SEGGER_RTT_MODE_BLOCK_IF_FIFO_FULL when no probe

Question

Hello, 
 I use a debugger probe (Segger Jlink) with the sdk_config.h setting SEGGER_RTT_MODE_BLOCK_IF_FIFO_FULL. 
 When my probe is not connected, there my product is blocked => i guess that a probe detection is missing in SEGGER_RTT.c, right ? 
 Where can I fix it please ? 
 
 Thank you

RK · Accepted Answer

well it's not missing, Segger didn't put it in and treats SEGGER_RTT_MODE_BLOCK_IF_FIFO_FULL to mean it'll block if the FIFO is full whether or not you have a probe connected. That' the semantic of that flag. 
 If you don't want that, don't use that flag, or do a probe check yourself when you configure the buffer and choose the flag depending on whether you have a probe.

Gein · Answer

How does one perform a probe check in s/w? 
 Here's a solution... set it to the default non-blocking mode, and only after receiving a keypress decide that there is a connection. I added this API to SEGGER_RTT.c: 
 void SEGGER_RTT_Flags(unsigned up_flags, unsigned down_flags, unsigned *up_flags_old, unsigned *down_flags_old) {
 SEGGER_RTT_CB* p;
 p = &_SEGGER_RTT;

 if (up_flags_old) {
 *up_flags_old = p->aUp[0].Flags;
 }
 if (down_flags_old) {
 *down_flags_old = p->aDown[0].Flags;
 }
 if (up_flags != (unsigned)-1) {
 p->aUp[0].Flags = up_flags;
 }
 if (down_flags != (unsigned)-1) {
 p->aDown[0].Flags = up_flags;
 }
}

SEGGER_RTT_MODE_BLOCK_IF_FIFO_FULL when no probe

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