UART Configuration

[RakeshHegden]

Hi All,

I am Using the NRF52840 DK Device for my application development 

I want 2 UARTS for my application 

I have used the example -  nRF5_SDK_15.3.0_59ac345\examples\peripheral\serial_uartes\pca10056 in this the Pins are configured 8,6,27,26, In my application board i have used pin 19 and 20 for UART0 and 21,22 for UART1.

Unfortunately other than 8,6,27,26,  none of the pins does these UART functions by changing the pin no 

can somebody explain to me how to configure the pin 19 and 20 for UART0 and 21,22 for UART1?

With Regards,

Rakesh 

[haakonsh]

p0.19-22 is already in use by the QSPI peripheral to connect to the external flash on the DK.

See the DK's hardware description: Connector interface for details. 

[RakeshHegden]

So I can't able to use the 19 to 22 pins as UARTE? but the datasheet says  the below 

Figure 100: UARTE configuration The GPIOs used for each UART interface can be chosen from any GPIO on the device and are independently configurable. This enables great flexibility in device pinout and the efficient use of board space and signal routing.

[RakeshHegden]

Thanks for the information 

Understood your point, they are connected to the Flash Memory  

Thanks Again 

[RakeshHegden]

Hi I have disconnected the External flash and updated the code as below 

#define RX_PIN_NUMBER  20//8
#define TX_PIN_NUMBER  19//6

//#define RX_PIN_NUMBER 27//8
//#define TX_PIN_NUMBER 26//6
#define CTS_PIN_NUMBER 7
#define RTS_PIN_NUMBER 5
#define HWFC true

/*
#define BSP_QSPI_SCK_PIN 19
#define BSP_QSPI_CSN_PIN 17
#define BSP_QSPI_IO0_PIN 20
#define BSP_QSPI_IO1_PIN 21
#define BSP_QSPI_IO2_PIN 22
#define BSP_QSPI_IO3_PIN 23
*/

But still, i am unable to see the UARTE communications on PIN 19 and 20m, Do you have any Guss ?

[haakonsh]

I think you're on the right track with regards to your defines. 

Have you scoped the I/O lines with a digital analyzer or are you just trying to read them using a terminal?

We need to verify that the UARTE peripheral is actually configured correctly. To do that we need to know the state of the UART Registers after you've initialized the driver and are ready for a UART transfer. 

Specifically we're interested in registers from SHORTS to CONFIG. 

If the configuration is correct then it might be the flash device loading the I/O lines, I suggest you try cutting SB21 and SB22, see External memory. 

[RakeshHegden]

thanks the SB21 and 22 are the issue sorted the issue 

thanks again