From b0f0d2e9ca18d8604225bed3c984e4cf1b4c4b3c Mon Sep 17 00:00:00 2001 From: Dimitri Sokolyuk Date: Wed, 10 Feb 2016 20:31:09 +0100 Subject: Initial import --- Libraries/CMSIS/CMSIS debug support.htm | 243 ++++++++++++++++++++++++++++++++ 1 file changed, 243 insertions(+) create mode 100644 Libraries/CMSIS/CMSIS debug support.htm (limited to 'Libraries/CMSIS/CMSIS debug support.htm') diff --git a/Libraries/CMSIS/CMSIS debug support.htm b/Libraries/CMSIS/CMSIS debug support.htm new file mode 100644 index 0000000..efda685 --- /dev/null +++ b/Libraries/CMSIS/CMSIS debug support.htm @@ -0,0 +1,243 @@ + + + +CMSIS Debug Support + + + + + + + + +

CMSIS Debug Support

+ +
+ +

Cortex-M3 ITM Debug Access

+

+ The Cortex-M3 incorporates the Instrumented Trace Macrocell (ITM) that provides together with + the Serial Viewer Output trace capabilities for the microcontroller system. The ITM has + 32 communication channels which are able to transmit 32 / 16 / 8 bit values; two ITM + communication channels are used by CMSIS to output the following information: +

+ + +

Debug IN / OUT functions

+

CMSIS provides following debug functions:

+ + +

ITM_SendChar

+

+ ITM_SendChar is used to transmit a character over ITM channel 0 from + the microcontroller system to the debug system.
+ Only a 8 bit value is transmitted. +

+
+static __INLINE uint32_t ITM_SendChar (uint32_t ch)
+{
+  /* check if debugger connected and ITM channel enabled for tracing */
+  if ((CoreDebug->DEMCR & CoreDebug_DEMCR_TRCENA)  &&
+      (ITM->TCR & ITM_TCR_ITMENA)                  &&
+      (ITM->TER & (1UL << 0))  ) 
+  {
+    while (ITM->PORT[0].u32 == 0);
+    ITM->PORT[0].u8 = (uint8_t)ch;
+  }  
+  return (ch);
+}
+ +

ITM_ReceiveChar

+

+ ITM communication channel is only capable for OUT direction. For IN direction + a globel variable is used. A simple mechansim detects if a character is received. + The project to test need to be build with debug information. +

+ +

+ The globale variable ITM_RxBuffer is used to transmit a 8 bit value from debug system + to microcontroller system. ITM_RxBuffer is 32 bit wide to enshure a proper handshake. +

+
+extern volatile int ITM_RxBuffer;                    /* variable to receive characters                             */
+
+

+ A dedicated bit pattern is used to determin if ITM_RxBuffer is empty + or contains a valid value. +

+
+#define             ITM_RXBUFFER_EMPTY    0x5AA55AA5 /* value identifying ITM_RxBuffer is ready for next character */
+
+

+ ITM_ReceiveChar is used to receive a 8 bit value from the debug system. The function is nonblocking. + It returns the received character or '-1' if no character was available. +

+
+static __INLINE int ITM_ReceiveChar (void) {
+  int ch = -1;                               /* no character available */
+
+  if (ITM_RxBuffer != ITM_RXBUFFER_EMPTY) {
+    ch = ITM_RxBuffer;
+    ITM_RxBuffer = ITM_RXBUFFER_EMPTY;       /* ready for next character */
+  }
+  
+  return (ch); 
+}
+
+ +

ITM_CheckChar

+

+ ITM_CheckChar is used to check if a character is received. +

+
+static __INLINE int ITM_CheckChar (void) {
+
+  if (ITM_RxBuffer == ITM_RXBUFFER_EMPTY) {
+    return (0);                                 /* no character available */
+  } else {
+    return (1);                                 /*    character available */
+  }
+}
+ + +

ITM Debug Support in uVision

+

+ uVision uses in a debug session the Debug (printf) Viewer window to + display the debug data. +

+

Direction microcontroller system -> uVision:

+ + +

Direction uVision -> microcontroller system:

+ + +

Note

+ + +

RTX Kernel awareness in uVision

+

+ uVision / RTX are using a simple and efficient solution for RTX Kernel awareness. + No format overhead is necessary.
+ uVsion debugger decodes the RTX events via the 32 / 16 / 8 bit ITM write access + to ITM communication channel 31. +

+ +

Following RTX events are traced:

+ + +

Note

+ + + +

 

+ +
+ +

Copyright © KEIL - An ARM Company.
+All rights reserved.
+Visit our web site at www.keil.com. +

+ + + + \ No newline at end of file -- cgit v1.2.3