UART usage - I cannot see the light in the SDK

[Thomas]

In advance I would like to say I’m sorry for the frustration that this message reflects…Event though I have been using the UART for some time, adding more functionality makes me search documentation for a UART description, and this makes me really frustrated.

I have what I think is a relatively simple need, I want to use UART0 and UART1 on a nRF32840 (both for some RS485 communication).

 

I do not care if it is NRF_DRV, NRFX or APP layer, anything that can be made to work will do!

 

Originally, I thought that selecting between NRF or NRFX was simple; documents suggest that NRF is legacy and I should use the "new" NRFX layer.

So selecting NRFX_UART_ENABLE would be logical and then including nrfx_uart.c driver file.....

But nothing is that simple with this SDK.... there always seems to be a mess of dependencies between configuration macros and files you need to include. and absolutely nothing that documents it (except heavy reading of header files of course ;-). I would love to see. “If you want this layer, tick this in SDK config and include ….”)

Well initial suggestion as above for NRFX just creates a bunch of errors…. so what is the combination needed...

It seems I can choose between using:

1 nrf_drv_uart

2 nrfx_uart

3 nrfx_uarte

4 app_uart

Can anyone suggest settings that will make just one of these options work, it would be highly appreciated and hopefully spare me a lot of testing and experimentation.

What I’m looking for what is a combination of what should be in SDK Config for

NRFX_UARTE section

NRFX_UART section

NRF_DRV (UART_ENABLED) section

APP_UART_ENABLED (+APP_FIFO_ENABLED) section

And any other sections that have dependencies!

I want to be able to call ???_init, send one or more bytes and receive bytes one by one

[Edvin]

Hello,

I understand your frustratsion, as this seems to be quite confusing for a lot of users since we introduced the nrfx drivers. 

First, let me say that there is no choice between legacy and nrfx drivers in the examples in the SDK. I believe some of the old drivers are still present, but you will see that all the examples use the nrfx drivers. Now, the confusing part is that the sdk_config.h file includes both the NRFX and the legacy defines. The reason for this was to make the examples easier to port (backward compatibility), but it has caused a lot of confusion.

You are probably not aware of the file apply_old_config.h, but if you open it, you will see how the different defines are being set. Basically, if the legacy defines are defined, they will overwrite the NRFX_... defines from sdk_config.h. You will however see if you follow the definitions for the driver functions that there is a port layer between the legacy names and the nrfx drivers.

E.g. nrf_drv_uart_init() calls nrfx_uart_init() or nrfx_uarte_init() depending on the NRF_DRV_UART_WITH_UARTE and NRF_DRV_UART_WITH_UART define.

My recommendation is that you set all the NRF_UART defines and the NRFX_UART defines in sdk_config.h equal to each other, and take a look in apply_old_config.h.

There is also an example in the SDK15.3.0\examples\peripheral\serial_uartes that uses both UARTs. You can read about it's description here.

It should also be possible to use the app_uart library, that is used in e.g. the ble_app_uart example, and add another uart. Just set both the legacy and nrfx defines to be the same. If you do this, which I believe that you have tried, what sort of errors do you encounter?

Best regards,

Edvin

[Thomas]

Tried out nrf_serial library. But unfortunately again stuck.

<error> app: ERROR 8 [NRF_ERROR_INVALID_STATE] at ..\..\..\..\..\..\components\libraries\log\src\nrf_log_backend_uart.c:67
PC at: 0x00030559

Cant really figure out why.

In main I only initialize log and timers and then I try to initialize serial library.

It fails inside nrf_serial_init() in the function nrf_drf_uart_init() when forwarding the call to nrfx_uart_init(). This function seems to get something wrong. Really difficult to see what.

I have taken all configuration from the example only changed a little:

NRF_SERIAL_DRV_UART_CONFIG_DEF(m_uart_drv_config,
RX1_PIN_NUMBER, TX1_PIN_NUMBER,
0, 0,
NRF_UART_HWFC_DISABLED, NRF_UART_PARITY_EXCLUDED,
NRF_UART_BAUDRATE_9600,
UART_DEFAULT_CONFIG_IRQ_PRIORITY);

#define SERIAL_FIFO_TX_SIZE 32
#define SERIAL_FIFO_RX_SIZE 32

NRF_SERIAL_QUEUES_DEF(serial_queues, SERIAL_FIFO_TX_SIZE, SERIAL_FIFO_RX_SIZE);

#define SERIAL_BUFF_TX_SIZE 1
#define SERIAL_BUFF_RX_SIZE 1

NRF_SERIAL_BUFFERS_DEF(serial_buffs, SERIAL_BUFF_TX_SIZE, SERIAL_BUFF_RX_SIZE);
NRF_SERIAL_CONFIG_DEF(serial_config, NRF_SERIAL_MODE_IRQ, &serial_queues, &serial_buffs, SerialEventHandler, SerialSleepHandler);
NRF_SERIAL_UART_DEF(serial_uart, 0);

And the just calling:

ret = nrf_serial_init(&serial_uart, &m_uart_drv_config, &serial_config);
APP_ERROR_CHECK(ret);

As good as I could, I also copied the sdk_config parameters so all drivers are enabled no instances checked (as in the example).

Anyone got a clue what I'm missing?

[Edvin]

Thomas said:

<error> app: ERROR 8 [NRF_ERROR_INVALID_STATE] at ..\..\..\..\..\..\components\libraries\log\src\nrf_log_backend_uart.c:67

 It looks like you are trying to use UART as logging backend as well as in your application. Is that correct? Go to sdk_config.h and try to set:

#define NRF_LOG_BACKEND_UART_ENABLED 0

and

#define NRF_LOG_BACKEND_RTT_ENABLED 1

To use the RTT backend  for the log instead of the UART backend.

[Thomas]

Right got that - so I now have it running for a bit until asserts and nothing on the port.... but still fighting ;-)

[Edvin]

Try to define debug in your preprocessor defines (please let me know what IDE you use if you don't know how to do this), and monitor your RTT log. It may not be related to UART at all.

BR,

Edvin

[Thomas]

I have defined debug, but i removed log as I now decided to move to my real target and give it a test. 

I am using Keil and a PCA10056 board for testing my real target is using ULINK2 and no available serial ports as both are RS485.

[Thomas]

Hmmm - tried to copy configuration into my main project.

Added serial to the sdk_config and included nrfx_uarte and also the queue library module that I as not previously using.

Linker error:

Symbol UARTE0_UART0_IRQHandler multiply defined (by nrfx_uarte.o and nrfx_uart.o).

Not really understand as I was thinking I had same configuration as in test, but of course with all the macroes it is difficult to verify. 

In the test project both modules are linked without causing this problem, so it must be #define macros causing this.

[Thomas]

Still havent figured out how to select if nrf_serial is using uart or uarte.... (actually how to control if nrf_drv_uart is using uart or uarte).

[Thomas]

Trying to remove nrtx_uart.c or nrfx_uarte.c from the build will just give a number of unresolved refs. for the rx, tx etc. functions (referred from nrf_serial).

How do I prevent one of the modules from creating interrupt handler...