1 /*********************************************************************
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2 * SEGGER MICROCONTROLLER GmbH & Co. KG *
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3 * Solutions for real time microcontroller applications *
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4 **********************************************************************
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6 * (c) 2014-2014 SEGGER Microcontroller GmbH & Co. KG *
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8 * Internet: www.segger.com Support: support@segger.com *
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10 **********************************************************************
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11 ----------------------------------------------------------------------
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14 Purpose : Implementation of SEGGER real-time terminal (RTT) which allows
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15 real-time terminal communication on targets which support
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16 debugger memory accesses while the CPU is running.
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18 Type "int" is assumed to be 32-bits in size
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19 H->T Host to target communication
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20 T->H Target to host communication
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22 RTT channel 0 is always present and reserved for Terminal usage.
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23 Name is fixed to "Terminal"
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25 ---------------------------END-OF-HEADER------------------------------
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28 #include "SEGGER_RTT_Conf.h"
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29 #include "SEGGER_RTT.h"
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31 #include <string.h> // for memcpy
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33 /*********************************************************************
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35 * Defines, configurable
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37 **********************************************************************
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40 #ifndef BUFFER_SIZE_UP
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41 #define BUFFER_SIZE_UP (1024) // Size of the buffer for terminal output of target, up to host
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44 #ifndef BUFFER_SIZE_DOWN
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45 #define BUFFER_SIZE_DOWN (16) // Size of the buffer for terminal input to target from host (Usually keyboard input)
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48 #ifndef SEGGER_RTT_MAX_NUM_UP_BUFFERS
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49 #define SEGGER_RTT_MAX_NUM_UP_BUFFERS (1) // Number of up-buffers (T->H) available on this target
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52 #ifndef SEGGER_RTT_MAX_NUM_DOWN_BUFFERS
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53 #define SEGGER_RTT_MAX_NUM_DOWN_BUFFERS (1) // Number of down-buffers (H->T) available on this target
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56 #ifndef SEGGER_RTT_LOCK
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57 #define SEGGER_RTT_LOCK()
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60 #ifndef SEGGER_RTT_UNLOCK
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61 #define SEGGER_RTT_UNLOCK()
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64 #ifndef SEGGER_RTT_IN_RAM
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65 #define SEGGER_RTT_IN_RAM (0)
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68 /*********************************************************************
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72 **********************************************************************
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75 #define MIN(a, b) (((a) < (b)) ? (a) : (b))
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76 #define MAX(a, b) (((a) > (b)) ? (a) : (b))
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78 #define MEMCPY(a, b, c) memcpy((a),(b),(c))
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81 // For some environments, NULL may not be defined until certain headers are included
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87 /*********************************************************************
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91 **********************************************************************
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95 // Description for a circular buffer (also called "ring buffer")
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96 // which is used as up- (T->H) or down-buffer (H->T)
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99 const char* sName; // Optional name. Standard names so far are: "Terminal", "VCom"
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100 char* pBuffer; // Pointer to start of buffer
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101 int SizeOfBuffer; // Buffer size in bytes. Note that one byte is lost, as this implementation does not fill up the buffer in order to avoid the problem of being unable to distinguish between full and empty.
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102 volatile int WrOff; // Position of next item to be written by either host (down-buffer) or target (up-buffer). Must be volatile since it may be modified by host (down-buffer)
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103 volatile int RdOff; // Position of next item to be read by target (down-buffer) or host (up-buffer). Must be volatile since it may be modified by host (up-buffer)
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104 int Flags; // Contains configuration flags
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108 // RTT control block which describes the number of buffers available
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109 // as well as the configuration for each buffer
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113 char acID[16]; // Initialized to "SEGGER RTT"
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114 int MaxNumUpBuffers; // Initialized to SEGGER_RTT_MAX_NUM_UP_BUFFERS (type. 2)
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115 int MaxNumDownBuffers; // Initialized to SEGGER_RTT_MAX_NUM_DOWN_BUFFERS (type. 2)
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116 RING_BUFFER aUp[SEGGER_RTT_MAX_NUM_UP_BUFFERS]; // Up buffers, transferring information up from target via debug probe to host
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117 RING_BUFFER aDown[SEGGER_RTT_MAX_NUM_DOWN_BUFFERS]; // Down buffers, transferring information down from host via debug probe to target
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120 /*********************************************************************
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124 **********************************************************************
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127 // Allocate buffers for channel 0
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129 static char _acUpBuffer [BUFFER_SIZE_UP];
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130 static char _acDownBuffer[BUFFER_SIZE_DOWN];
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132 // Initialize SEGGER Real-time-Terminal control block (CB)
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134 static SEGGER_RTT_CB _SEGGER_RTT = {
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135 #if SEGGER_RTT_IN_RAM
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140 SEGGER_RTT_MAX_NUM_UP_BUFFERS,
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141 SEGGER_RTT_MAX_NUM_DOWN_BUFFERS,
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142 {{ "Terminal", &_acUpBuffer[0], sizeof(_acUpBuffer), 0, 0, SEGGER_RTT_MODE_NO_BLOCK_SKIP }},
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143 {{ "Terminal", &_acDownBuffer[0], sizeof(_acDownBuffer), 0, 0, SEGGER_RTT_MODE_NO_BLOCK_SKIP }},
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146 static char _ActiveTerminal;
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148 /*********************************************************************
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152 **********************************************************************
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155 /*********************************************************************
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159 * Function description
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160 * ANSI compatible function to determine the length of a string
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163 * Length of string in bytes.
