Multiple channels in RTT

RE: Multiple channels in RTT

Rorisang — Thu, 29 Nov 2018 10:04:11 GMT

Great solution

RE: Multiple channels in RTT

Krzysztof Zaraska — Wed, 20 Dec 2017 14:13:57 GMT

You are right of course! It should be:

 uint8_t data1Buffer[128];
 uint8_t data2Buffer[128];

(post updated).

RE: Multiple channels in RTT

SEGGER - Paul Curtis — Sat, 21 Oct 2017 13:38:22 GMT

Hi,

You use:

uint8_t *data1Buffer[128];
uint8_t *data2Buffer[128];

...and state that this is on the heap. This allocates 128 pointers to uint8_t twice, so 1 KB of memory. You either need a plain pointer (kill the array) and use the equivalent of "malloc" or just remove the * and use a plain array.

Short: this is not a pointer to an array of 128 bytes.

RE: Multiple channels in RTT

koczis — Thu, 12 Oct 2017 18:19:26 GMT

Yes, I call SEGGER_RTT_Init. I do everything exactly as you, except I have 2 additional channels - 3 in all. I wonder whether the buffers shouldn't be placed like they are for channel 0 in "SEGGER_RTT.h":

SEGGER_RTT_PUT_BUFFER_SECTION(SEGGER_RTT_BUFFER_ALIGN(static char _acUpBuffer  [BUFFER_SIZE_UP]));
SEGGER_RTT_PUT_BUFFER_SECTION(SEGGER_RTT_BUFFER_ALIGN(static char _acDownBuffer[BUFFER_SIZE_DOWN]));

RE: Multiple channels in RTT

Krzysztof Zaraska — Thu, 12 Oct 2017 12:42:52 GMT

No, the RTT libs are from clean SDK14. Did you call SEGGER_RTT_Init()?

Here's how I use it now, for reference. (You need to provide _ASSERT macro).

#include <string.h>
#include "SEGGER_RTT.h"
#include "RTT_data.h"
#include "sdk_config.h"

#define RTT_DATA_BUFFER_SIZE 			128					// FIFO size
#define RTT_DATA_CHANNEL 				1					// RTT channel number (RTT Viewer and NRF_LOG use 0)
#define RTT_DATA_USE_BLOCKING_MODE 		1					// Block if not enough space in FIFO
#define RTT_DATA_ASSERT_ON_OVERFLOW 	0					// If RTT_DATA_USE_BLOCKING_MODE is 0, assert if not enough space in the FIFO


uint8_t RTT_buffer[RTT_DATA_BUFFER_SIZE];

bool RTT_initialized = false;

void RTT_data_init(void)
{
#if (RTT_DATA_CHANNEL > SEGGER_RTT_CONFIG_MAX_NUM_UP_BUFFERS-1)
#error "Please increase SEGGER_RTT_CONFIG_MAX_NUM_UP_BUFFERS in sdk_config.h"
#endif

#if NRF_LOG_BACKEND_RTT_ENABLED
	// NRF_LOG will initialize RTT for us
#else
	SEGGER_RTT_Init();
#endif
	
#if RTT_DATA_USE_BLOCKING_MODE
	int mode = SEGGER_RTT_MODE_BLOCK_IF_FIFO_FULL;
#else
	int mode = SEGGER_RTT_MODE_NO_BLOCK_SKIP;
#endif
		
	int ret = SEGGER_RTT_ConfigUpBuffer(RTT_DATA_CHANNEL, "RTT_DATA", RTT_buffer, RTT_DATA_BUFFER_SIZE, mode);
	_ASSERT(ret>=0);
	RTT_initialized = true;
}

void RTT_data_send(uint8_t *data, int size)
{
	_ASSERT(RTT_initialized);
	int ret = SEGGER_RTT_Write(RTT_DATA_CHANNEL, data, size);
#if RTT_DATA_ASSERT_ON_OVERFLOW
	_ASSERT(ret == size);
#endif
}

void RTT_data_send_string(char *string)
{
	_ASSERT(RTT_initialized);
	int ret = SEGGER_RTT_WriteString(RTT_DATA_CHANNEL, string);
#if RTT_DATA_ASSERT_ON_OVERFLOW
	_ASSERT(ret == strlen(string));
#endif
}

RE: Multiple channels in RTT

koczis — Tue, 10 Oct 2017 13:51:44 GMT

Hello,

I did it exactly as you, but I'm having problems with data reception. It appears that I can't use more than one RTT listening application (no matter: Viewer, Client, Logger) to save proper data. When I try, either only one channel is actually receiving anything or data get corrupted. So, I can't seem to achieve what you present on your screenshot. Have you perhaps changed anything else in your RTT lib config?