CC2540 UART Rx Problem

Hello SATTAR MALOKANI,
ISR-based serial communication is not recommended, because of the radio-interrupts that can both preempt and block your UART Isrs. I recommend that you use DMA. Look at the drivers that comes with the BLE stack install:

ti.com/ble-stack (Look for hal_uart.c or open a project that use this driver)

If you only need one channel you can use DMA channel 3&4:
e2e.ti.com/.../1106877

Hi Sattar Malokani,

I have exactly the same problem but using UART1 on P1 alt 1. Did you find already any solution on your problem? Exactly as yours UART0 works OK.

Thank you in advance!
BR
Refik

Hi Rafik Halilo,

yes I found solution for that one TI employee clear my confusion.

By default USART0 is available on port P0, and default mode is SPI. and you can see that in datasheet I/O GPIO table SPI clock bit is conflicting with RX pin of USART1.

So there exits two solutions.

1. Give higher priority to USART1 over USART0.

2. Shift USART0 to alternate location 2, when you shift then USART0 is available on P1. so P0 is now free to be used.

I tried both methods and they working fine.

I hope this will work with you.

regards,

Sattar Malokani

Hi Refiq,

first make sure that your both configurations are correct, and you can view register inside IAR EW debugger,

and configuration should be like that.

// if USART port Alternative 1 is required and

//USART0 is required on P0

#define P2DIR_PRIP0_USART0 (0x00 << 6) // USART 0 has priority, then USART 1, then Timer 1
#define P2DIR_PRIP0_USART1 (0x01 << 6) // USART 1 has priority, then USART 0, then Timer 1

PERCFG &= ~0x01; /* Configure USART0 for Alternative 1 */ 

P0SEL |= 0x0C; /* Configure Port P0 pins for UART Peripheral function */

//USART1 is required on P0

PERCFG &= ~0x02; /* Configure USART1 for alternative 1 */
P2DIR = P2DIR_PRIP0_USART1; /* Give USART1 priority on P0*/
P0SEL |= 0x30; /* Configure Port P0 pins for UART Peripheral function */

* Else USART port Alternative 2 is required */

// USART0 is required on P1

PERCFG |= 0x01; /* Configure USART0 for Alternative 2 */
P1SEL |= 0x30; /* Configure Port P1 pins for UART Peripheral function */

/* USART1 is Desired  on P1*/

PERCFG |= 0x02; /* Configure USART1 for alternative 1 */
P1SEL |= 0xC0; /* Configure Port P1 pins for UART Peripheral function */

Above code is only to select USART either on P0 or P1. once you configures this, then you have to select what you want on USART, You want UART Mode or SPI Mode,

In your case you want UART mode so configuration should be like this:

// USART1 baud rate 115200

U1BAUD = 0xD8;

U1UCR = 0x02;

U1GCR = 0x0B;

U1CSR = 0xC0;

//USART0 baud rate 115200

U0BAUD = 0xD8;

U0UCR = 0x02;

U0GCR = 0x0B;

U0CSR = 0xC0;

then next thing is interrupt configuration and should be like this, 

 /* USART0 is desired */

URX0IF = 0;
U0CSR |= 0x40; /* UART Receiver enable (this is already configured above but for make RE is enable so configure again)*/
IEN0 |= 0x04;

/* USART1 is desired */

URX1IF = 0;
U1CSR |= 0x40; /* UART Receiver enable */
IEN0 |= 0x08;

Now you have succesully configured UART on both ports, last touch is to enable global interrupt. 

In IAR EW put this intrinsic function __enable_interrupt(); just before while(1);

or you can do by this 

IEN0 |= 0x80;

I hope this will work. 

regards, 

Sattar Malokani

Hi Sattar,

Thank you very much for your detailed explanation! I've spent whole day today checking different configurations, but without any result. Finally I've decided to blame the HW and it worked !!! :)
First I was working with one very old TI USB dongle. Now I've tried with my own board and it worked. I don't know why the dongle is not working but I will investigate this later.
Thank you again for all of your help!
BR
Refik