX, 0, 22)>,
				<NRF_PSEL(UART_RTS, 0, 19)>,
				<NRF_PSEL(UART_CTS, 0, 21)>;
	};
};
&uart0 {
	status = "okay";
	current-speed = <115200>;
	pinctrl-0 = <&uart0_default>;
	pinctrl-1 = <&uart0_sleep>;
	pinctrl-names = "default", "sleep";
};

#define RECEIVE_BUFF_SIZE 8
const struct device *uart= DEVICE_DT_GET(DT_NODELABEL(uart0));
static uint8_t tx_buf[] =   {0x00,0x01,0x02,0x03,0x04,0x05,0x06,0x07};
static uint8_t rx_buf[RECEIVE_BUFF_SIZE] = {0};
int main(void)
{
	int ret;
		if (!device_is_ready(uart)){
		printk("UART device not ready\r\n");
		return 1 ;
	}
	ret = uart_tx(uart, tx_buf, sizeof(tx_buf), SYS_FOREVER_MS);
	if (ret) {
		return 1;
	}
		ret = uart_rx_enable(uart ,rx_buf,sizeof rx_buf,RECEIVE_TIMEOUT);
	if (ret) {
		return 1;
	}
	while (1) {
		k_msleep(SLEEP_TIME_MS);
	}
}

Best Regards

    Tina

          

[Simonr]

Hi

Okay that makes a lot more sense. Looking at your overlay file the following stood out:

&uart0_default {
	group1 {
		psels = <NRF_PSEL(UART_TX, 0, 20)>, <NRF_PSEL(UART_RTS, 0, 19)>;
	};
};

It seems here you're using the TX and RTS pin for UART pins here, which should be TX and RX if I'm not mistaken, try changing the RTS pin to UART_RX, 0, 22 instead, and see if that helps.

Best regards,

Simon

[yithwe]

Hi Simonr

                 I try to modified RTS pin to UART_RX, 0,22 instead, It's doesn't read back any information(below picture), please give any suggestion, Thanks.

another problem is I need to add one more UART for debug log, isn't can activate at the same time?

UART0 is for debuging log (print log for debuging)  

UART1 is for command and small data communicate

I modify for device tree overlay as below, change uart0 and uart1, for code assign uart1 for device.

&i2c0 {	status = "disabled";};
&spi0 {	status = "disabled";};
&spi2 {	status = "disabled";};
&i2c1 {	status = "disabled";};
	

&spi4 {
    compatible = "nordic,nrf-spim";
	status = "okay";
	pinctrl-0 = <&spi4_default>;
	pinctrl-1 = <&spi4_sleep>;
	pinctrl-names = "default", "sleep";
	cs-gpios = <&gpio0 11 (GPIO_ACTIVE_LOW | (1 << 8) | (1 << 9))>;
	stm32f412vgh6: stm32f412vgh6@0 {
		compatible = "st,stm32f412vgh6";
		reg = <0>;
		spi-max-frequency = <DT_FREQ_M(8)>; 
	};


    max-frequency = <DT_FREQ_M(8)>;
};

/* STEP 2.2 - Change the pin configuration */
&pinctrl {
	spi4_default: spi4_default {
		group1 {
				psels = <NRF_PSEL(SPIM_SCK, 0, 8)>,
						<NRF_PSEL(SPIM_MOSI, 0, 9)>,
						<NRF_PSEL(SPIM_MISO, 0, 10)>;
				nordic,drive-mode = <NRF_DRIVE_H0H1>;		
		};
	};

	spi4_sleep: spi4_sleep {
		group1 {
				psels = <NRF_PSEL(SPIM_SCK, 0, 8)>,
						<NRF_PSEL(SPIM_MOSI, 0, 9)>,
						<NRF_PSEL(SPIM_MISO, 0, 10)>;
				low-power-enable;
		};
	};
};

&uart0_default {
	group1 {
		psels = <NRF_PSEL(UART_TX, 1, 1)>, <NRF_PSEL(UART_RTS, 1, 5)>;
	};

    group2 {
        psels = <NRF_PSEL(UART_RX, 1, 0)>, <NRF_PSEL(UART_CTS, 1, 4)>;
    };
};

&uart0_sleep {
	group1 {
		psels = <NRF_PSEL(UART_TX, 1, 1)>,
				<NRF_PSEL(UART_RX, 1, 00)>,
				<NRF_PSEL(UART_RTS, 1, 05)>,
				<NRF_PSEL(UART_CTS, 1, 04)>;
	};
};
&uart0 {
	status = "okay";
	current-speed = <115200>;
	pinctrl-0 = <&uart0_default>;
	pinctrl-1 = <&uart0_sleep>;
	pinctrl-names = "default", "sleep";
};

&uart1_default {
	group1 {
		psels = <NRF_PSEL(UART_TX, 0, 20)>, <NRF_PSEL(UART_RTS, 0, 19)>;
	};
	group2 {
        psels = <NRF_PSEL(UART_RX, 0, 22)>, <NRF_PSEL(UART_CTS, 0, 21)>;
    };
};

&uart1_sleep {
	group1 {
		psels = <NRF_PSEL(UART_TX, 0, 20)>,
				<NRF_PSEL(UART_RX, 0, 22)>,
				<NRF_PSEL(UART_RTS, 0, 19)>,
				<NRF_PSEL(UART_CTS, 0, 21)>;
	};
};
&uart1 {
	status = "okay";
	current-speed = <115200>;
	pinctrl-0 = <&uart1_default>;
	pinctrl-1 = <&uart1_sleep>;
	pinctrl-names = "default", "sleep";
};

#define RECEIVE_BUFF_SIZE 8
const struct device *uart= DEVICE_DT_GET(DT_NODELABEL(uart1));
static uint8_t tx_buf[] =   {0x00,0x01,0x02,0x03,0x04,0x05,0x06,0x07};
static uint8_t rx_buf[RECEIVE_BUFF_SIZE] = {0};
int main(void)
{
	int ret;
		if (!device_is_ready(uart)){
		printk("UART device not ready\r\n");
		return 1 ;
	}
	ret = uart_tx(uart, tx_buf, sizeof(tx_buf), SYS_FOREVER_MS);
	if (ret) {
		return 1;
	}
		ret = uart_rx_enable(uart ,rx_buf,sizeof rx_buf,RECEIVE_TIMEOUT);
	if (ret) {
		return 1;
	}
	while (1) {
		k_msleep(SLEEP_TIME_MS);
	}
}

Best Regards

     Tina

[Naeem Maroof]

Hi Tina,

I am not sure but could the issue be from the other MCU?

[Naeem Maroof]

Also check that the other MCU is also using the same uart configurations.

[yithwe]

Hi Naeem Maroof

                           I am connect stm32 mcu, but I sure the uart configurations are same, we connect the emulator to connect and see the result, nordic 7002-DK tx send message as below and stm32 send back rx message as below.stm32 can't recieved any message and nordic 7002-DK can't read back any message as below picture.

isn't I need to set compatible in overlay for stm32 uart?

tx_buf[] =   {0x00,0x01,0x02,0x03,0x04,0x05,0x06,0x07}

Best Regards

    Tina

[yithwe]

Hi Naeem Maroof

                            It's OK and respone from external MCU, but forexample code tx_buf only can send string?may I try to send hex byte?for this which API can I use?Thanks.

Best Regards

      Tina 

[Naeem Maroof]

so the stum32 is not receiving but 7002dk is sending.

did you check the connections and maybe confirm with the logic analyzer as well?