Mercurial > ~darius > hgwebdir.cgi > stm32test
diff libs/STM32F10x_StdPeriph_Lib_V3.5.0/Libraries/CMSIS/CMSIS debug support.htm @ 0:c59513fd84fb
Initial commit of STM32 test code.
| author | Daniel O'Connor <darius@dons.net.au> |
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| date | Mon, 03 Oct 2011 21:19:15 +1030 |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/libs/STM32F10x_StdPeriph_Lib_V3.5.0/Libraries/CMSIS/CMSIS debug support.htm Mon Oct 03 21:19:15 2011 +1030 @@ -0,0 +1,243 @@ +<html> + +<head> +<title>CMSIS Debug Support</title> +<meta http-equiv="Content-Type" content="text/html; charset=windows-1252"> +<meta name="GENERATOR" content="Microsoft FrontPage 6.0"> +<meta name="ProgId" content="FrontPage.Editor.Document"> +<style> +<!-- +/*----------------------------------------------------------- +Keil Software CHM Style Sheet +-----------------------------------------------------------*/ +body { color: #000000; background-color: #FFFFFF; font-size: 75%; font-family: + Verdana, Arial, 'Sans Serif' } +a:link { color: #0000FF; text-decoration: underline } +a:visited { color: #0000FF; text-decoration: underline } +a:active { color: #FF0000; text-decoration: underline } +a:hover { color: #FF0000; text-decoration: underline } +h1 { font-family: Verdana; font-size: 18pt; color: #000080; font-weight: bold; + text-align: Center; margin-right: 3 } +h2 { font-family: Verdana; font-size: 14pt; color: #000080; font-weight: bold; + background-color: #CCCCCC; margin-top: 24; margin-bottom: 3; + padding: 6 } +h3 { font-family: Verdana; font-size: 10pt; font-weight: bold; background-color: + #CCCCCC; margin-top: 24; margin-bottom: 3; padding: 6 } +pre { font-family: Courier New; font-size: 10pt; background-color: #CCFFCC; + margin-left: 24; margin-right: 24 } +ul { list-style-type: square; margin-top: 6pt; margin-bottom: 0 } +ol { margin-top: 6pt; margin-bottom: 0 } +li { clear: both; margin-bottom: 6pt } +table { font-size: 100%; border-width: 0; padding: 0 } +th { color: #FFFFFF; background-color: #000080; text-align: left; vertical-align: + bottom; padding-right: 6pt } +tr { text-align: left; vertical-align: top } +td { text-align: left; vertical-align: top; padding-right: 6pt } +.ToolT { font-size: 8pt; color: #808080 } +.TinyT { font-size: 8pt; text-align: Center } +code { color: #000000; background-color: #E0E0E0; font-family: 'Courier New', Courier; + line-height: 120%; font-style: normal } +/*----------------------------------------------------------- +Notes +-----------------------------------------------------------*/ +p.note { font-weight: bold; clear: both; margin-bottom: 3pt; padding-top: 6pt } +/*----------------------------------------------------------- +Expanding/Contracting Divisions +-----------------------------------------------------------*/ +#expand { text-decoration: none; margin-bottom: 3pt } +img.expand { border-style: none; border-width: medium } +div.expand { display: none; margin-left: 9pt; margin-top: 0 } +/*----------------------------------------------------------- +Where List Tags +-----------------------------------------------------------*/ +p.wh { font-weight: bold; clear: both; margin-top: 6pt; margin-bottom: 3pt } +table.wh { width: 100% } +td.whItem { white-space: nowrap; font-style: italic; padding-right: 6pt; padding-bottom: + 6pt } +td.whDesc { padding-bottom: 6pt } +/*----------------------------------------------------------- +Keil Table Tags +-----------------------------------------------------------*/ +table.kt { border: 1pt solid #000000 } +th.kt { white-space: nowrap; border-bottom: 1pt solid #000000; padding-left: 6pt; + padding-right: 6pt; padding-top: 4pt; padding-bottom: 4pt } +tr.kt { } +td.kt { color: #000000; background-color: #E0E0E0; border-top: 1pt solid #A0A0A0; + padding-left: 6pt; padding-right: 6pt; padding-top: 2pt; + padding-bottom: 2pt } +/*----------------------------------------------------------- +-----------------------------------------------------------*/ +--> + +</style> +</head> + +<body> + +<h1>CMSIS Debug Support</h1> + +<hr> + +<h2>Cortex-M3 ITM Debug Access</h2> +<p> + 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: +</p> +<ul> + <li>ITM Channel 0: used for printf-style output via the debug interface.