change rtt settings on target, rtt and systemview not work

[PR2403]

In SEGGER_RTT_Conf.h

// Up-channel 0: RTT
// Up-channel 1: SystemView
//
#ifndef   SEGGER_RTT_MAX_NUM_UP_BUFFERS
  #define SEGGER_RTT_MAX_NUM_UP_BUFFERS             (3)     // Max. number of up-buffers (T->H) available on this target    (Default: 3)
#endif
//
// Most common case:
// Down-channel 0: RTT
// Down-channel 1: SystemView
//
#ifndef   SEGGER_RTT_MAX_NUM_DOWN_BUFFERS
  #define SEGGER_RTT_MAX_NUM_DOWN_BUFFERS           (3)     // Max. number of down-buffers (H->T) available on this target  (Default: 3)
#endif

default is 3, I change it to 2 for less ram useage this cause rtt and systemview not work, no out put, channel reconizating error

9.618 (904) - (II) ---- RTT_CB found at 0x2000ff88
9.620 (  2) - (II)      rtt_check_channel_from_target: 0 20004DD4  1024     0    25
9.622 (  2) - (II)      rtt_check_channel_to_target  : 0 20004C14     8     0     0
9.623 (  1) - (II)      rtt_check_channel_from_target: 1 20004814  1024     0     0
 9.626 (  3) - (II) ---- RTT_CB at 0x2000ff88 seems to be inactive, searching again...
10.228 (602) - (II) searching RTT_CB in 0x20000000..0x2003ffff, prev: 0x00000000
11.132 (904) - (II) ---- RTT_CB found at 0x2000ff88
11.134 (  2) - (II)      rtt_check_channel_from_target: 0 20004DD4  1024     0    30
11.136 (  2) - (II)      rtt_check_channel_to_target  : 0 20004C14     8     0     0
11.137 (  1) - (II)      rtt_check_channel_from_target: 1 20004814  1024     0     0
11.140 (  3) - (II) ---- RTT_CB at 0x2000ff88 seems to be inactive, searching again...
11.742 (602) - (II) searching RTT_CB in 0x20000000..0x2003ffff, prev: 0x00000000

0x20004C14 is channel 1 down buffer address not channel 0

[rgrr]

• how is the probe debug output, if you are using the default settings?
• how much RAM do you save?
• which RTT version are you using?

edited: you do not have to answer this ;-)

[rgrr]

Ok... can confirm that there is something: config in Zephyr

CONFIG_SEGGER_RTT_MAX_NUM_DOWN_BUFFERS=2
CONFIG_SEGGER_RTT_MAX_NUM_UP_BUFFERS=3

is ok, but

CONFIG_SEGGER_RTT_MAX_NUM_DOWN_BUFFERS=2
CONFIG_SEGGER_RTT_MAX_NUM_UP_BUFFERS=2

is not. Output is as follows for NOT OK:

4.421 (  1) - (II) ---- RTT_CB found at 0x20004f10
4.421 (  0) - (II)      rtt_check_channel_from_target: 0 2000808C  8192     0    62
4.422 (  1) - (II)      rtt_check_channel_to_target  : 0 2000A170     8     0     0
4.422 (  0) - (II)      rtt_check_channel_from_target: 1 2000A178 16384     0 16383

and for OK:

4.416 (  0) - (II)      rtt_check_channel_from_target: 0 200080A4  8192     0    62
4.417 (  1) - (II)      rtt_check_channel_to_target  : 0 20008094    16     0     0
4.417 (  0) - (II)      rtt_check_channel_from_target: 1 2000A190 16384     0 16382
4.418 (  1) - (II)      rtt_check_channel_to_target  : 1 2000A188     8     0     0

which means, that the second rtt_check_channel_to_target is not found.

I will look into this.

[rgrr]

There is an obvious bug in rtt_io.c: number of aUp[] is not/wrong taken into account for access to aDown[]. Previous functionality is more or less luck.

[rgrr]

released probe firmware 1.21: https://github.com/rgrr/yapicoprobe/releases/tag/v1.21

Thank you for the bug report & analysis