Lantronix PNT Series PNT-SG3FS GNSS Module Software User Guide - Page 25

2. Firmware Version The Host has to specify the chunk size, the firmware size, and the firmware CRC in the related fields. The chunk size can be selected setting the chunk_size field in the struct ImageOptions; chunk size selection isdescribed in Table 2: Table 2. Chunk_size Bit Field Description Chunk-size bit field [7:4] [3:0] Description Reserved must be zero Set the chunk size value:0: 16 Kbytes; 1: 1 Kbytes; 2: 2 Kbytes; 3: 3 Kbytes; 4: 4 Kbytes; 5: 5 Kbytes; 6: 6 Kbytes; 7: 7 Kbytes; 8: 8 Kbytes; 9: 9 Kbytes; 0: 10 Kbytes; 11: 11 Kbytes; 12: 12 Kbytes; 13: 13 Kbytes; 14: 14 Kbytes; 15: 15 Kbytes; While sending the firmware, data host has to split the binary image in a N chunks with the selected chunk-size (inthe ImageOptions structure); the last chunk size must be equal to the remaining bytes number. Each data chunk will be acknowledged with "ACK" response from the PNT-SG3FS. When all the chunks are sent, the PNT-SG3FS performs a CRC error check on the image data received by the Host;if the check is passed an "ACK" response is sent back to the Host and the new downloaded firmware is validated.Otherwise if the check failed a "NAK" response is sent. In both cases the PNT-SG3FS device resets itself. The firmware upgrade procedure is shown in Figure 2. PNT-SG3FS GNSS Module Software User Guide 25