AP_RangeFinder: Update serial driver for JRE (AP_Math/crc.cpp and crc…

….h are restored before modification)
jfbblue0922 · Jul 26, 2023 · 81c761d · 81c761d
1 parent 9eced89
commit 81c761d
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Showing 3 changed files with 24 additions and 50 deletions.
diff --git a/libraries/AP_Math/crc.cpp b/libraries/AP_Math/crc.cpp
@@ -374,53 +374,6 @@ uint16_t crc16_ccitt(const uint8_t *buf, uint32_t len, uint16_t crc)
     return crc;
 }
 
-/* right shift table */
-static const uint16_t crc16tab_r[256] = {
-  0x0000, 0x1189, 0x2312, 0x329B, 0x4624, 0x57AD, 0x6536, 0x74BF,
-  0x8C48, 0x9DC1, 0xAF5A, 0xBED3, 0xCA6C, 0xDBE5, 0xE97E, 0xF8F7,
-  0x1081, 0x0108, 0x3393, 0x221A, 0x56A5, 0x472C, 0x75B7, 0x643E,
-  0x9CC9, 0x8D40, 0xBFDB, 0xAE52, 0xDAED, 0xCB64, 0xF9FF, 0xE876,
-  0x2102, 0x308B, 0x0210, 0x1399, 0x6726, 0x76AF, 0x4434, 0x55BD,
-  0xAD4A, 0xBCC3, 0x8E58, 0x9FD1, 0xEB6E, 0xFAE7, 0xC87C, 0xD9F5,
-  0x3183, 0x200A, 0x1291, 0x0318, 0x77A7, 0x662E, 0x54B5, 0x453C,
-  0xBDCB, 0xAC42, 0x9ED9, 0x8F50, 0xFBEF, 0xEA66, 0xD8FD, 0xC974,
-  0x4204, 0x538D, 0x6116, 0x709F, 0x0420, 0x15A9, 0x2732, 0x36BB,
-  0xCE4C, 0xDFC5, 0xED5E, 0xFCD7, 0x8868, 0x99E1, 0xAB7A, 0xBAF3,
-  0x5285, 0x430C, 0x7197, 0x601E, 0x14A1, 0x0528, 0x37B3, 0x263A,
-  0xDECD, 0xCF44, 0xFDDF, 0xEC56, 0x98E9, 0x8960, 0xBBFB, 0xAA72,
-  0x6306, 0x728F, 0x4014, 0x519D, 0x2522, 0x34AB, 0x0630, 0x17B9,
-  0xEF4E, 0xFEC7, 0xCC5C, 0xDDD5, 0xA96A, 0xB8E3, 0x8A78, 0x9BF1,
-  0x7387, 0x620E, 0x5095, 0x411C, 0x35A3, 0x242A, 0x16B1, 0x0738,
-  0xFFCF, 0xEE46, 0xDCDD, 0xCD54, 0xB9EB, 0xA862, 0x9AF9, 0x8B70,
-  0x8408, 0x9581, 0xA71A, 0xB693, 0xC22C, 0xD3A5, 0xE13E, 0xF0B7,
-  0x0840, 0x19C9, 0x2B52, 0x3ADB, 0x4E64, 0x5FED, 0x6D76, 0x7CFF,
-  0x9489, 0x8500, 0xB79B, 0xA612, 0xD2AD, 0xC324, 0xF1BF, 0xE036,
-  0x18C1, 0x0948, 0x3BD3, 0x2A5A, 0x5EE5, 0x4F6C, 0x7DF7, 0x6C7E,
-  0xA50A, 0xB483, 0x8618, 0x9791, 0xE32E, 0xF2A7, 0xC03C, 0xD1B5,
-  0x2942, 0x38CB, 0x0A50, 0x1BD9, 0x6F66, 0x7EEF, 0x4C74, 0x5DFD,
-  0xB58B, 0xA402, 0x9699, 0x8710, 0xF3AF, 0xE226, 0xD0BD, 0xC134,
-  0x39C3, 0x284A, 0x1AD1, 0x0B58, 0x7FE7, 0x6E6E, 0x5CF5, 0x4D7C,
-  0xC60C, 0xD785, 0xE51E, 0xF497, 0x8028, 0x91A1, 0xA33A, 0xB2B3,
-  0x4A44, 0x5BCD, 0x6956, 0x78DF, 0x0C60, 0x1DE9, 0x2F72, 0x3EFB,
-  0xD68D, 0xC704, 0xF59F, 0xE416, 0x90A9, 0x8120, 0xB3BB, 0xA232,
-  0x5AC5, 0x4B4C, 0x79D7, 0x685E, 0x1CE1, 0x0D68, 0x3FF3, 0x2E7A,
-  0xE70E, 0xF687, 0xC41C, 0xD595, 0xA12A, 0xB0A3, 0x8238, 0x93B1,
-  0x6B46, 0x7ACF, 0x4854, 0x59DD, 0x2D62, 0x3CEB, 0x0E70, 0x1FF9,
-  0xF78F, 0xE606, 0xD49D, 0xC514, 0xB1AB, 0xA022, 0x92B9, 0x8330,
-  0x7BC7, 0x6A4E, 0x58D5, 0x495C, 0x3DE3, 0x2C6A, 0x1EF1, 0x0F78,
-};
-
-// right shift
-uint16_t crc16_ccitt_r(const uint8_t *buf, uint32_t len, uint16_t crc, uint16_t out)
-{
-    for (uint32_t i = 0; i < len; i++) {
-        crc = (crc >> 8) ^ crc16tab_r[(crc ^ *buf++) & 0x00FF];
-    }
-    crc = crc ^ out;  // output xor
-
-    return crc;
-}
-
 uint16_t crc16_ccitt_GDL90(const uint8_t *buf, uint32_t len, uint16_t crc)
 {
     for (uint32_t i = 0; i < len; i++) {

