Diff: SWO.cpp

Revision:

0:0fd55660fc26

Child:

1:bae4cff278f6

diff -r 000000000000 -r 0fd55660fc26 SWO.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/SWO.cpp	Fri Mar 28 19:32:13 2014 +0000
@@ -0,0 +1,68 @@
+
+#include "SWO.h"
+
+
+/*********************************************************************
+*
+* Defines for Cortex-M debug unit
+*/
+#define ITM_STIM_U32(n) (*(volatile unsigned int*)(0xE0000000+4*n))  // Stimulus Port n Register word access
+//#define ITM_STIM_U32_0  (*(volatile unsigned int*)0xE0000000)        // Stimulus Port 0 Register word access
+//#define ITM_STIM_U8_0   (*(volatile         char*)0xE0000000)        // Stimulus Port 0 Register byte access
+#define ITM_ENA         (*(volatile unsigned int*)0xE0000E00)        // Trace Enable Ports Register
+#define ITM_TCR         (*(volatile unsigned int*)0xE0000E80)        // Trace control register
+
+
+
+/*********************************************************************
+*
+* SWO_PrintChar()
+*
+* @brief 
+*   Checks if SWO is set up. If it is not, return,
+*    to avoid program hangs if no debugger is connected.
+*   If it is set up, print a character to the ITM_STIM register
+*    in order to provide data for SWO.
+* @param c The Character to be printed.
+* @notes   Additional checks for device specific registers can be added.
+*/
+void SWO_PrintChar(char c) {
+  //
+  // Check if ITM_TCR.ITMENA is set
+  //
+  if ((ITM_TCR & 1) == 0) {
+    return;
+  }
+  //
+  // Check if stimulus port is enabled
+  //
+  if ((ITM_ENA & 1) == 0) {
+    return;
+  }
+  //
+  // Wait until STIMx is ready,
+  // then send data
+  //
+//  while ((ITM_STIM_U8(0) & 1) == 0);
+//  ITM_STIM_U8(0) = c;
+
+  while ((ITM_STIM_U32(0) & 1) == 0);
+  ITM_STIM_U32(0) = c;
+}
+
+/*********************************************************************
+*
+* SWO_PrintString()
+*
+* @brief Print a string via SWO.
+* @param *s The string to be printed.
+*
+*/
+void SWO_PrintString(const char *s) {
+  //
+  // Print out character per character
+  //
+  while (*s) {
+    SWO_PrintChar(*s++);
+  }
+}
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