</li> + <li>ITM Channel 31: is reserved for RTOS kernel awareness debugging.</li> +</ul> + +<h2>Debug IN / OUT functions</h2> +<p>CMSIS provides following debug functions:</p> +<ul> + <li>ITM_SendChar (uses ITM channel 0)</li> + <li>ITM_ReceiveChar (uses global variable)</li> + <li>ITM_CheckChar (uses global variable)</li> +</ul> + +<h3>ITM_SendChar</h3> +<p> + <strong>ITM_SendChar</strong> is used to transmit a character over ITM channel 0 from + the microcontroller system to the debug system. <br> + Only a 8 bit value is transmitted. +</p> +<pre> +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); +}</pre> + +<h3>ITM_ReceiveChar</h3> +<p> + 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. +</p> + +<p> + The globale variable <strong>ITM_RxBuffer</strong> is used to transmit a 8 bit value from debug system + to microcontroller system. <strong>ITM_RxBuffer</strong> is 32 bit wide to enshure a proper handshake. +</p> +<pre> +extern volatile int ITM_RxBuffer; /* variable to receive characters */ +</pre> +<p> + A dedicated bit pattern is used to determin if <strong>ITM_RxBuffer</strong> is empty + or contains a valid value. +</p> +<pre> +#define ITM_RXBUFFER_EMPTY 0x5AA55AA5 /* value identifying ITM_RxBuffer is ready for next character */ +</pre> +<p> + <strong>ITM_ReceiveChar</strong> 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. +</p> +<pre> +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); +} +</pre> + +<h3>ITM_CheckChar</h3> +<p> + <strong>ITM_CheckChar</strong> is used to check if a character is received. +</p> +<pre> +static __INLINE int ITM_CheckChar (void) { + + if (ITM_RxBuffer == ITM_RXBUFFER_EMPTY) { + return (0); /* no character available */ + } else { + return (1); /* character available */ + } +}</pre> + + +<h2>ITM Debug Support in uVision</h2> +<p> + uVision uses in a debug session the <strong>Debug (printf) Viewer</strong> window to + display the debug data. +</p> +<p>Direction microcontroller system -> uVision:</p> +<ul> + <li> + Characters received via ITM communication channel 0 are written in a printf style + to <strong>Debug (printf) Viewer</strong> window. + </li> +</ul> + +<p>Direction uVision -> microcontroller system:</p> +<ul> + <li>Check if <strong>ITM_RxBuffer</strong> variable is available (only performed once).</li> + <li>Read character from <strong>Debug (printf) Viewer</strong> window.</li> + <li>If <strong>ITM_RxBuffer</strong> empty write character to <strong>ITM_RxBuffer</strong>.</li> +</ul> + +<p class="Note">Note</p> +<ul> + <li><p>Current solution does not use a buffer machanism for trasmitting the characters.</p> + </li> +</ul> + +<h2>RTX Kernel awareness in uVision</h2> +<p> + uVision / RTX are using a simple and efficient solution for RTX Kernel awareness. + No format overhead is necessary.<br> + uVsion debugger decodes the RTX events via the 32 / 16 / 8 bit ITM write access + to ITM communication channel 31. +</p> + +<p>Following RTX events are traced:</p> +<ul> + <li>Task Create / Delete event + <ol> + <li>32 bit access. Task start address is transmitted</li> + <li>16 bit access. Task ID and Create/Delete flag are transmitted<br> + High byte holds Create/Delete flag, Low byte holds TASK ID. + </li> + </ol> + </li> + <li>Task switch event + <ol> + <li>8 bit access. Task ID of current task is transmitted</li> + </ol> + </li> +</ul> + +<p class="Note">Note</p> +<ul> + <li><p>Other RTOS information could be retrieved via memory read access in a polling mode manner.</p> + </li> +</ul> + + +<p class="MsoNormal"><span lang="EN-GB"> </span></p> + +<hr> + +<p class="TinyT">Copyright © KEIL - An ARM Company.<br> +All rights reserved.<br> +Visit our web site at <a href="http://www.keil.com">www.keil.com</a>. +</p> + +</body> + +</html> \ No newline at end of file