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166 * s Pointer to \0 terminated string.
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169 * (1) s needs to point to an \0 terminated string. Otherwise proper functionality of this function is not guaranteed.
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171 static int _strlen(const char* s) {
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188 /*********************************************************************
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192 * Function description
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193 * In case SEGGER_RTT_IN_RAM is defined,
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194 * _Init() modifies the ID of the RTT CB to allow identifying the
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195 * RTT Control Block Structure in the data segment.
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197 static void _Init(void) {
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198 #if SEGGER_RTT_IN_RAM
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199 if (_SEGGER_RTT.acID[10] == 'I') {
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200 _SEGGER_RTT.acID[10] = '\0';
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205 /*********************************************************************
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209 **********************************************************************
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211 /*********************************************************************
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215 * Function description
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216 * Reads characters from SEGGER real-time-terminal control block
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217 * which have been previously stored by the host.
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220 * BufferIndex Index of Down-buffer to be used. (e.g. 0 for "Terminal")
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221 * pBuffer Pointer to buffer provided by target application, to copy characters from RTT-down-buffer to.
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222 * BufferSize Size of the target application buffer
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225 * Number of bytes that have been read
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227 int SEGGER_RTT_Read(unsigned BufferIndex, char* pBuffer, unsigned BufferSize) {
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229 unsigned NumBytesRead;
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235 RdOff = _SEGGER_RTT.aDown[BufferIndex].RdOff;
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236 WrOff = _SEGGER_RTT.aDown[BufferIndex].WrOff;
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239 // Read from current read position to wrap-around of buffer, first
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241 if (RdOff > WrOff) {
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242 NumBytesRem = _SEGGER_RTT.aDown[BufferIndex].SizeOfBuffer - RdOff;
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243 NumBytesRem = MIN(NumBytesRem, (int)BufferSize);
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244 MEMCPY(pBuffer, _SEGGER_RTT.aDown[BufferIndex].pBuffer + RdOff, NumBytesRem);
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245 NumBytesRead += NumBytesRem;
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246 pBuffer += NumBytesRem;
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247 BufferSize -= NumBytesRem;
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248 RdOff += NumBytesRem;
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250 // Handle wrap-around of buffer
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252 if (RdOff == _SEGGER_RTT.aDown[BufferIndex].SizeOfBuffer) {
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257 // Read remaining items of buffer
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259 NumBytesRem = WrOff - RdOff;
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260 NumBytesRem = MIN(NumBytesRem, (int)BufferSize);
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261 if (NumBytesRem > 0) {
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262 MEMCPY(pBuffer, _SEGGER_RTT.aDown[BufferIndex].pBuffer + RdOff, NumBytesRem);
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263 NumBytesRead += NumBytesRem;
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264 pBuffer += NumBytesRem;
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265 BufferSize -= NumBytesRem;
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266 RdOff += NumBytesRem;
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268 if (NumBytesRead) {
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269 _SEGGER_RTT.aDown[BufferIndex].RdOff = RdOff;
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271 SEGGER_RTT_UNLOCK();
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272 return NumBytesRead;
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275 /*********************************************************************
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279 * Function description
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280 * Stores a specified number of characters in SEGGER RTT
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281 * control block which is then read by the host.
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284 * BufferIndex Index of "Up"-buffer to be used. (e.g. 0 for "Terminal")
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285 * pBuffer Pointer to character array. Does not need to point to a \0 terminated string.
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286 * NumBytes Number of bytes to be stored in the SEGGER RTT control block.
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289 * Number of bytes which have been stored in the "Up"-buffer.
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292 * (1) If there is not enough space in the "Up"-buffer, remaining characters of pBuffer are dropped.
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294 int SEGGER_RTT_Write(unsigned BufferIndex, const char* pBuffer, unsigned NumBytes) {
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295 int NumBytesToWrite;
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296 unsigned NumBytesWritten;
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299 // Target is not allowed to perform other RTT operations while string still has not been stored completely.
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300 // Otherwise we would probably end up with a mixed string in the buffer.
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305 // In case we are not in blocking mode,
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306 // we need to calculate, how many bytes we can put into the buffer at all.
