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

In your original post, you were using the same pins for uart0.

Please make sure that you are using correct pins for uart0 and uar2 (if you are using it) from the compiled DTS.

I have used the PUTTY app for serial terminal.

You can also use the built-in NRF Serial Terminal from the VS Code.

Can you try sending 0x41, 0x42 hex for example to check A and B characters on the console, as the 0x00 and 0x01 are the NULL and SOH characters that would not be displayed.

[yithwe]

Hi Naeem Maroof

                           I try to send 0x41, but it convert to ASCII code, it can't work for our goal, we need to send some hex byte array it's not match in ASCII table, like 0xFE, 0xFD, 0xFC, 0xFB, 0xFA , we need to get this byte and need decide which job need to do, so I need for tx send as real hex byte array.

 For uart0 we use (tx:p1.1, rx:p1.00), uart2 (tx:p0.20,rx:p0.22), overlay as below, for uart2 connect to external MCU(STM32), uart0 is for debug log print.but when I connect external MCU, uart0 print log is not work.what I need to do for two uart work same time?now I'm not change for uart0 baud rate, at the final I need to change the uart0 baud rate as 921600.

I also use SPI for other application, but SPI tx and rx can send hex byte array, it's not change to any type.why uart can't?

&uart0_default {
	group1 {
		psels = <NRF_PSEL(UART_TX, 1, 1)>, <NRF_PSEL(UART_RTS, 1, 5)>;
	};
	group2 {
        psels = <NRF_PSEL(UART_RX, 1, 00)>, <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";
};

&uart2_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)>;
    };
};

&uart2_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)>;
	};
};
&uart2 {
	status = "okay";
	current-speed = <921600>;
	pinctrl-0 = <&uart2_default>;
	pinctrl-1 = <&uart2_sleep>;
	pinctrl-names = "default", "sleep";
};

Best Regards

   Tina 

[Naeem Maroof]

Hi TIna,

yithwe said:

I try to send 0x41, but it convert to ASCII code

The purpose was to test that the uart functionality is working.

Do you confirm that when you send 0x41, you are able to receive the character A?

If that is the case then uart functionality is working, it is only the encoding decoding that shows character for 0x41 but not for 0x01.

For example, you can see below that the number 0x41 can be seen as character A but 0x01 can not be displayed.

[yithwe]

Hi Naeem Maroof

            Do you confirm that when you send 0x41, you are able to receive the character A?

yes, it's work.

it is only the encoding decoding that shows character for 0x41 but not for 0x01.

we need to recieve real 0x41, not for character, do you have any suggestion for this issue or any API we can use?Thanks.

Best Regards

     Tina

[Naeem Maroof]

It is the terminal that is displaying it like this.

Can you change setting to receive HEX:

(As in the lower right corner)

[yithwe]

Hi Naeem Maroof

                            it's work on  this terminal as I want to transmit, Thanks.

Best Regards

      Tina