Working on a project i want to update the nordic application (firmware) from other MCU, i am having some problem to compute the crc.
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How to we calculate the crc of sample packet : HCI start packet
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Used the function in components/libraries/crc16/crc16.c
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as per the document Bluetooth Core Specification (Volume 4, Part D, Chapter 4) , CRC-CCITT is computed using : Each octet of the Packet Header and Packet Payload is used to com- pute the Data Integrity Check.
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Snippet used to find the crc of start packet for my application
typedef struct { //uint8_t slip_start; uint32_t packet_header; uint32_t dfu_packet_type; uint32_t dfu_udpate_type; uint32_t sizeof_sd; uint32_t sizeof_bl; uint32_t sizeof_app; uint16_t crc_value; //uint8_t slip_end; } __attribute__((__packed__)) dfu_startpacket_t; //dfu_start_packet.slip_start = 0xc0; dfu_start_packet.packet_header = (*(uint32_t *)(&hci_packet_header)); // 0xE0014ED1 dfu_start_packet.dfu_packet_type = 0x03; // DFU start packet dfu_start_packet.dfu_udpate_type = 0x04; // application image dfu_start_packet.sizeof_sd = 0x00; // no SoftDevice image is transferred dfu_start_packet.sizeof_bl = 0x00; // no bootloader image is transferred dfu_start_packet.sizeof_app = 0x5d0c; // size of application //dfu_start_packet.slip_end = 0xc0; } -
To compute the crc below code is used
dfu_start_packet.crc_value = 0x0000; /** crc_value computed : 0xCA0E , once expected as reported in example :0xFCC6 memcpy(temp_buffer, &dfu_start_packet, sizeof(dfu_start_packet)); crc_value = crc16_compute(temp_buffer,sizeof(temp_buffer),0); **/ crc_value = crc16_compute((uint8_t*)(&dfu_start_packet),sizeof(dfu_start_packet),0); -
May i know what i am doing wrong here.