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308 if ((_SEGGER_RTT.aUp[BufferIndex].Flags & SEGGER_RTT_MODE_MASK) != SEGGER_RTT_MODE_BLOCK_IF_FIFO_FULL) {
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309 RdOff = _SEGGER_RTT.aUp[BufferIndex].RdOff;
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310 NumBytesToWrite = RdOff - _SEGGER_RTT.aUp[BufferIndex].WrOff - 1;
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311 if (NumBytesToWrite < 0) {
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312 NumBytesToWrite += _SEGGER_RTT.aUp[BufferIndex].SizeOfBuffer;
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315 // If the complete data does not fit in the buffer, check if we have to skip it completely or trim the data
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317 if ((int)NumBytes > NumBytesToWrite) {
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318 if ((_SEGGER_RTT.aUp[BufferIndex].Flags & SEGGER_RTT_MODE_MASK) == SEGGER_RTT_MODE_NO_BLOCK_SKIP) {
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319 SEGGER_RTT_UNLOCK();
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322 NumBytes = NumBytesToWrite;
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327 // Early out if nothing is to do
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329 if (NumBytes == 0) {
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330 SEGGER_RTT_UNLOCK();
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334 // Write data to buffer and handle wrap-around if necessary
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336 NumBytesWritten = 0;
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338 RdOff = _SEGGER_RTT.aUp[BufferIndex].RdOff; // May be changed by host (debug probe) in the meantime
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339 NumBytesToWrite = RdOff - _SEGGER_RTT.aUp[BufferIndex].WrOff - 1;
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340 if (NumBytesToWrite < 0) {
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341 NumBytesToWrite += _SEGGER_RTT.aUp[BufferIndex].SizeOfBuffer;
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343 NumBytesToWrite = MIN(NumBytesToWrite, (_SEGGER_RTT.aUp[BufferIndex].SizeOfBuffer - _SEGGER_RTT.aUp[BufferIndex].WrOff)); // Number of bytes that can be written until buffer wrap-around
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344 NumBytesToWrite = MIN(NumBytesToWrite, (int)NumBytes);
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345 MEMCPY(_SEGGER_RTT.aUp[BufferIndex].pBuffer + _SEGGER_RTT.aUp[BufferIndex].WrOff, pBuffer, NumBytesToWrite);
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346 NumBytesWritten += NumBytesToWrite;
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347 pBuffer += NumBytesToWrite;
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348 NumBytes -= NumBytesToWrite;
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349 _SEGGER_RTT.aUp[BufferIndex].WrOff += NumBytesToWrite;
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350 if (_SEGGER_RTT.aUp[BufferIndex].WrOff == _SEGGER_RTT.aUp[BufferIndex].SizeOfBuffer) {
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351 _SEGGER_RTT.aUp[BufferIndex].WrOff = 0;
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353 } while (NumBytes);
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354 SEGGER_RTT_UNLOCK();
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355 return NumBytesWritten;
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358 /*********************************************************************
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360 * SEGGER_RTT_WriteString
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362 * Function description
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363 * Stores string in SEGGER RTT control block.
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364 * This data is read by the host.
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367 * BufferIndex Index of "Up"-buffer to be used. (e.g. 0 for "Terminal")
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368 * s Pointer to string.
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371 * Number of bytes which have been stored in the "Up"-buffer.
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374 * (1) If there is not enough space in the "Up"-buffer, depending on configuration,
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375 * remaining characters may be dropped or RTT module waits until there is more space in the buffer.
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376 * (2) String passed to this function has to be \0 terminated
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377 * (3) \0 termination character is *not* stored in RTT buffer
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379 int SEGGER_RTT_WriteString(unsigned BufferIndex, const char* s) {
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383 return SEGGER_RTT_Write(BufferIndex, s, Len);
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386 /*********************************************************************
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388 * SEGGER_RTT_GetKey
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390 * Function description
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391 * Reads one character from the SEGGER RTT buffer.
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392 * Host has previously stored data there.
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395 * < 0 No character available (buffer empty).
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396 * >= 0 Character which has been read. (Possible values: 0 - 255)
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399 * (1) This function is only specified for accesses to RTT buffer 0.
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401 int SEGGER_RTT_GetKey(void) {
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405 r = SEGGER_RTT_Read(0, &c, 1);
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407 return (int)(unsigned char)c;
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412 /*********************************************************************
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414 * SEGGER_RTT_WaitKey
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416 * Function description
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417 * Waits until at least one character is avaible in the SEGGER RTT buffer.
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418 * Once a character is available, it is read and this function returns.
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421 * >=0 Character which has been read.