diff --git a/libraries/AP_Math/crc.h b/libraries/AP_Math/crc.h
@@ -40,7 +40,6 @@ uint8_t crc_sum8(const uint8_t *p, uint8_t len);
 // Copyright (C) 2010 Swift Navigation Inc.
 // Contact: Fergus Noble <[email protected]>
 uint16_t crc16_ccitt(const uint8_t *buf, uint32_t len, uint16_t crc);
-uint16_t crc16_ccitt_r(const uint8_t *buf, uint32_t len, uint16_t crc, uint16_t out);
 
 // CRC16_CCITT algorithm using the GDL90 parser method which is non-standard
 // https://www.faa.gov/nextgen/programs/adsb/archival/media/gdl90_public_icd_reva.pdf

diff --git a/libraries/AP_RangeFinder/AP_RangeFinder_JRE_Serial.cpp b/libraries/AP_RangeFinder/AP_RangeFinder_JRE_Serial.cpp
@@ -14,7 +14,6 @@
  */
 
 #include "AP_RangeFinder_JRE_Serial.h"
-#include <AP_Math/AP_Math.h>
 
 #if AP_RANGEFINDER_JRE_SERIAL_ENABLED
 
@@ -23,6 +22,29 @@
 
 #define DIST_MAX_CM 50000
 
+#define CCITT_INITPARA   0xffff	
+#define CCITT_POLYNOMIAL 0x8408	
+#define CCITT_OUTPARA    0xffff	
+
+/* CRC16CCITT */	
+static uint16_t CalcCRC16CCITT(uint8_t *cbuffer, uint16_t csize)	
+{	
+    uint16_t crc = CCITT_INITPARA;	
+    for (int i = 0; i < csize; i++) {	
+        crc ^= *cbuffer++;	
+        for (int j = 0; j < 8; j++) {	
+            if ((crc & 0x0001) != 0) {	
+                crc >>= 1;	
+                crc ^= CCITT_POLYNOMIAL;	
+            } else {	
+                crc >>= 1;	
+            }	
+        }	
+    }	
+    crc = crc ^ CCITT_OUTPARA;	
+    return crc;	
+}	
+
 bool AP_RangeFinder_JRE_Serial::get_reading(float &reading_m)
 {
     // uart instance check
@@ -80,7 +102,7 @@ bool AP_RangeFinder_JRE_Serial::get_reading(float &reading_m)
         } else { // data set
             if (data_buff_idx >= ARRAY_SIZE(data_buff)) {  // 1 data set complete
                 // crc check
-                uint16_t crc = crc16_ccitt_r(data_buff, ARRAY_SIZE(data_buff) - 2, 0xffff, 0xffff);
+                uint16_t crc = CalcCRC16CCITT(data_buff, ARRAY_SIZE(data_buff) - 2);
                 if ((((crc>>8) & 0xff) == data_buff[15]) && ((crc & 0xff) == data_buff[14])) {
                     // status check
                     if (data_buff[13] & 0x02) { // NTRK