Handle 0x02/0xF4 group reading response

Author: mnaberez

kwp1281_tool/firmware/kwp1281.c

@@ -484,6 +484,24 @@ kwp_result_t kwp_read_group(uint8_t group)
     uint8_t block_title = kwp_rx_buf[2];
     if (block_title == KWP_ACK) { return KWP_SUCCESS; }
 
+    // some modules like 043906022E don't return the group reading in
+    // an 0xE7 block.  when such modules receive a 0x29 group reading
+    // request, they first send a 0x02 block with header data that
+    // describes the data that will follow.  each successive 0x29
+    // group reading is then answered with an 0xF4 data block.
+    if (block_title == KWP_R_GROUP_READ_HEADER) {
+        result = kwp_send_group_reading_block(group);
+        if (result != KWP_SUCCESS) { return result; }
+
+        result = kwp_receive_block();
+        if (result != KWP_SUCCESS) { return result; }
+
+        block_title = kwp_rx_buf[2];
+        if (block_title != KWP_R_GROUP_READ_DATA) { return KWP_UNEXPECTED; }
+    }
+
+    if (block_title == KWP_R_GROUP_READ_DATA) { return KWP_SUCCESS; }
+
     /*
      * Handle 0xE7 measurements or string response
      */

kwp1281_tool/firmware/kwp1281.h

@@ -95,6 +95,7 @@ uint8_t kwp_component_2[16];    // "        0001"
 //                                                                          Premium 4   5
 #define KWP_READ_IDENT          0x00  /* Read Identification                        X   X       */
 #define KWP_READ_RAM            0x01  /* Read RAM                                   X   X       */
+#define KWP_R_GROUP_READ_HEADER 0x02  /* Response to Group Reading: Header                      */
 #define KWP_READ_ROM_EEPROM     0x03  /* Read ROM or EEPROM                         *1  *1      */
 #define KWP_OUTPUT_TESTS        0x04  /* Actuator/Output Tests                      X   X       */
 #define KWP_CLEAR_FAULTS        0x05  /* Clear Faults                               X   X       */
@@ -115,6 +116,7 @@ uint8_t kwp_component_2[16];    // "        0001"
 #define KWP_SECURITY_ACCESS     0xD7  /* Security Access Request                    *3  *3      */
 #define KWP_R_GROUP_READING     0xE7  /* Response to Group Reading                  X   X       */
 #define KWP_SAFE_CODE           0xF0  /* Request or Response to R/W SAFE Code       X           */
+#define KWP_R_GROUP_READ_DATA   0xF4  /* Response to Group Reading: Data                        */
 #define KWP_R_OUTPUT_TEST       0xF5  /* Response to Actuator/Output Tests          X   X       */
 #define KWP_R_ASCII_DATA        0xF6  /* Response with ASCII Data/ID code           X   X       */
 #define KWP_R_WRITE_EEPROM      0xF9  /* Response to Write EEPROM                       X       */