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424 * (1) This function is only specified for accesses to RTT buffer 0
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425 * (2) This function is blocking if no character is present in RTT buffer
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427 int SEGGER_RTT_WaitKey(void) {
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431 r = SEGGER_RTT_GetKey();
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436 /*********************************************************************
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438 * SEGGER_RTT_HasKey
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440 * Function description
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441 * Checks if at least one character for reading is available in the SEGGER RTT buffer.
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444 * 0 No characters are available to read.
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445 * 1 At least one character is available.
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448 * (1) This function is only specified for accesses to RTT buffer 0
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450 int SEGGER_RTT_HasKey(void) {
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454 RdOff = _SEGGER_RTT.aDown[0].RdOff;
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455 if (RdOff != _SEGGER_RTT.aDown[0].WrOff) {
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461 /*********************************************************************
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463 * SEGGER_RTT_ConfigUpBuffer
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465 * Function description
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466 * Run-time configuration of a specific up-buffer (T->H).
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467 * Buffer to be configured is specified by index.
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468 * This includes: Buffer address, size, name, flags, ...
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474 int SEGGER_RTT_ConfigUpBuffer(unsigned BufferIndex, const char* sName, char* pBuffer, int BufferSize, int Flags) {
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476 if (BufferIndex < (unsigned)_SEGGER_RTT.MaxNumUpBuffers) {
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478 if (BufferIndex > 0) {
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479 _SEGGER_RTT.aUp[BufferIndex].sName = sName;
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480 _SEGGER_RTT.aUp[BufferIndex].pBuffer = pBuffer;
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481 _SEGGER_RTT.aUp[BufferIndex].SizeOfBuffer = BufferSize;
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482 _SEGGER_RTT.aUp[BufferIndex].RdOff = 0;
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483 _SEGGER_RTT.aUp[BufferIndex].WrOff = 0;
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485 _SEGGER_RTT.aUp[BufferIndex].Flags = Flags;
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486 SEGGER_RTT_UNLOCK();
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492 /*********************************************************************
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494 * SEGGER_RTT_ConfigDownBuffer
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496 * Function description
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497 * Run-time configuration of a specific down-buffer (H->T).
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498 * Buffer to be configured is specified by index.
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499 * This includes: Buffer address, size, name, flags, ...
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505 int SEGGER_RTT_ConfigDownBuffer(unsigned BufferIndex, const char* sName, char* pBuffer, int BufferSize, int Flags) {
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507 if (BufferIndex < (unsigned)_SEGGER_RTT.MaxNumDownBuffers) {
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509 if (BufferIndex > 0) {
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510 _SEGGER_RTT.aDown[BufferIndex].sName = sName;
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511 _SEGGER_RTT.aDown[BufferIndex].pBuffer = pBuffer;
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512 _SEGGER_RTT.aDown[BufferIndex].SizeOfBuffer = BufferSize;
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513 _SEGGER_RTT.aDown[BufferIndex].RdOff = 0;
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514 _SEGGER_RTT.aDown[BufferIndex].WrOff = 0;
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516 _SEGGER_RTT.aDown[BufferIndex].Flags = Flags;
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517 SEGGER_RTT_UNLOCK();
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523 /*********************************************************************
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527 * Function description
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528 * Initializes the RTT Control Block.
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529 * Should be used in RAM targets, at start of the application.
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532 void SEGGER_RTT_Init (void) {
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536 /*********************************************************************
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538 * SEGGER_RTT_SetTerminal
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540 * Function description
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541 * Sets the terminal to be used for output on channel 0.
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544 void SEGGER_RTT_SetTerminal (char TerminalId) {
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548 if (TerminalId < 10) {
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549 ac[1] = '0' + TerminalId;
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550 } else if (TerminalId < 16) {
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551 ac[1] = 'A' + (TerminalId - 0x0A);
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553 return; // RTT only supports up to 16 virtual terminals.
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555 _ActiveTerminal = TerminalId;
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556 SEGGER_RTT_Write(0, ac, 2);
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559 /*********************************************************************
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561 * SEGGER_RTT_TerminalOut
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563 * Function description
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564 * Writes a string to the given terminal
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565 * without changing the terminal for channel 0.
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568 int SEGGER_RTT_TerminalOut (char TerminalId, const char* s) {
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573 if (TerminalId < 10) {
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574 ac[1] = '0' + TerminalId;
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575 } else if (TerminalId < 16) {
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576 ac[1] = 'A' + (TerminalId - 0x0A);
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578 return -1; // RTT only supports up to 16 virtual terminals.
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580 SEGGER_RTT_Write(0, ac, 2);
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581 r = SEGGER_RTT_WriteString(0, s);
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582 if (TerminalId < 10) {
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583 ac[1] = '0' + _ActiveTerminal;
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584 } else if (TerminalId < 16) {
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585 ac[1] = 'A' + (_ActiveTerminal - 0x0A);
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587 SEGGER_RTT_Write(0, ac, 2);
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591 /*************************** End of file ****************************/
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