UARTE0 BAUDRATE setting method

RE: UARTE0 BAUDRATE setting method

Dmitry — Fri, 25 Oct 2019 07:51:23 GMT

Hi,

Values for UART0 and UARTE0 differ by 0,4%. UART allows up to 3% drift, so there's no problem with these settings.

RE: UARTE0 BAUDRATE setting method

yokokawa — Fri, 25 Oct 2019 00:31:19 GMT

This screen is a screen where the UART transmission is executed using Ble_app_uart_c of SDK sample program and the transmission program used is confirmed.
① Function name (nrfx_uarte_tx)
UARTE is used.
(2) UART0 baud rate setting
UART0 baud rate parameter is set
(3) UARTE0 baud rate setting
The parameters are different.
(UART0 baud rate parameter is set.)

I am using UARTE, but the baud rate parameter of UARTE0 is not set correctly.

RE: UARTE0 BAUDRATE setting method

Simonr — Thu, 24 Oct 2019 10:59:45 GMT

Thank you for clarifying, and sorry that I missed that. The reason these baud rates are different is that they are different modules, and require different baud rates to work properly. Anyway, I think you're mistaken with regards to the which modules these examples are using, as they're both using the UART register, which is why it makes sense that they both use the UART baud rate. It is possible to switch and use UARTE instead, but in that case, the code in ble_app_uart switches automatically to the correct baud rate and header files.

Please tell me if anything is unclear, or how you can see that UARTE is the module that is used in the example.

Best regards,

Simon

RE: UARTE0 BAUDRATE setting method

yokokawa — Thu, 24 Oct 2019 02:49:53 GMT

The baud rate value setting differs between UART0 and UARTE0.
(See nrf52_bitfields.h)
UART0 : UART_BAUDRATE_BAUDRATE_Baud115200 = 0x01D7E000
UARTE0: UARTE_BAUDRATE_BAUDRATE_Baud115200 = 0x01D60000

The SDK example programs Ble_app_uart and Ble_app_uart_c use the "UARTE0" function.
But I found "UART0" baud rate value is set. Why? Is this a mistake?
Is it okay to change the baud rate setting of function uart_init() to UARTE0 setting (UARTE_BAUDRATE_BAUDRATE_Baud115200 = 0x01D60000)?

RE: UARTE0 BAUDRATE setting method

Simonr — Wed, 23 Oct 2019 06:47:48 GMT

[quote user="yokokawa"]The values of NRF_UART_BAUDRATE_115200 and NRF_UARTE_BAUDRATE_115200 are different.[/quote]

If you take a look in the nrf_uart.h header file, you can see that if UARTE is defined/present, then NRF_UART_BAUDRATE_115200 = UARTE_BAUDRATE_BAUDRATE_Baud115200. And in nrf_uarte.h you can see that NRF_UARTE_BAUDRATE_115200 = UARTE_BAUDRATE_BAUDRATE_Baud115200. So no, they are not different when using UARTE in your application.

I'm having some trouble understanding what the problem is, to be honest. Could you please try to explain what you're struggling with, as it seems to me that your baud rate is 115200 (which is the correct default baud rate) both for using UART and UARTE.

Best regards,

Simon

RE: UARTE0 BAUDRATE setting method

yokokawa — Tue, 22 Oct 2019 09:51:26 GMT

The BAUDRATE register of UART0 and the BAUDRATE register of UARTE0 exist separately.
The values of NRF_UART_BAUDRATE_115200 and NRF_UARTE_BAUDRATE_115200 are different.
Set NRF_UART_BAUDRATE_115200 in BAUDRATE register of UART0,
Setting NRF_UARTE_BAUDRATE_115200 in the UARTE0 BAUDRATE register changes the contents of the UART0 BAUDRATE register to NRF_UARTE_BAUDRATE_115200.
Is there a way to set them separately?

RE: UARTE0 BAUDRATE setting method

Simonr — Tue, 22 Oct 2019 07:41:00 GMT

If your application is only going to use UARTE, there should not be any problems using just the NRF_UARTE_BAUDRATE_115200 to set the baud rate. Seeing as the two baud rates are the same in the example, it won't matter which of them are set, as the .baud_rate value is the same.

Best regards,

Simon

RE: UARTE0 BAUDRATE setting method

yokokawa — Tue, 22 Oct 2019 03:08:34 GMT

The following program sets "NRF_UART_BAUDRATE_115200" when "UART_PRESENT" is valid, and sets "NRF_UARTE_BAUDRATE_115200" otherwise.
However, if “UART_PRESENT” and “UARTE_PRESENT” are enabled, set “NRF_UART_BAUDRATE_115200”.
For “nRF52832”, “UART_PRESENT” and “UARTE_PRESENT” are valid and “UARTE0” is used, but “NRF_UART_BAUDRATE_115200” is set.
-------------------------------------------------- -------------------------------------------------- -
#if defined (UART_PRESENT)
.baud_rate = NRF_UART_BAUDRATE_115200
#else
.baud_rate = NRF_UARTE_BAUDRATE_115200
#endif
-------------------------------------------------- -------------------------------------------------- -
Is ".baud_rate = NRF_UARTE_BAUDRATE_115200" good without using a judgment statement?
“Ble_app_uart_c” is “.baud_rate = NRF_UART_BAUDRATE_115200” without a judgment sentence. Is it OK to change to “.baud_rate = NRF_UARTE_BAUDRATE_115200”?

RE: UARTE0 BAUDRATE setting method

Simonr — Mon, 21 Oct 2019 12:40:26 GMT

As you can see in the main.c file of the ble_app_uart example, the application checks if you're using UART or UARTE, and sets the baud rate accordingly.

#if defined (UART_PRESENT)
        .baud_rate    = NRF_UART_BAUDRATE_115200
#else
        .baud_rate    = NRF_UARTE_BAUDRATE_115200
#endif

I'm afraid I don't understand what you mean in your last reply, but you can set it by using any of the baud rate values defined in nrf_drv_uart.h and replacing it with the baud rate you want to use in your application.

Best regards,

Simon

RE: UARTE0 BAUDRATE setting method

yokokawa — Mon, 21 Oct 2019 08:17:55 GMT

When used without changing the program, the set value of UART0 is set to UART0 and UARTE0.
Why is the setting value of UART0 set to UART0 and UARTE0 in the program that uses UARTE0?

How can I set the baud rate for both UARTE0 and UART0 correctly?

RE: UARTE0 BAUDRATE setting method

Simonr — Mon, 21 Oct 2019 07:59:56 GMT

The baud rate of both UART and UARTE is configured to 115200 in the uart_init() function, which is the default baud rate in our nRF5 SDK examples. What value do you want to set the baud rate to? You can also check the sdk_config.h file and set the NRFX_UARTE_DEFAULT_CONFIG_BAUDRATE to the default baud rate configuration you like.

Best regards,

Simon