[rtt] Refactor to use the SEGGER RTT implementation

salkinium · salkinium · commit 0c2a3adbc7f6 · 2025-07-31T12:29:13.000+02:00
diff --git a/examples/blue_pill_f103/rtt/main.cpp b/examples/blue_pill_f103/rtt/main.cpp
@@ -16,8 +16,7 @@
 
 using namespace Board;
 
-Rtt rtt(0);
-modm::IODeviceObjectWrapper< Rtt, modm::IOBuffer::DiscardIfFull > rtt_device(rtt);
+modm::IODeviceWrapper< Rtt<0>, modm::IOBuffer::DiscardIfFull > rtt_device;
 // Set all four logger streams to use RTT
 modm::log::Logger modm::log::debug(rtt_device);
 modm::log::Logger modm::log::info(rtt_device);
diff --git a/examples/blue_pill_f103/rtt/project.xml b/examples/blue_pill_f103/rtt/project.xml
@@ -2,7 +2,7 @@
   <extends>modm:blue-pill-f103</extends>
   <options>
     <option name="modm:build:build.path">../../../build/blue_pill_f103/rtt</option>
-    <option name="modm:platform:rtt:buffer.rx">16</option>
+    <option name="modm:rtt:buffer.rx">16</option>
   </options>
   <modules>
     <module>modm:platform:rtt</module>
diff --git a/examples/blue_pill_f103/servo_pwm/main.cpp b/examples/blue_pill_f103/servo_pwm/main.cpp
@@ -14,8 +14,7 @@
 
 using namespace Board;
 
-Rtt rtt(0);
-modm::IODeviceObjectWrapper< Rtt, modm::IOBuffer::DiscardIfFull > rtt_device(rtt);
+modm::IODeviceWrapper< Rtt<0>, modm::IOBuffer::DiscardIfFull > rtt_device;
 // Set all four logger streams to use RTT
 modm::log::Logger modm::log::debug(rtt_device);
 modm::log::Logger modm::log::info(rtt_device);
diff --git a/examples/blue_pill_f103/servo_pwm/project.xml b/examples/blue_pill_f103/servo_pwm/project.xml
@@ -2,7 +2,7 @@
   <extends>modm:blue-pill-f103</extends>
   <options>
     <option name="modm:build:build.path">../../../build/blue_pill_f103/servo_pwm</option>
-    <option name="modm:platform:rtt:buffer.tx">128</option>
+    <option name="modm:rtt:buffer.tx">128</option>
   </options>
   <modules>
     <module>modm:build:scons</module>
diff --git a/examples/nucleo_f429zi/spi_flash_fatfs/project.xml b/examples/nucleo_f429zi/spi_flash_fatfs/project.xml
@@ -2,7 +2,6 @@
   <extends>modm:nucleo-f429zi</extends>
   <options>
     <option name="modm:build:build.path">../../../build/nucleo_f429zi/spi_flash_fatfs</option>
-    <option name="modm:platform:rtt:buffer.tx">4096</option>
   </options>
   <modules>
     <module>modm:build:scons</module>
diff --git a/examples/nucleo_l476rg/rtt/main.cpp b/examples/nucleo_l476rg/rtt/main.cpp
@@ -15,8 +15,7 @@
 
 using namespace Board;
 
-Rtt rtt(0);
-modm::IODeviceObjectWrapper< Rtt, modm::IOBuffer::DiscardIfFull > rtt_device(rtt);
+modm::IODeviceWrapper< Rtt<0>, modm::IOBuffer::DiscardIfFull > rtt_device;
 modm::IOStream rtt_stream(rtt_device);
 
 #undef MODM_LOG_LEVEL
diff --git a/examples/nucleo_l476rg/rtt/project.xml b/examples/nucleo_l476rg/rtt/project.xml
@@ -2,7 +2,7 @@
   <extends>modm:nucleo-l476rg</extends>
   <options>
     <option name="modm:build:build.path">../../../build/nucleo_l476rg/rtt</option>
-    <option name="modm:platform:rtt:buffer.rx">16</option>
+    <option name="modm:rtt:buffer.rx">16</option>
   </options>
   <modules>
     <module>modm:platform:rtt</module>
diff --git a/examples/stm32f3_discovery/rtt/main.cpp b/examples/stm32f3_discovery/rtt/main.cpp
@@ -15,8 +15,7 @@
 
 using namespace Board;
 
-Rtt rtt(0);
-modm::IODeviceObjectWrapper< Rtt, modm::IOBuffer::DiscardIfFull > rtt_device(rtt);
+modm::IODeviceWrapper< Rtt<0>, modm::IOBuffer::DiscardIfFull > rtt_device;
 // Set all four logger streams to use RTT
 modm::log::Logger modm::log::debug(rtt_device);
 modm::log::Logger modm::log::info(rtt_device);
@@ -85,7 +84,13 @@ main()
 		{
 			LedNorth::toggle();
 
-			MODM_LOG_INFO << "loop: " << counter++ << modm::endl;
+			MODM_LOG_INFO << "loop: " << counter << modm::endl;
+			counter++;
+		}
+		// loopback: read from channel 1, output on channel 2
+		if (uint8_t value; SEGGER_RTT_ReadNoLock(1, &value, 1))
+		{
+			SEGGER_RTT_WriteNoLock(2, &value, 1);
 		}
 	}
 
diff --git a/examples/stm32f3_discovery/rtt/project.xml b/examples/stm32f3_discovery/rtt/project.xml
@@ -2,7 +2,8 @@
   <extends>modm:disco-f303vc</extends>
   <options>
     <option name="modm:build:build.path">../../../build/stm32f3_discovery/rtt</option>
-    <option name="modm:platform:rtt:buffer.rx">16</option>
+    <option name="modm:rtt:buffer.tx">512, 0, 1024</option>
+    <option name="modm:rtt:buffer.rx">16, 32, 0</option>
   </options>
   <modules>
     <module>modm:platform:rtt</module>
diff --git a/src/modm/platform/uart/rtt/module.lb b/src/modm/platform/uart/rtt/module.lb
@@ -1,7 +1,7 @@
 #!/usr/bin/env python3
 # -*- coding: utf-8 -*-
 #
-# Copyright (c) 2021, Niklas Hauser
+# Copyright (c) 2021, 2025, Niklas Hauser
 #
 # This file is part of the modm project.
 #
@@ -14,29 +14,22 @@ def init(module):
     module.name = ":platform:rtt"
     module.description = FileReader("module.md")
 
+
 def prepare(module, options):
     if not options[":target"].has_driver("core:cortex-m*"):
         return False
 
-    module.add_list_option(
-        NumericOption(name="buffer.tx", description="Transmit buffer sizes",
-            minimum=0, maximum="64Ki"), default=512)
-    module.add_list_option(
-        NumericOption(name="buffer.rx", description="Receive buffer sizes",
-            minimum=0, maximum="64Ki"), default=0)
+    module.add_alias(
+        Alias(name="buffer.tx", destination=":rtt:buffer.tx",
+              description="Moved to the `modm:rtt` module"))
+    module.add_alias(
+        Alias(name="buffer.rx", destination=":rtt:buffer.rx",
+              description="Moved to the `modm:rtt` module"))
 
-    module.depends(":architecture:uart")
+    module.depends(":architecture:uart", ":architecture:fiber", ":rtt")
     return True
 
-def validate(env):
-    if len(env["buffer.tx"]) != len(env["buffer.rx"]):
-        raise ValidateException("There must be the same number of TX buffers as RX buffers!")
 
 def build(env):
     env.outbasepath = "modm/src/modm/platform/rtt"
-    env.substitutions = {
-        "buffer_tx": env["buffer.tx"],
-        "buffer_rx": env["buffer.rx"],
-    }
-    env.template("rtt.hpp.in")
-    env.template("rtt.cpp.in")
+    env.copy("rtt.hpp")
diff --git a/src/modm/platform/uart/rtt/module.md b/src/modm/platform/uart/rtt/module.md
@@ -1,116 +1,23 @@
-# Real Time Transfer (RTT)
-
-This module implements the RTT protocol compatible with OpenOCD. RTT works by
-placing multiple ring-buffers in RAM which the debugger read and writes using
-background memory accesses via SWD. It therefore works on any Cortex-M devices
-without extra pins except for the SWDCLK and SWDIO.
-
-See https://www.segger.com/jlink-rtt.html
+# UART over RTT
 
 The RTT channels are exposed as a UART interface which you can use like so:
 
 ```cpp
-modm::platform::Rtt rtt(/* channel= */0);
-// Access data directly via UART interface: eg. loop back
-if (uint8_t data; rtt.read(data)) { rtt.write(data); }
-// Or wrap into an IOStream for printing
-modm::IODeviceObjectWrapper<modm::platform::Rtt,
-                            modm::IOBuffer::DiscardIfFull> rtt_device(rtt);
+// Access data via static methods
+using Rtt = modm::platform::Rtt<0>;
+// Create a software loopback
+if (uint8_t data; Rtt::read(data)) { Rtt::write(data); }
+
+// Wrap into an IOStream
+modm::IODeviceWrapper<Rtt, modm::IOBuffer::DiscardIfFull> rtt_device;
 modm::IOStream stream(rtt_device);
+// Writing data
 stream << "Hello World" << modm::endl;
-// Reading is more annoying
+
+// Reading data from an IOStream
 char data;
 stream.get(data);
 if (data != modm::IOStream::eof) { /* process new data */ }
 ```
 
-You can define the number of channels and their buffer size by setting the
-`buffer.tx` and `buffer.rx` set options. Note that you can define *multiple*
-buffer sizes indexed by channel. Here is an example of three channels:
-
-```xml
-<!-- Channel0: TX only with 256B buffer -->
-<!-- Channel1: RX only with 128B buffer -->
-<!-- Channel2: TX with 512B and RX with 64B buffer -->
-<option name="modm:platform:rtt:buffer.tx">256, 0, 512</option>
-<option name="modm:platform:rtt:buffer.rx">0, 128, 64</option>
-```
-
-You can set the buffer size to `0` if you don't want to use this channel
-direction. This won't allocate a buffer and save a little RAM.
-
-
-## Accessing Data
-
-[OpenOCD has built-in support for RTT][rtt] and modm generates a config that
-opens each RTT channel as a TCP port starting at 9090 (ie. 9090=channel 0,
-9091=channel 1, etc).
-
-```sh
-openocd -f modm/openocd.cfg -c modm_rtt
-```
-
-You can also call this from inside GDB via the `monitor` command:
-
-```
-(gdb) monitor modm_rtt
-rtt: Searching for control block 'SEGGER RTT'
-rtt: Control block found at 0x20001024
-Listening on port 9090 for rtt connections
-(gdb) continue&
-```
-
-You can then use for example `telnet 127.0.0.1 9090` to connect to the stream.
-
-Note that this connection does not halt the target, you should therefore be able
-to use this at any point during program execution.
-
-A simple telnet client is integrated into the build system generator, however,
-it can only connect to one stream at a time (disconnect with Ctrl+D).
-
-```
- $ scons log-rtt
-╭───OpenOCD───> Real Time Transfer
-╰─────RTT────── stm32f103rbt
-Info : rtt: Searching for control block 'SEGGER RTT'
-Info : rtt: Control block found at 0x20000008
-Listening on port 9090 for rtt connections
-loop 51
-loop 52
-loop 53
-^D
-
- $ make log-rtt channel=0
-Info : rtt: Searching for control block 'SEGGER RTT'
-Info : rtt: Control block found at 0x20000008
-Listening on port 9090 for rtt connections
-loop 58
-loop 60
-loop 61
-```
-
-If you want to use this as a proper communication channel with a custom protocol
-you should implement the OpenOCD config yourself (with different ports).
-
-You can also use JLink to access the RTT data, which may be significantly faster
-than OpenOCD if the debug probe has hardware support for the protocol.
-
-```
- $ scons log-rtt-jlink
-╭────JLink────> Real Time Transfer
-╰─────RTT────── stm32l476rgt6
-
-SEGGER J-Link V7.84f - Real time terminal output
-RTT Demo on Nucleo-64
-loop: 0
-loop: 1
-loop: 2
-loop: 3
-loop: 4
-loop: 5
-loop: 6
-loop: 7
-```
-
-
-[rtt]: http://openocd.org/doc/html/General-Commands.html#Real-Time-Transfer-_0028RTT_0029
+To configure the number and size of RTT channels, see the `modm:rtt` module.
diff --git a/src/modm/platform/uart/rtt/rtt.cpp.in b/src/modm/platform/uart/rtt/rtt.cpp.in
diff --git a/src/modm/platform/uart/rtt/rtt.hpp b/src/modm/platform/uart/rtt/rtt.hpp
diff --git a/src/modm/platform/uart/rtt/rtt.hpp.in b/src/modm/platform/uart/rtt/rtt.hpp.in
diff --git a/tools/build_script_generator/module.lb b/tools/build_script_generator/module.lb
